TY 2024 Form 990

- TIN:

Form990

Department of the TreasuryInternal Revenue Service

Return of Organization Exempt From Income Tax

Under section 501(c), 527, or 4947(a)(1) of the Internal Revenue Code (except private foundations)

Do not enter social security numbers on this form as it may be made public.

Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

2024

Open to Public Inspection

A For the 2024 calendar year, or tax year beginning 01-01-2024 , and ending 12-31-2024

BCheck if applicable: Address change Name change Initial return Final return/terminated Amended return Application pending

CName of organization
AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Doing business as

Number and street (or P.O. box if mail is not delivered to street address)
251 18TH ST SOUTH 8TH FLOOR

Room/suite

City or town, state or province, country, and ZIP or foreign postal code
ARLINGTON, VA22202

D Employer identification number

42-0943164

E Telephone number

G Gross receipts $ 28,335,920

F Name and address of principal officer:
VIVEK S KAVADI
251 18TH ST SOUTH 8TH FLOOR
ARLINGTON,VA22202

Tax-exempt status: 501(c)(3) 501(c) ( 6 ) (insert no.) 4947(a)(1) or 527

Website:

WWW.ASTRO.ORG

H(a)

Is this a group return for
subordinates? Yes No

H(b)

Are all subordinates
included?

Yes No

If "No," attach a list. See instructions.

H(c)

Group exemption number

K Form of organization: Corporation Trust Association Other

L Year of formation: 1958

M State of legal domicile: IL

Part I

Summary

1	Briefly describe the organization’s mission or most significant activities: ASTRO IS DEDICATED TO IMPROVING PATIENT CARE THROUGH EDUCATION, CLINICAL PRACTICE, ADVANCEMENTS OF SCIENCE, AND ADVOCACY.
2	Check this box
3	Number of voting members of the governing body (Part VI, line 1a) ........	3	17
4	Number of independent voting members of the governing body (Part VI, line 1b) .....	4	14
5	Total number of individuals employed in calendar year 2024 (Part V, line 2a) ......	5	103
6	Total number of volunteers (estimate if necessary) .............	6	1,850
7a	Total unrelated business revenue from Part VIII, column (C), line 12 ........	7a	1,092,549
b	Net unrelated business taxable income from Form 990-T, Part I, line 11 .........	7b	494,061

		Prior Year	Current Year
8	Contributions and grants (Part VIII, line 1h) .........	697,789	474,206
9	Program service revenue (Part VIII, line 2g) .........	18,414,943	20,729,204
10	Investment income (Part VIII, column (A), lines 3, 4, and 7d ) ....	920,446	1,567,035
11	Other revenue (Part VIII, column (A), lines 5, 6d, 8c, 9c, 10c, and 11e)	2,646,465	2,514,333
12	Total revenue—add lines 8 through 11 (must equal Part VIII, column (A), line 12)	22,679,643	25,284,778
13	Grants and similar amounts paid (Part IX, column (A), lines 1–3 )...	834,120	844,632
14	Benefits paid to or for members (Part IX, column (A), line 4).....	0	0
15	Salaries, other compensation, employee benefits (Part IX, column (A), lines 5–10)	12,444,949	13,057,542
16a	Professional fundraising fees (Part IX, column (A), line 11e) .....	0	0
b	Total fundraising expenses (Part IX, column (D), line 25) 0
17	Other expenses (Part IX, column (A), lines 11a–11d, 11f–24e)....	11,350,477	11,542,711
18	Total expenses. Add lines 13–17 (must equal Part IX, column (A), line 25)	24,629,546	25,444,885
19	Revenue less expenses. Subtract line 18 from line 12.......	-1,949,903	-160,107
		Beginning of Current Year	End of Year
20	Total assets (Part X, line 16).............	52,537,133	52,487,345
21	Total liabilities (Part X, line 26).............	11,805,749	8,505,501
22	Net assets or fund balances. Subtract line 21 from line 20.....	40,731,384	43,981,844

Part II

Signature Block

Under penalties of perjury, I declare that I have examined this return, including accompanying schedules and statements, and to the best of my knowledge and belief, it is true, correct, and complete. Declaration of preparer (other than officer) is based on all information of which preparer has any knowledge.

Sign Here

	Signature of officer	Date

	Type or print name and title

Paid Preparer Use Only

Print/Type preparer's name

Preparer's signature

Date

Check if
self-employed

PTIN

Firm's name

Firm's EIN

Firm's address

Phone no.

May the IRS discuss this return with the preparer shown above? See Instructions. ..........YesNo

For Paperwork Reduction Act Notice, see the separate instructions.

Cat. No. 11282Y Form 990 (2024)

Form 990 (2024)

Page 2

Part III

Statement of Program Service Accomplishments

Check if Schedule O contains a response or note to any line in this Part III..............

Briefly describe the organization’s mission: TO ADVANCE THE PRACTICE OF RADIATION ONCOLOGY BY PROMOTING EXCELLENCE IN PATIENT CARE, PROVIDING OPPORTUNITIES FOR EDUCATIONAL AND PROFESSIONAL DEVELPOMENT, PROMOTING RESEARCH AND DISSEMINATING RESEARCH RESULTS AND REPRESENTING RADIATION ONCOLOGY IN A RAPIDLY EVOLVING HEALTHCARE ENVIRONMENT.

Did the organization undertake any significant program services during the year which were not listed on
the prior Form 990 or 990-EZ? ..................... Yes No

If "Yes," describe these new services on Schedule O.

Did the organization cease conducting, or make significant changes in how it conducts, any program
services? ........................... Yes No

If "Yes," describe these changes on Schedule O.

Describe the organization’s program service accomplishments for each of its three largest program services, as measured by expenses. Section 501(c)(3) and 501(c)(4) organizations are required to report the amount of grants and allocations to others, the total expenses, and revenue, if any, for each program service reported.


4a	(Code: ) (Expenses $ including grants of $ ) (Revenue $ )
	ASTRO ANNUAL MEETING: THE ASTRO ANNUAL MEETING IS THE PREMIER SCIENTIFIC EVENT IN THE FIELD OF RADIATION ONCOLOGY, ATTRACTING OVER 10,000 PROFESSIONALS EACH YEAR, INCLUDING PHYSICIANS, RESEARCHERS, AND HEALTHCARE PRACTITIONERS. THE MEETING FEATURES CUTTING-EDGE SCIENTIFIC PRESENTATIONS, EDUCATIONAL SESSIONS, AND CLINICAL UPDATES DESIGNED TO ADVANCE KNOWLEDGE, PROMOTE BEST PRACTICES, AND IMPROVE PATIENT OUTCOMES IN CANCER CARE. BY FOSTERING COLLABORATION AND PROFESSIONAL DEVELOPMENT, THE ANNUAL MEETING DIRECTLY SUPPORTS ASTRO'S MISSION TO ADVANCE THE PRACTICE OF RADIATION ONCOLOGY THROUGH EDUCATION, RESEARCH, AND QUALITY PATIENT CARE.

4b	(Code: ) (Expenses $ including grants of $ ) (Revenue $ )
	JOURNALS: ASTRO PUBLISHES THREE TOP-NOTCH JOURNALS THAT DISSEMINATE CRITICAL RESEARCH AND CLINICAL GUIDANCE IN THE FIELD OF RADIATION ONCOLOGY. THESE PUBLICATIONS SERVE AS ESSENTIAL RESOURCES FOR CLINICIANS, RESEARCHERS, AND HEALTHCARE PROFESSIONALS, SUPPORTING ASTRO'S MISSION TO ADVANCE THE PRACTICE OF RADIATION ONCOLOGY THROUGH EDUCATION AND SCIENCE.

4c	(Code: ) (Expenses $ including grants of $ ) (Revenue $ )
	MULTIDISCIPLINARY HEAD AND NECK CANCERS SYMPOSIUM: THE MEETING BRINGS TOGETHER PHYSICIANS, RESEARCHERS AND OTHER HEALTHCARE PROFESSIONALS TO SHARE THE LATEST EVIDENCE BASED PRACTICES IN THE DIAGNOSIS AND TREATMENT OF HEAD AND NECK CANCERS THROUGH INTERACTIVE CASE DISCUSSIONS, EDUCATIONAL SESSIONS AND ORAL ABSTRACT PRESENTATIONS. THIS MEETING AIMS TO ENHANCE PROFESSIONAL COLLABORATION AND IMPROVE PATIENT OUTCOMES BY DISSIMINATING CURRENT RESEARCH AND CLINICAL BEST PRACTICES IN THE FIELD.

4d	Other program services (Describe in Schedule O.)
	(Expenses $ including grants of $ ) (Revenue $ )
4e	Total program service expenses

Form 990 (2024)

Page 3

Part IV

Checklist of Required Schedules

Yes

Is the organization described in section 501(c)(3) or 4947(a)(1) (other than a private foundation)? If "Yes," complete Schedule A.....................

Is the organization required to complete Schedule B, Schedule of Contributors? See instructions. Click to see attachment

List of Attached Documents:

// Content

...

Yes

Did the organization engage in direct or indirect political campaign activities on behalf of or in opposition to candidates for public office? If "Yes," complete Schedule C, Part I Click to see attachment

List of Attached Documents:

// Content

.............

Section 501(c)(3) organizations. Did the organization engage in lobbying activities, or have a section 501(h) election in effect during the tax year? If "Yes," complete Schedule C, Part II.........

Is the organization a section 501(c)(4), 501(c)(5), or 501(c)(6) organization that receives membership dues, assessments, or similar amounts as defined in Rev. Proc. 98-19? If "Yes," complete Schedule C, Part III Click to see attachment

List of Attached Documents:

// Content

Yes

Did the organization maintain any donor advised funds or any similar funds or accounts for which donors have the right to provide advice on the distribution or investment of amounts in such funds or accounts? If "Yes," complete Schedule D, Part I Click to see attachment

List of Attached Documents:

// Content

.........................

Did the organization receive or hold a conservation easement, including easements to preserve open space,
the environment, historic land areas, or historic structures? If "Yes," complete Schedule D, Part II Click to see attachment

List of Attached Documents:

// Content

....

Did the organization maintain collections of works of art, historical treasures, or other similar assets? If "Yes,"
complete Schedule D, Part III Click to see attachment

List of Attached Documents:

// Content

..............

Did the organization report an amount in Part X, line 21 for escrow or custodial account liability; serve as a custodian for amounts not listed in Part X; or provide credit counseling, debt management, credit repair, or debt negotiation services? If "Yes," complete Schedule D, Part IV Click to see attachment

List of Attached Documents:

// Content

..............

Did the organization, directly or through a related organization, hold assets in temporarily restricted endowments, permanent endowments, or quasi endowments? If "Yes," complete Schedule D, Part V......

Yes

If the organization’s answer to any of the following questions is "Yes," then complete Schedule D, Parts VI, VII, VIII, IX, or X, as applicable.

Did the organization report an amount for land, buildings, and equipment in Part X, line 10? If "Yes," complete
Schedule D, Part VI. Click to see attachment

List of Attached Documents:

// Content

...................

11a

Yes

Did the organization report an amount for investments—other securities in Part X, line 12 that is 5% or more of its total assets reported in Part X, line 16? If "Yes," complete Schedule D, Part VII Click to see attachment

List of Attached Documents:

// Content

.......

11b

Yes

Did the organization report an amount for investments—program related in Part X, line 13 that is 5% or more of its total assets reported in Part X, line 16? If "Yes," complete Schedule D, Part VIII Click to see attachment

List of Attached Documents:

// Content

.......

11c

Did the organization report an amount for other assets in Part X, line 15 that is 5% or more of its total assets reported in Part X, line 16? If "Yes," complete Schedule D, Part IX Click to see attachment

List of Attached Documents:

// Content

............

11d

Yes

Did the organization report an amount for other liabilities in Part X, line 25? If "Yes," complete Schedule D, Part X Click to see attachment

List of Attached Documents:

// Content

11e

Yes

Did the organization’s separate or consolidated financial statements for the tax year include a footnote that addresses the organization’s liability for uncertain tax positions under FIN 48 (ASC 740)? If "Yes," complete Schedule D, Part X Click to see attachment

List of Attached Documents:

// Content

11f

Yes

12a

Did the organization obtain separate, independent audited financial statements for the tax year? If "Yes," complete
Schedule D, Parts XI and XII Click to see attachment

List of Attached Documents:

// Content

......................

12a

Was the organization included in consolidated, independent audited financial statements for the tax year? If "Yes," and if the organization answered "No" to line 12a, then completing Schedule D, Parts XI and XII is optional Click to see attachment

List of Attached Documents:

// Content

12b

Yes

Is the organization a school described in section 170(b)(1)(A)(ii)? If "Yes," complete Schedule E

14a

Did the organization maintain an office, employees, or agents outside of the United States? .....

14a

Did the organization have aggregate revenues or expenses of more than $10,000 from grantmaking, fundraising, business, investment, and program service activities outside the United States, or aggregate foreign investments valued at $100,000 or more? If "Yes," complete Schedule F, Parts I and IV.........

14b

Did the organization report on Part IX, column (A), line 3, more than $5,000 of grants or other assistance to or for any foreign organization? If “Yes,” complete Schedule F, Parts II and IV.....

Did the organization report on Part IX, column (A), line 3, more than $5,000 of aggregate grants or other assistance to or for foreign individuals? If “Yes,” complete Schedule F, Parts III and IV...

Did the organization report a total of more than $15,000 of expenses for professional fundraising services on Part IX, column (A), lines 6 and 11e? If "Yes," complete Schedule G, Part I. See instructions. ....

Did the organization report more than $15,000 total of fundraising event gross income and contributions on Part VIII, lines 1c and 8a? If "Yes," complete Schedule G, Part II............

Did the organization report more than $15,000 of gross income from gaming activities on Part VIII, line 9a? If "Yes," complete Schedule G, Part III...................

20a

Did the organization operate one or more hospital facilities? If "Yes," complete Schedule H....

20a

If "Yes" to line 20a, did the organization attach a copy of its audited financial statements to this return?

20b

Did the organization report more than $5,000 of grants or other assistance to any domestic organization or domestic government on Part IX, column (A), line 1? If “Yes,” complete Schedule I, Parts I and II..... Click to see attachment

List of Attached Documents:

// Content

Yes

Form 990 (2024)

Page 4

Part IV

Checklist of Required Schedules (continued)

Yes

Did the organization report more than $5,000 of grants or other assistance to or for domestic individuals on Part IX, column (A), line 2? If “Yes,” complete Schedule I, Parts I and III........ Click to see attachment

List of Attached Documents:

// Content

Did the organization answer "Yes" to Part VII, Section A, line 3, 4, or 5, about compensation of the organization’s current and former officers, directors, trustees, key employees, and highest compensated employees? If "Yes," complete Schedule J....................... Click to see attachment

List of Attached Documents:

// Content

Yes

24a

Did the organization have a tax-exempt bond issue with an outstanding principal amount of more than $100,000 as of the last day of the year, that was issued after December 31, 2002? If “Yes,” answer lines 24b through 24d and complete Schedule K. If “No,” go to line 25a...............

24a

Did the organization invest any proceeds of tax-exempt bonds beyond a temporary period exception?...

24b

Did the organization maintain an escrow account other than a refunding escrow at any time during the year
to defease any tax-exempt bonds? ...............

24c

Did the organization act as an "on behalf of" issuer for bonds outstanding at any time during the year?...

24d

25a

Section 501(c)(3), 501(c)(4), and 501(c)(29) organizations. Did the organization engage in an excess benefit transaction with a disqualified person during the year? If "Yes," complete Schedule L, Part I ....

25a

Is the organization aware that it engaged in an excess benefit transaction with a disqualified person in a prior year, and that the transaction has not been reported on any of the organization’s prior Forms 990 or 990-EZ? If "Yes," complete Schedule L, Part I.......................

25b

Did the organization report any amount on Part X, line 5 or 22 for receivables from or payables to any current or former officer, director, trustee, key employee, creator or founder, substantial contributor, or 35% controlled entity or family member of any of these persons? If "Yes," complete Schedule L, Part II...........

Did the organization provide a grant or other assistance to any current or former officer, director, trustee, key employee, creator or founder, substantial contributor, or employee thereof, a grant selection committee member, or to a 35% controlled entity (including an employee thereof) or family member of any of these persons?

If "Yes," complete

Schedule L, Part III.........................

Was the organization a party to a business transaction with one of the following parties (see the Schedule L, Part IV instructions for applicable filing thresholds, conditions, and exceptions):

A current or former officer, director, trustee, key employee, creator or founder, or substantial contributor? If "Yes," complete Schedule L, Part IV......................

28a

A family member of any individual described in line 28a? If "Yes," complete Schedule L, Part IV.....

28b

A 35% controlled entity of one or more individuals and/or organizations described in line 28a or 28b? If "Yes," complete Schedule L, Part IV.....................

28c

Did the organization receive more than $25,000 in non-cash contributions? If "Yes," complete Schedule M..

Did the organization receive contributions of art, historical treasures, or other similar assets, or qualified conservation contributions? If "Yes," complete Schedule M .................

Did the organization liquidate, terminate, or dissolve and cease operations? If "Yes," complete Schedule N, Part I

Did the organization sell, exchange, dispose of, or transfer more than 25% of its net assets? If "Yes," complete Schedule N, Part II........................

Did the organization own 100% of an entity disregarded as separate from the organization under Regulations sections 301.7701-2 and 301.7701-3? If "Yes," complete Schedule R, Part I............ Click to see attachment

List of Attached Documents:

// Content

Was the organization related to any tax-exempt or taxable entity? If "Yes," complete Schedule R, Part II, III, or IV, and Part V, line 1......................... Click to see attachment

List of Attached Documents:

// Content

Yes

35a

Did the organization have a controlled entity within the meaning of section 512(b)(13)?

35a

Yes

If ‘Yes’ to line 35a, did the organization receive any payment from or engage in any transaction with a controlled entity within the meaning of section 512(b)(13)? If "Yes," complete Schedule R, Part V, line 2 ... Click to see attachment

List of Attached Documents:

// Content

35b

Yes

Section 501(c)(3) organizations. Did the organization make any transfers to an exempt non-charitable related organization? If "Yes," complete Schedule R, Part V, line 2.............

Did the organization conduct more than 5% of its activities through an entity that is not a related organization and that is treated as a partnership for federal income tax purposes? If "Yes," complete Schedule R, Part VI Click to see attachment

List of Attached Documents:

// Content

Did the organization complete Schedule O and provide explanations on Schedule O for Part VI, lines 11b and 19? Note. All Form 990 filers are required to complete Schedule O. ............

Yes

Part V

Statements Regarding Other IRS Filings and Tax Compliance
Check if Schedule O contains a response or note to any line in this Part V...........

Yes

Enter the number reported in box 3 of Form 1096. Enter -0- if not applicable ..

253

Enter the number of Forms W-2G included on line 1a. Enter -0- if not applicable .

Did the organization comply with backup withholding rules for reportable payments to vendors and reportable gaming (gambling) winnings to prize winners? ..................

Yes

Form 990 (2024)

Page 5

Part V

Statements Regarding Other IRS Filings and Tax Compliance (continued)

Enter the number of employees reported on Form W-3, Transmittal of Wage and
Tax Statements, filed for the calendar year ending with or within the year covered by this return ..................

103

If at least one is reported on line 2a, did the organization file all required federal employment tax returns?

Yes

Did the organization have unrelated business gross income of $1,000 or more during the year?...

Yes

If “Yes,” has it filed a Form 990-T for this year? If “No” to line 3b, provide an explanation in Schedule O...

Yes

At any time during the calendar year, did the organization have an interest in, or a signature or other authority over, a financial account in a foreign country (such as a bank account, securities account, or other financial account)? ..

If "Yes," enter the name of the foreign country:
See instructions for filing requirements for FinCEN Form 114, Report of Foreign Bank and Financial Accounts (FBAR).

Was the organization a party to a prohibited tax shelter transaction at any time during the tax year? ..

Did any taxable party notify the organization that it was or is a party to a prohibited tax shelter transaction?

If "Yes," to line 5a or 5b, did the organization file Form 8886-T? ............

Does the organization have annual gross receipts that are normally greater than $100,000, and did the organization solicit any contributions that were not tax deductible as charitable contributions? ...

Yes

If "Yes," did the organization include with every solicitation an express statement that such contributions or gifts were not tax deductible? ......................

Yes

Organizations that may receive deductible contributions under section 170(c).

Did the organization receive a payment in excess of $75 made partly as a contribution and partly for goods and services provided to the payor? ....................

If "Yes," did the organization notify the donor of the value of the goods or services provided? .....

Did the organization sell, exchange, or otherwise dispose of tangible personal property for which it was required to file Form 8282? .........................

If "Yes," indicate the number of Forms 8282 filed during the year ....

Did the organization receive any funds, directly or indirectly, to pay premiums on a personal benefit contract?

Did the organization, during the year, pay premiums, directly or indirectly, on a personal benefit contract? ..

If the organization received a contribution of qualified intellectual property, did the organization file Form 8899 as required? ......................

If the organization received a contribution of cars, boats, airplanes, or other vehicles, did the organization file a Form 1098-C? ..........................

Sponsoring organizations maintaining donor advised funds. Did a donor advised fund maintained by the sponsoring organization have excess business holdings at any time during the year? ........

Sponsoring organizations maintaining donor advised funds.

Did the sponsoring organization make any taxable distributions under section 4966?........

Did the sponsoring organization make a distribution to a donor, donor advisor, or related person?...

Section 501(c)(7) organizations. Enter:

Initiation fees and capital contributions included on Part VIII, line 12 ...

10a

Gross receipts, included on Form 990, Part VIII, line 12, for public use of club facilities

10b

Section 501(c)(12) organizations. Enter:

Gross income from members or shareholders .........

11a

Gross income from other sources. (Do not net amounts due or paid to other sources against amounts due or received from them.) ..........

11b

12a

Section 4947(a)(1) non-exempt charitable trusts. Is the organization filing Form 990 in lieu of Form 1041?

12a

If "Yes," enter the amount of tax-exempt interest received or accrued during the year.

12b

Section 501(c)(29) qualified nonprofit health insurance issuers.

Is the organization licensed to issue qualified health plans in more than one state? .........
Note. See the instructions for additional information the organization must report on Schedule O.

13a

Enter the amount of reserves the organization is required to maintain by the states in which the organization is licensed to issue qualified health plans ....

13b

Enter the amount of reserves on hand ............

13c

14a

Did the organization receive any payments for indoor tanning services during the tax year?.....

14a

If "Yes," has it filed a Form 720 to report these payments? If "No," provide an explanation in Schedule O..

14b

Is the organization subject to the section 4960 tax on payment(s) of more than $1,000,000 in remuneration or excess parachute payment(s) during the year? ....................
If "Yes," see the instructions and file Form 4720, Schedule N.

Is the organization an educational institution subject to the section 4968 excise tax on net investment income? ..
If "Yes," complete Form 4720, Schedule O.

Section 501(c)(21) organizations. Did the trust, or any disqualified or other person engage in any activities that would result in the imposition of an excise tax under section 4951, 4952, or 4953? ..
If "Yes," complete Form 6069.

Form 990 (2024)

Page 6

Part VI

Governance, Management, and Disclosure. For each "Yes" response to lines 2 through 7b below, and for a "No" response to lines 8a, 8b, or 10b below, describe the circumstances, processes, or changes in Schedule O. See instructions.

Check if Schedule O contains a response or note to any line in this Part VI..............

Section A. Governing Body and Management

Yes

Enter the number of voting members of the governing body at the end of the tax year

If there are material differences in voting rights among members of the governing body, or if the governing body delegated broad authority to an executive committee or similar committee, explain in Schedule O.

Enter the number of voting members included in line 1a, above, who are independent

Did any officer, director, trustee, or key employee have a family relationship or a business relationship with any other officer, director, trustee, or key employee? .................

Did the organization delegate control over management duties customarily performed by or under the direct supervision of officers, directors or trustees, or key employees to a management company or other person? .

Did the organization make any significant changes to its governing documents since the prior Form 990 was filed? .

Yes

Did the organization become aware during the year of a significant diversion of the organization’s assets? .

Did the organization have members or stockholders? ................

Yes

Did the organization have members, stockholders, or other persons who had the power to elect or appoint one or more members of the governing body? ....................

Yes

Are any governance decisions of the organization reserved to (or subject to approval by) members, stockholders, or persons other than the governing body? ...................

Yes

Did the organization contemporaneously document the meetings held or written actions undertaken during the year by the following:

The governing body? .......................

Yes

Each committee with authority to act on behalf of the governing body? ............

Yes

Is there any officer, director, trustee, or key employee listed in Part VII, Section A, who cannot be reached at the organization’s mailing address? If "Yes," provide the names and addresses in Schedule O.......

Section B. Policies (This Section B requests information about policies not required by the Internal Revenue Code.)

Yes

10a

Did the organization have local chapters, branches, or affiliates? ............

10a

If "Yes," did the organization have written policies and procedures governing the activities of such chapters, affiliates, and branches to ensure their operations are consistent with the organization's exempt purposes?

10b

11a

Has the organization provided a complete copy of this Form 990 to all members of its governing body before filing the form? ............................

11a

Yes

Describe on Schedule O the process, if any, used by the organization to review this Form 990. .....

12a

Did the organization have a written conflict of interest policy? If "No," go to line 13.......

12a

Yes

Were officers, directors, or trustees, and key employees required to disclose annually interests that could give rise to conflicts? ..........................

12b

Yes

Did the organization regularly and consistently monitor and enforce compliance with the policy? If "Yes," describe on Schedule O how this was done...................

12c

Yes

Did the organization have a written whistleblower policy? ...............

Yes

Did the organization have a written document retention and destruction policy? .........

Yes

Did the process for determining compensation of the following persons include a review and approval by independent persons, comparability data, and contemporaneous substantiation of the deliberation and decision?

The organization’s CEO, Executive Director, or top management official ...........

15a

Yes

Other officers or key employees of the organization ................

15b

Yes

If "Yes" to line 15a or 15b, describe the process on Schedule O. See instructions.

16a

Did the organization invest in, contribute assets to, or participate in a joint venture or similar arrangement with a taxable entity during the year? ......................

16a

If "Yes," did the organization follow a written policy or procedure requiring the organization to evaluate its participation in joint venture arrangements under applicable federal tax law, and take steps to safeguard the organization’s exempt status with respect to such arrangements? ............

16b

Section C. Disclosure

List the states with which a copy of this Form 990 is required to be filed

Section 6104 requires an organization to make its Form 1023 (1024 or 1024-A, if applicable), 990, and 990-T (section 501(c)(3)s only) available for public inspection. Indicate how you made these available. Check all that apply.

Own website Another's website Upon request Other (explain in Schedule O)

Describe in Schedule O whether (and if so, how) the organization made its governing documents, conflict of interest policy, and financial statements available to the public during the tax year.

State the name, address, and telephone number of the person who possesses the organization's books and records:
DEMELASH AYALEW251 18TH ST SOUTH 8TH FLOOR ARLINGTON,VA22202 (703) 839-7312

Form 990 (2024)

Page 7

Part VII

Compensation of Officers, Directors,Trustees, Key Employees, Highest Compensated Employees, and Independent Contractors

Check if Schedule O contains a response or note to any line in this Part VII..............

Section A. Officers, Directors, Trustees, Key Employees, and Highest Compensated Employees

1a Complete this table for all persons required to be listed. Report compensation for the calendar year ending with or within the organization’s tax year.
RoundBullet

List all of the organization’s current officers, directors, trustees (whether individuals or organizations), regardless of amount
of compensation. Enter -0- in columns (D), (E), and (F) if no compensation was paid.

List all of the organization’s current key employees, if any. See the instructions for definition of "key employee."

List the organization’s five current highest compensated employees (other than an officer, director, trustee or key employee)
who received reportable compensation (box 5 of Form W-2, box 6 of Form 1099-MISC, and/or box 1 of Form 1099-NEC) of more than $100,000 from the organization and any related organizations.

List all of the organization’s former officers, key employees, or highest compensated employees who received more than $100,000
of reportable compensation from the organization and any related organizations.

List all of the organization’s former directors or trustees that received, in the capacity as a former director or trustee of the
organization, more than $10,000 of reportable compensation from the organization and any related organizations.

See the instructions for the order in which to list the persons above.

Check this box if neither the organization nor any related organization compensated any current officer, director, or trustee.

(A) Name and title	(B) Average hours per week (list any hours for related organizations below dotted line)	(C) Position (do not check more than one box, unless person is both an officer and a director/trustee)		(D) Reportable compensation from the organization (W-2/1099-MISC/1099-NEC)	(E) Reportable compensation from related organizations (W-2/1099-MISC/1099-NEC)	(F) Estimated amount of other compensation from the organization and related organizations
(A) Name and title
(1) CHELSEA PINNIX EDUC COUNCIL...................................................................... VICE CHAIR, THEN CHAIR FROM 10/24	2.00 ................. 0.00	X		0	0	0
(2) CASEY CHOLLET-LIPSCOMB GOV'T...................................................................... REL CNCL VC CHR, CHAIR FROM 10/24	2.00 ................. 0.00	X		0	0	0
(3) JOHN BUATTI SCIENCE COUNCIL...................................................................... VICE CHAIR, THEN CHAIR FROM 10/24	2.00 ................. 1.00	X		0	0	0
(4) IRIS C GIBBS...................................................................... HACE COUNCIL CHAIR UNTIL 9/24	2.00 ................. 0.00	X		0	0	0
(5) ERIC FORD...................................................................... CLIN AFF & QC CHAIR UNTIL 9/24	2.00 ................. 0.00	X		0	0	0
(6) DOUGLAS MARTIN CLIN AFF...................................................................... QC VC CHR, THEN CHAIR FROM 10/24	2.00 ................. 0.00	X		0	0	0
(7) RONALD D ENNIS...................................................................... GOV'T REL CNCL CHAIR UNTIL 9/24	2.00 ................. 0.00	X		0	0	0
(8) SAMEER KEOLE PRESIDENT-ELECT...................................................................... THEN PRESIDENT FROM 10/24	2.00 ................. 0.00	X		0	0	0
(9) VIVEK S KAVADI HEALTH POLICY...................................................................... CNCL VC CHR, THEN CEO FROM 11/24	40.00 ................. 0.00	X	X	135,239	0	8,704
(10) WENDY WOODWARD...................................................................... SCIENCE COUNCIL VICE CHAIR	2.00 ................. 0.00	X		0	0	0
(11) AUSTIN J SIM...................................................................... EARLY CAREER REP EX-OFFICIO	2.00 ................. 0.00	X		0	0	0
(12) BETH ERICKSON...................................................................... EDUC COUNCIL CHAIR UNTIL 9/24	2.00 ................. 0.00	X		0	0	0
(13) CURTILAND DEVILLE HACE CNCL...................................................................... VICE CHAIR, THEN CHAIR FROM 10/24	2.00 ................. 0.00	X		9,500	0	0
(14) CATHERYN YASHAR...................................................................... HEALTH POLICY COUNCIL CHAIR	2.00 ................. 0.00	X		10,500	0	0
(15) GERALDINE JACOBSON...................................................................... IMMEDIATE PAST CHAIR UNTIL 9/24	2.00 ................. 0.00	X	X	0	0	0
(16) MICHAEL KUETTEL...................................................................... SECRETARY/TREASURER	2.00 ................. 0.00	X	X	20,000	0	0
(17) JEFF M MICHALSKI CHAIR...................................................................... THEN IMMED PAST CHAIR FROM 10/24	2.00 ................. 1.00	X	X	0	0	0

Form 990 (2024)

Page 8

Part VII

Section A. Officers, Directors, Trustees, Key Employees, and Highest Compensated Employees (continued)

(A) Name and title	(B) Average hours per week (list any hours for related organizations below dotted line)	(C) Position (do not check more than one box, unless person is both an officer and a director/trustee)				(D) Reportable compensation from the organization (W-2/1099-MISC/1099-NEC)	(E) Reportable compensation from related organizations (W-2/1099-MISC/1099-NEC)	(F) Estimated amount of other compensation from the organization and related organizations
(A) Name and title
(18) HOWARD SANDLER........................................................................ PRESIDENT, THEN CHAIR FROM 10/24	2.00 .......................0.00	X	X			0	0	0
(19) NEHA VAPIWALA........................................................................ PRESIDENT-ELECT FROM 10/24	2.00 .......................0.00	X	X			0	0	0
(20) JEAN WRIGHT CLIN AFFAIRS........................................................................ & QC VICE-CHAIR FROM 10/24	2.00 .......................0.00	X				0	0	0
(21) ANDREA NG EDUCATION........................................................................ COUNCIL VICE CHAIR FROM 10/24	2.00 .......................0.00	X				0	0	0
(22) CHRISTOPHER CORSO GOV'T REL........................................................................ COUNCIL VICE CHAIR FROM 10/24	2.00 .......................0.00	X				0	0	0
(23) MALIKA SIKER........................................................................ HACE CNCL VICE CHAIR FROM 10/24	2.00 .......................0.00	X				0	0	0
(24) AMAR REWARI HEALTH POLICY........................................................................ COUNCIL VICE CHAIR FROM 10/24	2.00 .......................0.00	X				20,500	0	0
(25) MICHAEL LECOMPTE........................................................................ ARRO REP EX-OFFICIO FROM 10/24	2.00 .......................0.00	X				0	0	0
(26) LAURA I THEVENOT........................................................................ CEO UNTIL 11/24	36.00 .......................4.00		X			805,285	0	69,093
(27) TERRY KARRAS........................................................................ CFO	40.00 .......................0.00		X			223,431	0	54,922
(28) EMILY WILSON........................................................................ EXECUTIVE VICE PRESIDENT	40.00 .......................0.00			X		320,548	0	47,521
(29) DAVE ADLER........................................................................ VP, ADVOCACY & CLINICAL AFFAIRS	40.00 .......................0.00			X		249,371	0	58,606
(30) CHRIS NEUMANN........................................................................ VP, EDUCATION	40.00 .......................0.00			X		176,046	0	49,979
(31) ANNA ARNONE........................................................................ VP, MEMBERSHIP & COMMUNICATION	40.00 .......................0.00			X		199,427	0	22,428
(32) ANNE HUBBARD........................................................................ DIRECTOR OF HEALTH POLICY	40.00 .......................0.00				X	227,661	0	55,249
(33) LAURA GOGAL........................................................................ GENERAL COUNSEL	40.00 .......................0.00				X	242,543	0	45,187
(34) SAMANTHA DAWES........................................................................ DIRECTOR OF QUALITY IMPROVEMENT	40.00 .......................0.00				X	192,409	0	21,166
(35) KIRSTA SUGGS........................................................................ DIRECTOR OF HACE	40.00 .......................0.00				X	178,957	0	31,383
(36) JEFF WHITE........................................................................ DIRECTOR OF PUBLIC RELATIONS	40.00 .......................0.00				X	171,364	0	30,435

1b	Sub-Total..............
c	Total from continuation sheets to Part VII, Section A..
d	Total (add lines 1b and 1c).........	3,182,781	0	494,673

Total number of individuals (including but not limited to those listed above) who received more than $100,000 of reportable compensation from the organization 40

Yes

Did the organization list any former officer, director or trustee, key employee, or highest compensated employee on line 1a? If "Yes," complete Schedule J for such individual ..............

For any individual listed on line 1a, is the sum of reportable compensation and other compensation from the organization and related organizations greater than $150,000? If "Yes," complete Schedule J for such
individual...........................

Yes

Did any person listed on line 1a receive or accrue compensation from any unrelated organization or individual for services rendered to the organization? If "Yes," complete Schedule J for such person ........

Section B. Independent Contractors

Complete this table for your five highest compensated independent contractors that received more than $100,000 of compensation from the organization. Report compensation for the calendar year ending with or within the organization’s tax year.

(A) Name and business address	(B) Description of services	(C) Compensation
PROJECTION PRESENTATION TECH 5803 ROLLING RD SPRINGFIELD,VA22152	AUDIOVISUAL SERVICES	1,252,354
ELSEVIER INC 1600 JOHN F KENNEDY BLVD PHILADELPHIA,PA19103	PUBLICATION SERVICES	573,424
JW MARRIOTT PHOENIX DESERT RIDGE RESORT 5350 E MARRIOT DR PHOENIX,AZ85054	CONFERENCE AND ACCOMODATION SERVICES	515,713
J SPARGO & ASSOCIATES INC 11208 WAPLES MILL ROAD FAIRFAX,VA22030	EVENT MANAGEMENT SERVICES	386,842
GLOBAL EXPERIENCE SPECIALISTS INC 7000 LINDELL AVENUE LAS VEGAS,NV89118	EQUIPMENT RENTAL AND MEETING MANAGEMENT	326,736
2 Total number of independent contractors (including but not limited to those listed above) who received more than $100,000 of compensation from the organization 14

Form 990 (2024)

Page 9

Part VIII

Statement of Revenue

Check if Schedule O contains a response or note to any line in this Part VIII.............

(A)
Total revenue

(B)
Related or
exempt
function
revenue

(D)
Revenue
excluded from
tax under sections
512 - 514

1a	Federated campaigns..		1a
b	Membership dues..		1b
c	Fundraising events..		1c
d	Related organizations		1d	10,000
e	Government grants (contributions)		1e	35,298

f	All other contributions, gifts, grants, and similar amounts not included above		1f	428,908

g	Noncash contributions included in lines 1a - 1f:$		1g

h Total. Add lines 1a-1f.......		474,206

		Business Code
2a	MEETINGS AND EDUCATION	900099	12,844,640	12,543,640	301,000
b	MEMBERSHIP DUES	900099	4,524,385	4,524,385
c	PUBLICATIONS	900099	1,684,891	1,104,542	580,349
d	QUALITY IMPROVEMENT	900099	1,293,236	1,293,236
e	OTHER PROGRAM SERVICE	900099	258,079	258,079
f	All other program service revenue.		123,973	123,973
g	Total. Add lines 2a–2f .....		20,729,204

3 Investment income (including dividends, interest, and othersimilar amounts) ......			1,302,859			1,302,859
4 Income from investment of tax-exempt bond proceeds
5 Royalties...........			1,991,780			1,991,780
			(i) Real	(ii) Personal
6a	Gross rents	6a
b	Less: rental expenses	6b
c	Rental income or (loss)	6c
d	Net rental income or (loss).......
			(i) Securities	(ii) Other
7a	Gross amount from sales of assets other than inventory	7a	3,311,046
b	Less: cost or other basis and sales expenses	7b	3,046,870
c	Gain or (loss)	7c	264,176
d	Net gain or (loss).........			264,176			264,176
8a	Gross income from fundraising events (not including $ of contributions reported on line 1c). See Part IV, line 18 ....
			8a
b	Less: direct expenses ...		8b
c	Net income or (loss) from fundraising events..
9a	Gross income from gaming activities. See Part IV, line 19 ...
			9a
b	Less: direct expenses ...		9b
c	Net income or (loss) from gaming activities..
10a	Gross sales of inventory, less returns and allowances ..
			10a	2,859
b	Less: cost of goods sold ..		10b	4,272
c	Net income or (loss) from sales of inventory..			-1,413		-1,413

Business Code
11a	REBATES AND LABELS		900099	311,320	311,320
b	CAREER CENTER		900099	212,613		212,613
c	MISCELLANEOUS		900099	33	33
d	All other revenue ....
e	Total. Add lines 11a–11d ......			523,966
12	Total revenue. See instructions.....			25,284,778	20,159,208	1,092,549	3,558,815

Form 990 (2024)

Page 10

Part IX

Statement of Functional Expenses

Section 501(c)(3) and 501(c)(4) organizations must complete all columns. All other organizations must complete column (A).Check if Schedule O contains a response or note to any line in this Part IX..............

Do not include amounts reported on lines 6b, 7b, 8b, 9b, and 10b of Part VIII.		(A) Total expenses	(B) Program service expenses	(C) Management and general expenses	(D) Fundraising expenses

1	Grants and other assistance to domestic organizations and domestic governments. See Part IV, line 21 ....	844,632
2	Grants and other assistance to domestic individuals. See Part IV, line 22 ...........
3	Grants and other assistance to foreign organizations, foreign governments, and foreign individuals. See Part IV, lines 15 and 16. .............
4	Benefits paid to or for members .......
5	Compensation of current officers, directors, trustees, and key employees ...........	2,429,100
6	Compensation not included above, to disqualified persons (as defined under section 4958(f)(1)) and persons described in section 4958(c)(3)(B) .........
7	Other salaries and wages........	8,075,226
8	Pension plan accruals and contributions (include section 401(k) and 403(b) employer contributions) ....	753,216
9	Other employee benefits .......	1,097,766
10	Payroll taxes ...........	702,234
11	Fees for services (non-employees):
a	Management ......
b	Legal .........	193,473
c	Accounting ...........	50,772
d	Lobbying ...........	268,630
e	Professional fundraising services. See Part IV, line 17
f	Investment management fees ......	94,662
g	Other (If line 11g amount exceeds 10% of line 25, column (A) amount, list line 11g expenses on Schedule O)	2,175,058
12	Advertising and promotion ....
13	Office expenses .......	826,760
14	Information technology ......	1,028,508
15	Royalties ..	11,873
16	Occupancy ...........	778,374
17	Travel ............	1,860,596
18	Payments of travel or entertainment expenses for any federal, state, or local public officials .
19	Conferences, conventions, and meetings ....	2,593,126
20	Interest ...........
21	Payments to affiliates .......
22	Depreciation, depletion, and amortization ..	317,206
23	Insurance ...	166,339
24	Other expenses. Itemize expenses not covered above (List miscellaneous expenses in line 24e. If line 24e amount exceeds 10% of line 25, column (A) amount, list line 24e expenses on Schedule O.)
a	UBI TAXES	181,442
b	DUES AND SUBSCRIPTIONS	739,599
c	HONORARIA	649,914
d	GIFTS AND AWARDS	36,088
e	All other expenses	-429,709
25	Total functional expenses. Add lines 1 through 24e	25,444,885
26	Joint costs. Complete this line only if the organization reported in column (B) joint costs from a combined educational campaign and fundraising solicitation. Check here if following SOP 98-2 (ASC 958-720).

Form 990 (2024)

Page 11

Part X

Balance Sheet

Check if Schedule O contains a response or note to any line in this Part IX..............

				(A) Beginning of year		(B) End of year

1	Cash–non-interest-bearing ........				1
2	Savings and temporary cash investments .........			822,737	2	2,125,287
3	Pledges and grants receivable, net ......				3
4	Accounts receivable, net .............			1,249,843	4	676,814
5	Loans and other receivables from any current or former officer, director, trustee, key employee, creator or founder, substantial contributor, or 35% controlled entity or family member of any of these persons .......
					5
6	Loans and other receivables from other disqualified persons (as defined under section 4958(f)(1)), and persons described in section 4958(c)(3)(B) ...
					6
7	Notes and loans receivable, net ...........				7
8	Inventories for sale or use ............				8
9	Prepaid expenses and deferred charges ......			1,079,893	9	1,031,753
10a	Land, buildings, and equipment: cost or other basis. Complete Part VI of Schedule D	10a	5,665,852
b	Less: accumulated depreciation	10b	4,922,965	1,048,552	10c	742,887
11	Investments—publicly traded securities .			37,652,460	11	38,660,788
12	Investments—other securities. See Part IV, line 11 .....			7,087,308	12	6,332,776
13	Investments—program-related. See Part IV, line 11 ..				13
14	Intangible assets ...............				14
15	Other assets. See Part IV, line 11 ...........			3,596,340	15	2,917,040
16	Total assets. Add lines 1 through 15 (must equal line 33)...			52,537,133	16	52,487,345

17	Accounts payable and accrued expenses .....	1,920,775	17	1,368,471
18	Grants payable ...		18
19	Deferred revenue .........	4,803,354	19	3,096,403
20	Tax-exempt bond liabilities .........		20
21	Escrow or custodial account liability. Complete Part IV of Schedule D		21
22	Loans and other payables to any current or former officer, director, trustee, key employee, creator or founder, substantial contributor, or 35% controlled entity or family member of any of these persons .........
			22
23	Secured mortgages and notes payable to unrelated third parties ..		23
24	Unsecured notes and loans payable to unrelated third parties ..		24
25	Other liabilities (including federal income tax, payables to related third parties, and other liabilities not included on lines 17 - 24). Complete Part X of Schedule D	5,081,620	25	4,040,627
26	Total liabilities. Add lines 17 through 25..	11,805,749	26	8,505,501

	Organizations that follow FASB ASC 958, check here and complete lines 27, 28, 32, and 33.
27	Net assets without donor restrictions ..........	40,731,384	27	43,981,844
28	Net assets with donor restrictions ...........		28
	Organizations that do not follow FASB ASC 958, check here and complete lines 29 through 33.
29	Capital stock or trust principal, or current funds .....		29
30	Paid-in or capital surplus, or land, building or equipment fund ...		30
31	Retained earnings, endowment, accumulated income, or other funds		31
32	Total net assets or fund balances ...........	40,731,384	32	43,981,844
33	Total liabilities and net assets/fund balances ........	52,537,133	33	52,487,345

Form 990 (2024)

Page 12

Part XI

Reconcilliation of Net Assets

Check if Schedule O contains a response or note to any line in this Part XI..............

Total revenue (must equal Part VIII, column (A), line 12) ............

25,284,778

Total expenses (must equal Part IX, column (A), line 25) ............

25,444,885

Revenue less expenses. Subtract line 2 from line 1 ..............

-160,107

Net assets or fund balances at beginning of year (must equal Part X, line 32, column (A)) ..

40,731,384

Net unrealized gains (losses) on investments ...............

3,410,567

Donated services and use of facilities .................

Investment expenses .....................

Prior period adjustments .....................

Other changes in net assets or fund balances (explain in Schedule O) ........

Net assets or fund balances at end of year. Combine lines 3 through 9 (must equal Part X, line 32, column (B))

43,981,844

Part XII

Financial Statements and Reporting

Check if Schedule O contains a response or note to any line in this Part XII.............

Yes

Accounting method used to prepare the Form 990: Cash Accrual Other
If the organization changed its method of accounting from a prior year or checked "Other," explain on
Schedule O.

Were the organization’s financial statements compiled or reviewed by an independent accountant?

If ‘Yes,’ check a box below to indicate whether the financial statements for the year were compiled or reviewed on a separate basis, consolidated basis, or both:

Separate basis Consolidated basis Both consolidated and separate basis

Were the organization’s financial statements audited by an independent accountant?

Yes

If ‘Yes,’ check a box below to indicate whether the financial statements for the year were audited on a separate basis, consolidated basis, or both:

Separate basis Consolidated basis Both consolidated and separate basis

If "Yes," to line 2a or 2b, does the organization have a committee that assumes responsibility for oversight of the audit, review, or compilation of its financial statements and selection of an independent accountant?

Yes

If the organization changed either its oversight process or selection process during the tax year, explain in Schedule O.

As a result of a federal award, was the organization required to undergo an audit or audits as set forth in the Uniform Guidance, 2 C.F.R. Part 200, Subpart F?

If "Yes," did the organization undergo the required audit or audits? If the organization did not undergo the required audit or audits, explain why in Schedule O and describe any steps taken to undergo such audits.

Form 990 (2024)

Additional Data

Software ID:
Software Version:

Form 990, Special Condition Description:

Special Condition Description

- TIN:

Schedule B
(Form 990)
(Rev. January 2025)

Department of the Treasury
Internal Revenue Service

Schedule of Contributors

Attach to Form 990, 990-EZ, or 990-PF.

Go to www.irs.gov/Form990 for the latest information.

OMB No. 1545-0047

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Organization type (check one):

Filers of:

Section:

Form 990 or 990-EZ

501(c)( ) (enter number) organization

4947(a)(1) nonexempt charitable trust not treated as a private foundation

527 political organization

Form 990-PF

501(c)(3) exempt private foundation

4947(a)(1) nonexempt charitable trust treated as a private foundation

501(c)(3) taxable private foundation

Check if your organization is covered by the General Rule or a Special Rule.
Note: Only a section 501(c)(7), (8), or (10) organization can check boxes for both the General Rule and a Special Rule. See instructions.

General Rule

For an organization filing Form 990, 990-EZ, or 990-PF that received, during the year, contributions totaling $5,000 or more (in money or other property) from any one contributor. Complete Parts I and II. See instructions for determining a contributor's total contributions.

Special Rules

For an organization described in section 501(c)(3) filing Form 990 or 990-EZ that met the 33¹/3% support test of the regulations
under sections 509(a)(1) and 170(b)(1)(A)(vi), that checked Schedule A (Form 990 or 990-EZ), Part II, line 13, 16a, or 16b, and that received from any one contributor, during the year, total contributions of the greater of (1) $5,000 or (2) 2% of the amount on (i) Form 990, Part VIII, line 1h, or (ii) Form 990-EZ, line 1. Complete Parts I and II.

For an organization described in section 501(c)(7), (8), or (10) filing Form 990 or 990-EZ that received from any one contributor,
during the year, total contributions of more than $1,000 exclusively for religious, charitable, scientific, literary, or educational purposes, or for the prevention of cruelty to children or animals. Complete Parts I, II, and III.

For an organization described in section 501(c)(7), (8), or (10) filing Form 990 or 990-EZ that received from any one contributor,
during the year, contributions exclusively for religious, charitable, etc., purposes, but no such contributions totaled more than $1,000. If this box is checked, enter here the total contributions that were received during the year for an exclusively religious, charitable, etc., purpose. Don't complete any of the parts unless the General Rule applies to this organization because it received nonexclusively religious, charitable, etc., contributions totaling $5,000 or more during the year ......... Right Arrow

Caution: An organization that isn't covered by the General Rule and/or the Special Rules doesn't file Schedule B (Form 990,
990-EZ, or 990-PF), but it must answer “No” on Part IV, line 2, of its Form 990; or check the box on line H of its Form 990-EZ
or on its Form 990PF, Part I, line 2, to certify that it doesn't meet the filing requirements of Schedule B (Form 990,
990-EZ, or 990-PF).

For Paperwork Reduction Act Notice, see the Instructions
for Form 990, 990-EZ, or 990-PF.

Cat. No. 30613XSchedule B (Form 990) (Rev. 1-2025)

Schedule B (Form 990) (Rev. 1-2025) Page 2

Name of organization AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Part I	Contributors (see instructions). Use duplicate copies of Part I if additional space is needed.
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
RESTRICTED	,	$ RESTRICTED	Person Payroll Noncash (Complete Part II for noncash contributions.)
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
		$	Person Payroll Noncash (Complete Part II for noncash contributions.)
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
		$	Person Payroll Noncash (Complete Part II for noncash contributions.)
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
		$	Person Payroll Noncash (Complete Part II for noncash contributions.)
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
		$	Person Payroll Noncash (Complete Part II for noncash contributions.)
(a) No.	(b) Name, address, and ZIP + 4	(c) Total contributions	(d) Type of contribution
		$	Person Payroll Noncash (Complete Part II for noncash contributions.)
Schedule B (Form 990) (Rev. 1-2025)

Schedule B (Form 990) (Rev. 1-2025)

Page 3

Name of organization AMERICAN SOCIETY FOR RADIATION ONCOLOGY		Employer identification number 42-0943164

Part II	Noncash Property (see instructions). Use duplicate copies of Part II if additional space is needed.
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
(a) No. from Part I	(b) Description of noncash property given	(c) FMV (or estimate) (See instructions)	(d) Date received
		$
Schedule B (Form 990) (Rev. 1-2025)

Schedule B (Form 990) (Rev. 1-2025)

Page 4


Name of organization AMERICAN SOCIETY FOR RADIATION ONCOLOGY			Employer identification number 42-0943164
Part III Exclusively religious, charitable, etc., contributions to organizations described in section 501(c) (7), (8), or (10) that total more than $1,000 for the year from any one contributor. Complete columns (a) through (e) and the following line entry. For organizations completing Part III, enter the total of exclusively religious, charitable, etc., contributions of $1,000 or less for the year. (Enter this information once. See instructions.) $ Use duplicate copies of Part III if additional space is needed.

(a)
No. from Part I

(b) Purpose of gift

(d) Description of how gift is held

(e) Transfer of gift
Transferee's name, address, and ZIP 4	Relationship of transferor to transferee

(a)
No. from Part I

(b) Purpose of gift

(d) Description of how gift is held

(e) Transfer of gift
Transferee's name, address, and ZIP 4	Relationship of transferor to transferee

(a)
No. from Part I

(b) Purpose of gift

(d) Description of how gift is held

(e) Transfer of gift
Transferee's name, address, and ZIP 4	Relationship of transferor to transferee

(a)
No. from Part I

(b) Purpose of gift

(d) Description of how gift is held

(e) Transfer of gift
Transferee's name, address, and ZIP 4	Relationship of transferor to transferee

Schedule B (Form 990) (Rev. 1-2025)

Additional Data

Software ID:
Software Version:

- TIN:

SCHEDULE C
(Form 990)

Department of the Treasury
Internal Revenue Service

Political Campaign and Lobbying Activities

For Organizations Exempt From Income Tax Under section 501(c) and section 527

right arrow

Complete if the organization is described below. right arrow

Attach to Form 990 or Form 990-EZ.
right arrow

Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

2024

Open to Public
Inspection

If the organization answered "Yes" on Form 990, Part IV, Line 3, or Form 990-EZ, Part V, line 46 (Political Campaign Activities), then
Round Bullet

Section 501(c)(3) organizations: Complete Parts I-A and B. Do not complete Part I-C.
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Section 501(c) (other than section 501(c)(3)) organizations: Complete Parts I-A and C below. Do not complete Part I-B.
Round Bullet

Section 527 organizations: Complete Part I-A only.
If the organization answered "Yes" on Form 990, Part IV, Line 4, or Form 990-EZ, Part VI, line 47 (Lobbying Activities), then
Round Bullet

Section 501(c)(3) organizations that have filed Form 5768 (election under section 501(h)): Complete Part II-A. Do not complete Part II-B.
Round Bullet

Section 501(c)(3) organizations that have NOT filed Form 5768 (election under section 501(h)): Complete Part II-B. Do not complete Part II-A.
If the organization answered "Yes" on Form 990, Part IV, Line 5 (Proxy Tax) (see separate instructions) or Form 990-EZ, Part V, line 35c (Proxy Tax) (see separate instructions), then
Round Bullet

Section 501(c)(4), (5), or (6) organizations: Complete Part III.

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Part I-A

Complete if the organization is exempt under section 501(c) or is a section 527 organization.

Provide a description of the organization’s direct and indirect political campaign activities in Part IV. See instructions for definition of “political campaign activities."

Political campaign activity expenditures. See instructions .................................................................... right arrow

Volunteer hours for political campaign activities. See instructions ..................................................................

Part I-B

Complete if the organization is exempt under section 501(c)(3).

Enter the amount of any excise tax incurred by the organization under section 4955 ................................ right arrow

Enter the amount of any excise tax incurred by organization managers under section 4955 ....................... right arrow

If the organization incurred a section 4955 tax, did it file Form 4720 for this year? .........................................

Yes No

Was a correction made? ......................................................................................................................

Yes No

If "Yes," describe in Part IV.

Part I-C

Complete if the organization is exempt under section 501(c), except section 501(c)(3).

Enter the amount directly expended by the filing organization for section 527 exempt function activities ..... right arrow

Enter the amount of the filing organization's funds contributed to other organizations for section 527 exempt function activities ............................................................................................................................ right arrow

Total exempt function expenditures. Add lines 1 and 2. Enter here and on Form 1120-POL, line 17b........... right arrow

Did the filing organization file Form 1120-POL for this year? ...................................................................

Yes No

Enter the names, addresses and employer identification number (EIN) of all section 527 political organizations to which the filing
organization made payments. For each organization listed, enter the amount paid from the filing organization’s funds. Also enter the amount of political contributions received that were promptly and directly delivered to a separate political organization, such as a separate segregated fund or a political action committee (PAC). If additional space is needed, provide information in Part IV.

(a) Name	(b) Address	(c) EIN	(d) Amount paid from filing organization's funds. If none, enter -0-.	(e) Amount of political contributions received and promptly and directly delivered to a separate political organization. If none, enter -0-.
(1) ASTRO PAC	251 18TH STREET SOUTH 8TH FLOOR ARLINGTON,VA22202	06-1673960	0	121,464
2
3
4
5
6

For Paperwork Reduction Act Notice, see the instructions for Form 990.

Cat. No. 50084S

Schedule C (Form 990) 2024

Page 2

Part II-A

Complete if the organization is exempt under section 501(c)(3) and filed Form 5768 (election under section 501(h)).

A Check right arrow

if the filing organization belongs to an affiliated group (and list in Part IV each affiliated group member's name, address, EIN, expenses, and share of excess lobbying expenditures).
B Check right arrow

if the filing organization checked box A and "limited control" provisions apply.

Limits on Lobbying Expenditures (The term "expenditures" means amounts paid or incurred.)		(b) Affiliated group totals
1a	Total lobbying expenditures to influence public opinion (grass roots lobbying) ......................
b	Total lobbying expenditures to influence a legislative body (direct lobbying) ........................
c	Total lobbying expenditures (add lines 1a and 1b) ............................................................
d	Other exempt purpose expenditures ...............................................................................
e	Total exempt purpose expenditures (add lines 1c and 1d) ..................................................
f	Lobbying nontaxable amount. Enter the amount from the following table in both columns.
	If the amount on line 1e, column (a) or (b) is:The lobbying nontaxable amount is:
	Not over $500,00020% of the amount on line 1e.
	Over $500,000 but not over $1,000,000$100,000 plus 15% of the excess over $500,000.
	Over $1,000,000 but not over $1,500,000$175,000 plus 10% of the excess over $1,000,000.
	Over $1,500,000 but not over $17,000,000$225,000 plus 5% of the excess over $1,500,000.
	Over $17,000,000$1,000,000.

g	Grassroots nontaxable amount (enter 25% of line 1f) .................................................
h	Subtract line 1g from line 1a. If zero or less, enter -0-. ................................................
i	Subtract line 1f from line 1c. If zero or less, enter -0-. ................................................
j	If there is an amount other than zero on either line 1h or line 1i, did the organization file Form 4720 reporting section 4911 tax for this year? ...................................................................................................................	Yes No

4-Year Averaging Period Under Section 501(h) (Some organizations that made a section 501(h) election do not have to complete all of the five columns below. See the separate instructions for lines 2a through 2f.)
Lobbying Expenditures During 4-Year Averaging Period
	Calendar year (or fiscal year beginning in)	(a) 2021	(b) 2022	(c) 2023	(d) 2024	(e) Total

2a	Lobbying nontaxable amount

b	Lobbying ceiling amount (150% of line 2a, column(e))

c	Total lobbying expenditures

d	Grassroots nontaxable amount

e	Grassroots ceiling amount (150% of line 2d, column (e))

f	Grassroots lobbying expenditures

Schedule C (Form 990) 2024

Page 3

Part II-B

Complete if the organization is exempt under section 501(c)(3) and has NOT filed Form 5768 (election under section 501(h)).

For each "Yes" response on lines 1a through 1i below, provide in Part IV a detailed description of the lobbying activity.

(a)

Yes

(b)

Amount

During the year, did the filing organization attempt to influence foreign, national, state or local legislation, including any attempt to influence public opinion on a legislative matter or referendum, through the use of:

Volunteers? ...........................................................................................................

Paid staff or management (include compensation in expenses reported on lines 1c through 1i)? ........

Media advertisements? ...................................................................................................

Mailings to members, legislators, or the public? .............................................................................

Publications, or published or broadcast statements? ...........................................................

Grants to other organizations for lobbying purposes? ..........................................................

Direct contact with legislators, their staffs, government officials, or a legislative body? .......................

Rallies, demonstrations, seminars, conventions, speeches, lectures, or any similar means? ..................

Other activities? ...................................................................................................................

Total. Add lines 1c through 1i ....................................................................................................

Did the activities in line 1 cause the organization to be not described in section 501(c)(3)? .....

If "Yes," enter the amount of any tax incurred under section 4912 ...........................................

If "Yes," enter the amount of any tax incurred by organization managers under section 4912 ...................

If the filing organization incurred a section 4912 tax, did it file Form 4720 for this year? ........................

Part III-A

Complete if the organization is exempt under section 501(c)(4), section 501(c)(5), or section 501(c)(6).

Yes

Were substantially all (90% or more) dues received nondeductible by members? ...............................................

Did the organization make only in-house lobbying expenditures of $2,000 or less? ............................................

Did the organization agree to carry over lobbying and political expenditures from the prior year? .................................

Yes

Part III-B

Complete if the organization is exempt under section 501(c)(4), section 501(c)(5), or section 501(c)(6) and if either (a) BOTH Part III-A, lines 1 and 2, are answered "No" OR (b) Part III-A, line 3, is answered “Yes."

Dues, assessments and similar amounts from members ......................................................................

4,223,885

Section 162(e) nondeductible lobbying and political expenditures (do not include amounts of political expenses for which the section 527(f) tax was paid).

Current year .............................................................................................................................

810,818

Carryover from last year ............................................................................................................

-21,847

Total ...........................................................................................................................................

788,971

Aggregate amount reported in section 6033(e)(1)(A) notices of nondeductible section 162(e) dues .

887,016

If notices were sent and the amount on line 2c exceeds the amount on line 3, what portion of the excess does the organization agree to carryover to the reasonable estimate of nondeductible lobbying and political expenditure next year? ......................................................................................................................

-98,045

Taxable amount of lobbying and political expenditures. See Instructions .........................................

Part IV

Supplemental Information

Provide the descriptions required for Part l-A, line 1; Part l-B, line 4; Part l-C, line 5; Part II-A (affiliated group list); Part II-A, lines 1 and 2 (see instructions), and Part ll-B, line 1. Also, complete this part for any additional information.

Return Reference	Explanation

Schedule C (Form 990) 2024

Additional Data

Software ID:
Software Version:

- TIN:

SCHEDULE D
(Form 990)

Department of the Treasury
Internal Revenue Service

Supplemental Financial Statements

Complete if the organization answered "Yes," on Form 990,
Part IV, line 6, 7, 8, 9, 10, 11a, 11b, 11c, 11d, 11e, 11f, 12a, or 12b.
right arrow

Attach to Form 990.
right arrow

Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

Open to Public Inspection

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Part I

Organizations Maintaining Donor Advised Funds or Other Similar Funds or Accounts. Complete if the organization answered "Yes" on Form 990, Part IV, line 6.

		(a) Donor advised funds	(b) Funds and other accounts
1	Total number at end of year .........
2	Aggregate value of contributions to (during year)
3	Aggregate value of grants from (during year)
4	Aggregate value at end of year ........

Did the organization inform all donors and donor advisors in writing that the assets held in donor advised funds are the organization’s property, subject to the organization’s exclusive legal control? ............

Yes No

Did the organization inform all grantees, donors, and donor advisors in writing that grant funds can be used only for charitable purposes and not for the benefit of the donor or donor advisor, or for any other purpose conferring impermissible private benefit? ...................................

Yes No

Part II

Conservation Easements.
Complete if the organization answered "Yes" on Form 990, Part IV, line 7.

Purpose(s) of conservation easements held by the organization (check all that apply).

Preservation of land for public use (e.g., recreation or education) Preservation of an historically important land area

Protection of natural habitat Preservation of a certified historic structure

Preservation of open space

Complete lines 2a through 2d if the organization held a qualified conservation contribution in the form of a conservation easement on the last day of the tax year.


a	Total number of conservation easements ......................	2a
b	Total acreage restricted by conservation easements ....................	2b
c	Number of conservation easements on a certified historic structure included in (a) .....	2c
d	Number of conservation easements included in (c) acquired after July 25, 2006, and not on a historic structure listed in the National Register ...	2d

Number of conservation easements modified, transferred, released, extinguished, or terminated by the organization during the
tax year right arrow

Number of states where property subject to conservation easement is located right arrow

Does the organization have a written policy regarding the periodic monitoring, inspection, handling of violations, and enforcement of the conservation easements it holds? ............

Yes No

Staff and volunteer hours devoted to monitoring, inspecting, handling of violations, and enforcing conservation easements during the year
right arrow

Amount of expenses incurred in monitoring, inspecting, handling of violations, and enforcing conservation easements during the year
right arrow

Does each conservation easement reported on line 2(d) above satisfy the requirements of section 170(h)(4)(B)(i) and section 170(h)(4)(B)(ii)? .............................

Yes No

In Part XIII, describe how the organization reports conservation easements in its revenue and expense statement, and
balance sheet, and include, if applicable, the text of the footnote to the organization’s financial statements that describes
the organization’s accounting for conservation easements.

Part III

Organizations Maintaining Collections of Art, Historical Treasures, or Other Similar Assets.
Complete if the organization answered "Yes" on Form 990, Part IV, line 8.

If the organization elected, as permitted under FASB ASC 958, not to report in its revenue statement and balance sheet works of art, historical treasures, or other similar assets held for public exhibition, education, or research in furtherance of public service, provide, in Part XIII, the text of the footnote to its financial statements that describes these items.

If the organization elected, as permitted under FASB ASC 958, to report in its revenue statement and balance sheet works of art, historical treasures, or other similar assets held for public exhibition, education, or research in furtherance of public service, provide the following amounts relating to these items:

(i)

Revenue included on Form 990, Part VIII, line 1 ......................... right arrow

(ii)

Assets included in Form 990, Part X ............................... right arrow

If the organization received or held works of art, historical treasures, or other similar assets for financial gain, provide the
following amounts required to be reported under FASB ASC 958 relating to these items:

Revenue included on Form 990, Part VIII, line 1 .......................... right arrow

Assets included in Form 990, Part X ............................... right arrow

For Paperwork Reduction Act Notice, see the Instructions for Form 990.

Cat. No. 52283D

Schedule D (Form 990) (Rev. 1-2025)

Page 2

Part III

Organizations Maintaining Collections of Art, Historical Treasures, or Other Similar Assets (continued)

Using the organization’s acquisition, accession, and other records, check any of the following that are a significant use of its collection items (check all that apply):

Public exhibition

Loan or exchange programs

Scholarly research

Other

Preservation for future generations

Provide a description of the organization’s collections and explain how they further the organization’s exempt purpose in
Part XIII.

During the year, did the organization solicit or receive donations of art, historical treasures or other similar
assets to be sold to raise funds rather than to be maintained as part of the organization’s collection?...

Yes No

Part IV

Escrow and Custodial Arrangements. Complete if the organization answered "Yes" on Form 990, Part IV, line 9, or reported an amount on Form 990, Part X, line 21.

Is the organization an agent, trustee, custodian or other intermediary for contributions or other assets not
included on Form 990, Part X? ....................................

Yes No


b	If "Yes," explain the arrangement in Part XIII and complete the following table:		Amount
c	Beginning balance .............................	1c
d	Additions during the year ............................	1d
e	Distributions during the year ..........................	1e
f	Ending balance ................................	1f

Did the organization include an amount on Form 990, Part X, line 21, for escrow or custodial account liability? ...

Yes No

If "Yes," explain the arrangement in Part XIII. Check here if the explanation has been provided in Part XIII ....

Part V

Endowment Funds.
Complete if the organization answered "Yes" on Form 990, Part IV, line 10.

		(a) Current year	(b) Prior year	(c) Two years back	(d) Three years back	(e) Four years back

1a	Beginning of year balance ....	19,075,413	18,836,551	17,530,658	18,718,627	18,375,812
b	Contributions ...	1,402,289	659,508	1,844,908	45,000	553,321
c	Net investment earnings, gains, and losses
d	Grants or scholarships ...
e	Other expenditures for facilities and programs ...	906,525	420,646	539,015	1,232,969	210,506
f	Administrative expenses ....
g	End of year balance ......	19,571,177	19,075,413	18,836,551	17,530,658	18,718,627

Provide the estimated percentage of the current year end balance (line 1g, column (a)) held as:

Board designated or quasi-endowment right arrow

100.000 %

Permanent endowment right arrow

Term endowment right arrow

The percentages on lines 2a, 2b, and 2c should equal 100%.

Are there endowment funds not in the possession of the organization that are held and administered for the
organization by:

Yes

(i) Unrelated organizations .................

3a(i)

(ii) Related organizations .................

3a(ii)

If "Yes" on 3a(ii), are the related organizations listed as required on Schedule R? .........

Describe in Part XIII the intended uses of the organization's endowment funds.

Part VI

Land, Buildings, and Equipment.
Complete if the organization answered "Yes" on Form 990, Part IV, line 11a. See Form 990, Part X, line 10.

Description of property		(a) Cost or other basis (investment)	(b) Cost or other basis (other)	(c) Accumulated depreciation	(d) Book value

1a	Land .....
b	Buildings ....
c	Leasehold improvements	2,402,956	1,702,099	700,857
d	Equipment ....	720,747	678,717	42,030
e	Other .....	2,542,149	2,542,149	0
Total. Add lines 1a through 1e. (Column (d) must equal Form 990, Part X, column (B), line 10(c).)..				742,887

Schedule D (Form 990) (Rev. 1-2025)

Page 3

Part VII

Investments - Other Securities.
Complete if the organization answered "Yes" on Form 990, Part IV, line 11b. See Form 990, Part X, line 12.

(a) Description of security or category (including name of security)	(b) Book value	(c) Method of valuation: Cost or end-of-year market value
(1) Financial derivatives.........
(2) Closely-held equity interests........
(3) Other (A) TA REALTY CORE PROPERTY FUND	1,743,520	F
(B) GOLDMAN SACHS VINTAGE VIII SCSP	933,475	F
(C) PARTNERS GROUP PRIVATE EQUITY MASTER FUND	1,001,778	F
(D) PE BLACKSTONE TACT. OPPS. III	944,716	F
(E) FORTRESS LENDING FUND II(A)	478,340	F
(F) BLACKSTONE REIT	361,823	F
(G) ENTRUST SPECIAL OPPS. FUND III	409,157	F
(H) SKYBRIDGE MULTI-ADVISER HEDGE	284,062	F
(I) GOLDMAN SACHS VINTAGE VI LP	174,428	F
(J) BLACKSTONE REIT CI I	1,477	F
Total. (Column (b) must equal Form 990, Part X, col. (B) line 12.)	6,332,776

Part VIII

Investments - Program Related. Complete if the organization answered 'Yes' on Form 990, Part IV, line 11c. See Form 990, Part X, line 13.

(a) Description of investment	(b) Book value	(c) Method of valuation: Cost or end-of-year market value

(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Total. (Column (b) must equal Form 990, Part X, col.(B) line 13.)

Part IX

Other Assets.
Complete if the organization answered 'Yes' on Form 990, Part IV, line 11d. See Form 990, Part X, line 15.

(a) Description				(b) Book value
(1)OPERATING RIGHT-OF-USE ASSET				2,027,263
(2)DEFERRED COMPENSATION INVESTMENTS				726,966
(3)DEPOSITS				162,811
(3)
(4)
(5)
(6)
(7)
(8)
(9)
Total. (Column (b) must equal Form 990, Part X, col.(B) line 15.)...........				2,917,040

Part X

Other Liabilities.
Complete if the organization answered 'Yes' on Form 990, Part IV, line 11e or 11f. See Form 990, Part X, line 25.

1.(a) Description of liability	(b) Book value
(1) Federal income taxes
OPERATING LEASE LIABILITY	3,282,399
DEFERRED COMPENSATION LIABILITY	726,969
DUE TO AFFILIATES	31,259






Total. (Column (b) must equal Form 990, Part X, col.(B) line 25.)	4,040,627
2. Liability for uncertain tax positions. In Part XIII, provide the text of the footnote to the organization's financial statements that reports the organization's liability for uncertain tax positions under FIN 48 (ASC 740). Check here if the text of the footnote has been provided in Part XIII

Schedule D (Form 990) (Rev. 1-2025)

Page 4

Part XI Reconciliation of Revenue per Audited Financial Statements With Revenue per Return. Complete if the organization answered 'Yes' on Form 990, Part IV, line 12a.
1	Total revenue, gains, and other support per audited financial statements .......			1	28,604,955
2	Amounts included on line 1 but not on Form 990, Part VIII, line 12:
a	Net unrealized gains (losses) on investments ....	2a	3,410,567
b	Donated services and use of facilities .........	2b
c	Recoveries of prior year grants ...........	2c
d	Other (Describe in Part XIII.) ...........	2d
e	Add lines 2a through 2d .....................			2e	3,410,567
3	Subtract line 2e from line 1..................			3	25,194,388
4	Amounts included on Form 990, Part VIII, line 12, but not on line 1:
a	Investment expenses not included on Form 990, Part VIII, line 7b .	4a	94,662
b	Other (Describe in Part XIII.) ...........	4b	-4,272
c	Add lines 4a and 4b....................			4c	90,390
5	Total revenue. Add lines 3 and 4c. (This must equal Form 990, Part I, line 12.) ......			5	25,284,778

Part XII Reconciliation of Expenses per Audited Financial Statements With Expenses per Return. Complete if the organization answered 'Yes' on Form 990, Part IV, line 12a.
1	Total expenses and losses per audited financial statements ...........			1	25,354,495
2	Amounts included on line 1 but not on Form 990, Part IX, line 25:
a	Donated services and use of facilities .........	2a
b	Prior year adjustments ............	2b
c	Other losses ................	2c
d	Other (Describe in Part XIII.) ...........	2d	4,272
e	Add lines 2a through 2d....................			2e	4,272
3	Subtract line 2e from line 1...................			3	25,350,223
4	Amounts included on Form 990, Part IX, line 25, but not on line 1:
a	Investment expenses not included on Form 990, Part VIII, line 7b ..	4a	94,662
b	Other (Describe in Part XIII.) ...........	4b
c	Add lines 4a and 4b.....................			4c	94,662
5	Total expenses. Add lines 3 and 4c. (This must equal Form 990, Part I, line 18.) ......			5	25,444,885

Part XIII

Supplemental Information

Provide the descriptions required for Part II, lines 3, 5, and 9; Part III, lines 1a and 4; Part lV, lines 1b and 2b; Part V, line 4; Part X, line 2; Part XI, lines 2d and 4b; and Part XII, lines 2d and 4b. Also complete this part to provide any additional information.

Return Reference	Explanation
PART V, LINE 4:	ASTRO WILL USE THESE ENDOWMENT FUNDS FOR SPECIFIC PROGRAMS AND ACTIVITES AS DESIGNATED BY THE BOARD OF DIRECTORS.
PART X, LINE 2:	ASTRO PERFORMED AN EVALUATION OF UNCERTAINTY IN INCOME TAXES FOR THE YEAR ENDED DECEMBER 31, 2024, AND DETERMINED THAT THERE ARE NO MATTERS THAT WOULD REQUIRE RECOGNITION IN THE CONSOLIDATED FINANCIAL STATEMENTS OR THAT MAY HAVE ANY EFFECT ON ITS TAX-EXEMPT STATUS.
PART XI, LINE 4B - OTHER ADJUSTMENTS:	COST OF GOODS SOLD -4,272.
PART XII, LINE 2D - OTHER ADJUSTMENTS:	COST OF GOODS SOLD 4,272.
PART XII, LINE 2B	PRIOR YEAR ADJUSTMENTS INCLUDE REFUNDS OF UNUSED FUNDS FROM PRIOR YEAR GRANTS.

Schedule D (Form 990) (Rev. 1-2025)

Additional Data

Software ID:
Software Version:

- TIN:

Note: To capture the full content of this document, please select landscape mode (11" x 8.5") when printing.

Schedule I
(Form 990)
(Rev. January 2025)

Department of the Treasury
Internal Revenue Service

Grants and Other Assistance to Organizations,
Governments and Individuals in the United States

Complete if the organization answered "Yes," on Form 990, Part IV, line 21 or 22.
lBullet

Attach to Form 990.
lBullet

Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

Open to Public
Inspection

Name of the organization
AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number
42-0943164

Part I

General Information on Grants and Assistance

Does the organization maintain records to substantiate the amount of the grants or assistance, the grantees' eligibility for the grants or assistance, and
the selection criteria used to award the grants or assistance? ........................

Yes No

Describe in Part IV the organization's procedures for monitoring the use of grant funds in the United States.

Part II

Grants and Other Assistance to Domestic Organizations and Domestic Governments. Complete if the organization answered "Yes" on Form 990, Part IV, line 21, for any recipient

that received more than $5,000. Part II can be duplicated if additional space is needed.

(a) Name and address of organization or government	(b) EIN	(c) IRC section (if applicable)	(d) Amount of cash grant	(h) Purpose of grant or assistance
(1) CITY OF HOPE 1500 EAST DUARTE ROAD DUARTE,CA91010	95-3435919	501(C)(3)	12,500	RESEARCH GRANT AWARD
(2) STANFORD UNIVERSITY 485 BROADWAY 3RD FLOOR REDWOOD CITY,CA94063	94-1156365	501(C)(3)	12,500	RESEARCH GRANT AWARD
(3) RADIATION ONCOLOGY INSTITUTE 251 18TH STREET SOUTH 8TH FLOOR ARLINGTON,VA22202	51-0178702	501(C)(3)	14,463	ASTRO MATCH
(4) TOUCH4LIFE INC 6030 DAYBREAK CIR CLARKSVILLE,MD21029	84-4901951	501(C)(3)	12,500	SURVIVOR CIRCLE AWARD
(5) SMITH CENTER FOR HEALING AND THE ARTS 1632 U STREET NW WASHINGTON,DC20009	52-1977976	501(C)(3)	12,500	SURVIVOR CIRCLE AWARD
(6) DUKE UNIVERSITY PO BOX 104132 DURHAM,NC27708	56-0532129	501(C)(3)	25,000	RESEARCH GRANT AWARD
(7) AMERICAN CANCER SOCIETY INC 270 PEACHTREE ST NW ATLANTA,GA30303	13-1788491	501(C)(3)	312,500	RESEARCH GRANT AWARD
(8) YALE UNIVERSITY PO BOX 1873 NEW HAVEN,CT06508	06-0646973	501(C)(3)	25,000	RESEARCH GRANT AWARD
(9) AMERICAN ASSOCIATION OF PHYSICISTS IN MEDICINE 1631 PRINCE STREET ALEXANDRIA,VA22314	23-7057224	501(C)(3)	25,000	RESEARCH GRANT AWARD
(10) THE FEINSTEIN INSTITUTES FOR MEDICAL RESEARCH 72 BRUSH HOLLOW ROAD WESTBURY,NY11590	11-2673595	501(C)(3)	101,040	RESEARCH GRANT AWARD
(11) MELANOMA RESEARCH ALLIANCE 730 15TH STREET NW WASHINGTON,DC20005	26-1636099	501(C)(3)	127,500	RESEARCH GRANT AWARD
(12) NRG ONCOLOGY FOUNDATION 1600 JOHN F KENNEDY BLVD PHILADELPHIA,PA19103	90-0912747	501(C)(3)	25,000	RESEARCH GRANT AWARD

Enter total number of section 501(c)(3) and government organizations listed in the line 1 table ................. Bullet Image

Enter total number of other organizations listed in the line 1 table ........................ . Bullet Image

For Paperwork Reduction Act Notice, see the Instructions for Form 990.

Cat. No. 50055P

Schedule I (Form 990) Rev. 1-2025

Page 2

Part III

Grants and Other Assistance to Domestic Individuals. Complete if the organization answered "Yes" on Form 990, Part IV, line 22.
Part III can be duplicated if additional space is needed.

(a) Type of grant or assistance	(b) Number of recipients	(c) Amount of cash grant	(d) Amount of noncash assistance	(e) Method of valuation (book, FMV, appraisal, other)	(f) Description of noncash assistance

(1)
(2)
(3)
(4)
(5)
(6)
(7)

Part IV

Supplemental Information. Provide the information required in Part I, line 2; Part III, column (b); and any other additional information.

Return Reference	Explanation
PART I, LINE 2:	ASTRO FUNDS RESEARCH FOR JUNIOR FACULTY, RESIDENTS, FELLOWS, AND POSTDOCTORAL FELLOWS IN SUPPORT OF RADIATION ONCOLOGY RESEARCHERS' CAREERS. ASTRO AWARD GRANTS REQUIRE SPECIFIC DELIVERABLES (SUCH AS ANNUAL WRITTEN PROGRESS REPORTS AND A FINAL WRITTEN REPORT) TO ENSURE THAT THE FUNDS HAVE BEEN USED TO ACCOMPLISH A DEFINED PURPOSE OF THE GRANT.

Schedule I (Form 990) Rev. 1-2025

Additional Data

Software ID:
Software Version:

- TIN:

Schedule J
(Form 990)
(Rev. January 2025)

Department of the Treasury
Internal Revenue Service

Compensation Information

For certain Officers, Directors, Trustees, Key Employees, and Highest
Compensated Employees
medium right arrow graphic

Complete if the organization answered "Yes" on Form 990, Part IV, line 23.
medium right arrow graphic

Attach to Form 990.
medium right arrow graphic

Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

Open to Public Inspection

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Part I

Questions Regarding Compensation

Yes

Check the appropiate box(es) if the organization provided any of the following to or for a person listed on Form
990, Part VII, Section A, line 1a. Complete Part III to provide any relevant information regarding these items.

First-class or charter travel Housing allowance or residence for personal use

Travel for companions Payments for business use of personal residence

Tax idemnification and gross-up payments Health or social club dues or initiation fees

Discretionary spending account Personal services (e.g., maid, chauffeur, chef)

If any of the boxes on Line 1a are checked, did the organization follow a written policy regarding payment or reimbursement or provision of all of the expenses described above? If "No," complete Part III to explain .....

Yes

Did the organization require substantiation prior to reimbursing or allowing expenses incurred by all
directors, trustees, officers, including the CEO/Executive Director, regarding the items checked on Line 1a? ....

Yes

Indicate which, if any, of the following the filing organization used to establish the compensation of the
organization's CEO/Executive Director. Check all that apply. Do not check any boxes for methods
used by a related organization to establish compensation of the CEO/Executive Director, but explain in Part III.

Compensation committee Written employment contract

Independent compensation consultant Compensation survey or study

Form 990 of other organizations Approval by the board or compensation committee

During the year, did any person listed on Form 990, Part VII, Section A, line 1a, with respect to the filing organization or a related organization:

Receive a severance payment or change-of-control payment? .............

Participate in, or receive payment from, a supplemental nonqualified retirement plan? .........

Yes

Participate in, or receive payment from, an equity-based compensation arrangement? .........

If "Yes" to any of lines 4a-c, list the persons and provide the applicable amounts for each item in Part III.

Only 501(c)(3), 501(c)(4), and 501(c)(29) organizations must complete lines 5-9.

For persons listed on Form 990, Part VII, Section A, line 1a, did the organization pay or accrue any
compensation contingent on the revenues of:

The organization? ....................

Any related organization? .......................

If "Yes," on line 5a or 5b, describe in Part III.

For persons listed on Form 990, Part VII, Section A, line 1a, did the organization pay or accrue any
compensation contingent on the net earnings of:

The organization? ..................

Any related organization? ......................

If "Yes," on line 6a or 6b, describe in Part III.

For persons listed on Form 990, Part VII, Section A, line 1a, did the organization provide any nonfixed
payments not described in lines 5 and 6? If "Yes," describe in Part III ............

Were any amounts reported on Form 990, Part VII, paid or accured pursuant to a contract that was
subject to the initial contract exception described in Regulations section 53.4958-4(a)(3)? If "Yes," describe
in Part III ..........................

If "Yes" on line 8, did the organization also follow the rebuttable presumption procedure described in Regulations section 53.4958-6(c)? .........................

For Paperwork Reduction Act Notice, see the Instructions for Form 990.

Cat. No. 50053T

Schedule J (Form 990) (Rev. 1-2025)

Page 2

Part II

Officers, Directors, Trustees, Key Employees, and Highest Compensated Employees. Use duplicate copies if additional space is needed.

For each individual whose compensation must be reported on Schedule J, report compensation from the organization on row (i) and from related organizations, described in the
instructions, on row (ii). Do not list any individuals that are not listed on Form 990, Part VII.
Note. The sum of columns (B)(i)-(iii) for each listed individual must equal the total amount of Form 990, Part VII, Section A, line 1a, applicable column (D) and (E) amounts for that individual.

(A) Name and Title		(B) Breakdown of W-2, 1099-MISC compensation, and/or 1099-NEC			(C) Retirement and other deferred compensation	(D) Nontaxable benefits	(E) Total of columns (B)(i)-(D)	(F) Compensation in column (B) reported as deferred on prior Form 990
(A) Name and Title		(i) Base compensation	(ii) Bonus & incentive compensation	(iii) Other reportable compensation	(C) Retirement and other deferred compensation	(D) Nontaxable benefits	(E) Total of columns (B)(i)-(D)
1LAURA I THEVENOT CEO UNTIL 11/24	(i) (ii)	609,347 ------------- 0	124,274 ------------- 0	71,664 ------------- 0	45,500 ------------- 0	23,593 ------------- 0	874,378 ------------- 0	0 ------------- 0
2EMILY WILSON EXECUTIVE VICE PRESIDENT	(i) (ii)	307,548 ------------- 0	13,000 ------------- 0	0 ------------- 0	32,557 ------------- 0	14,964 ------------- 0	368,069 ------------- 0	0 ------------- 0
3DAVE ADLER VP, ADVOCACY & CLINICAL AFFAIRS	(i) (ii)	244,371 ------------- 0	5,000 ------------- 0	0 ------------- 0	26,096 ------------- 0	32,510 ------------- 0	307,977 ------------- 0	0 ------------- 0
4LAURA GOGAL GENERAL COUNSEL	(i) (ii)	241,543 ------------- 0	1,000 ------------- 0	0 ------------- 0	24,606 ------------- 0	20,581 ------------- 0	287,730 ------------- 0	0 ------------- 0
5ANNE HUBBARD DIRECTOR OF HEALTH POLICY	(i) (ii)	225,661 ------------- 0	2,000 ------------- 0	0 ------------- 0	23,867 ------------- 0	31,382 ------------- 0	282,910 ------------- 0	0 ------------- 0
6TERRY KARRAS CFO	(i) (ii)	218,931 ------------- 0	4,500 ------------- 0	0 ------------- 0	23,112 ------------- 0	31,810 ------------- 0	278,353 ------------- 0	0 ------------- 0
7CHRIS NEUMANN VP, EDUCATION	(i) (ii)	174,046 ------------- 0	2,000 ------------- 0	0 ------------- 0	18,868 ------------- 0	31,111 ------------- 0	226,025 ------------- 0	0 ------------- 0
8ANNA ARNONE VP, MEMBERSHIP & COMMUNICATION	(i) (ii)	196,677 ------------- 0	2,000 ------------- 0	750 ------------- 0	19,561 ------------- 0	2,867 ------------- 0	221,855 ------------- 0	0 ------------- 0
9SAMANTHA DAWES DIRECTOR OF QUALITY IMPROVEMENT	(i) (ii)	189,409 ------------- 0	3,000 ------------- 0	0 ------------- 0	19,188 ------------- 0	1,978 ------------- 0	213,575 ------------- 0	0 ------------- 0
10KIRSTA SUGGS DIRECTOR OF HACE	(i) (ii)	176,957 ------------- 0	2,000 ------------- 0	0 ------------- 0	18,134 ------------- 0	13,249 ------------- 0	210,340 ------------- 0	0 ------------- 0
11JEFF WHITE DIRECTOR OF PUBLIC RELATIONS	(i) (ii)	169,364 ------------- 0	2,000 ------------- 0	0 ------------- 0	17,117 ------------- 0	13,318 ------------- 0	201,799 ------------- 0	0 ------------- 0

Schedule J (Form 990) (Rev. 1-2025)

Page 3

Part III

Supplemental Information

Provide the information, explanation, or descriptions required for Part I, lines 1a, 1b, 3, 4a, 4b, 4c, 5a, 5b, 6a, 6b, 7, and 8, and for Part II. Also complete this part for any additional information.

Return Reference	Explanation
PART I, LINE 1A	FORMER BOARD MEMBER PAUL M HARARI RECEIVED TRAVEL EXPENSE REIMBURSEMENT FOR FIRST-CLASS TRAVEL AND COMPANION TRAVEL EXPENSES IN 2024.
PART I, LINE 4B	DURING THE YEAR ENDED DECEMBER 31, 2024, LAURA THEVENOT, CEO UNTIL 11/24, PARTICIPATED IN A 457(F) NONQUALIFIED PLAN, WITH CONTRIBUTIONS TO THE PLAN OF $11,000.

Schedule J (Form 990) (Rev. 1-2025)

Additional Data

Software ID:
Software Version:

- TIN:

SCHEDULE O
(Form 990)
(Rev. January 2025)
Department of the Treasury
Internal Revenue Service

Supplemental Information to Form 990 or 990-EZ

Complete to provide information for responses to specific questions on
Form 990 or 990-EZ or to provide any additional information.
Attach to Form 990 or 990-EZ.
Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

Open to Public
Inspection

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Return Reference	Explanation
FORM 990, PART VI, SECTION A, LINE 4	THE CHANGES INCLUDE REVISING THE AFFILIATE MEMBER CATEGORY DESCRIPTION TO MAKE IT FOR NON-RADIATION ONCOLOGISTS; LIMITING THE NUMBER OF BOARD MEMBERS FROM ONE INSTITUTION SERVING ON THE BOARD AT THE SAME TIME TO A MAXIMUM OF TWO; AND INCREASING THE NUMBER OF SUPPORTING SIGNATURES NEEDED FOR MEMBER NOMINATIONS TO BE INCLUDED ON THE BALLOT FOR ELECTIONS TO MAKE IT PROPORTIONAL WITH THE NUMBER OF MEMBERS.
FORM 990, PART VI, SECTION A, LINE 6	ASTRO MEMBERSHIP IS DIVIDED INTO NINE CATEGORIES: ACTIVE, AFFILIATE, INTERNATIONAL, ASSOCIATE, POSTDOCTORAL FELLOW, MEMBER-IN-TRAINING, STUDENT/GRADUATE STUDENT/PGY-1, EMERITUS, AND HONORARY.
FORM 990, PART VI, SECTION A, LINE 7A	ONLY ACTIVE, AFFILIATE, AND INTERNATIONAL MEMBERS HAVE THE RIGHT TO VOTE AT MEMBERSHIP MEETINGS. FURTHERMORE, ONLY ACTIVE MEMBERS WHO ARE BOARD CERTIFIED BY THE ABR OR EQUIVALENT HAVE THE RIGHT TO HOLD ELECTIVE OFFICE. THE VOTING MEMBERSHIP OF THE SOCIETY SHALL ELECT BOARD MEMBERS AND NOMINATING COMMITTEE MEMBERS, AND AS NECESSARY, REPLACEMENTS TO FILL ANY VACANCIES OCCURRING IN ELECTED OFFICES DUE TO DEATH, RESIGNATION, REMOVAL, OR ASSUMPTION OF HIGHER OFFICE.
FORM 990, PART VI, SECTION A, LINE 7B	AMENDMENT TO THE BYLAWS, AND CHANGES TO MEMBERSHIP DUES AND APPLICATION FEES REQUIRES THE APPROVAL OF THE MEMBERSHIP OF THE SOCIETY THROUGH A SECRET BALLOT VOTE. NO SPECIAL ASSESSMENT CAN BE LEVIED ON THE MEMBERS OF THE SOCIETY EXCEPT UPON RECOMMENDATION OF THE BOARD OF DIRECTORS AND APPROVAL BY THE MEMBERSHIP OF THE SOCIETY THROUGH A SECRET BALLOT VOTE.
FORM 990, PART VI, SECTION B, LINE 11B	THE FEDERAL FORM 990 IS PREPARED BY OUR EXTERNAL TAX ACCOUNTANTS. THE DRAFT IS PROVIDED TO OUR FINANCE STAFF FOR REVIEW BEFORE BEING SUBMITTED TO THE VP FINANCE & ADMINISTRATION, CEO, AND TREASURER FOR THEIR REVIEW AND APPROVAL. THE REVISED DRAFT IS THEN PROVIDED TO THE FULL BOARD OF DIRECTORS FOR THEIR REVIEW PRIOR TO FILING WITH THE INTERNAL REVENUE SERVICE.
FORM 990, PART VI, SECTION B, LINE 12C	ASTRO'S OFFICERS, DIRECTORS, KEY EMPLOYEES AND VOLUNTEERS ARE REQUIRED TO FILL OUT DISCLOSURE FORMS ON AN ANNUAL BASIS AND TO UPDATE THEIR DISCLOSURE FORMS UPON ANY MATERIAL CHANGE IN THE INTERIM. THESE DISCLOSURE FORMS ARE REVIEWED IN ORDER TO IDENTIFY AND ADDRESS ANY POTENTIAL CONFLICTS OF INTERESTS FOR THESE INDIVIDUALS.
FORM 990, PART VI, SECTION B, LINE 15	AN INDEPENDENT CONSULTANT PERFORMED MARKET SURVEY TO DEVELOP SALARY STRUCTURE AND RANGES. ASTRO'S PRACTICE IS TO COMPLETE A MARKET SURVEY EVERY THREE YEARS. THE CEO'S COMPENSATION IS DETERMINED BY A SUBCOMMITTEE OF THE BOARD USING COMPARABLE SALARIES OF SIMILAR CEO POSITIONS OF NONPROFIT MEDICAL ORGANIZATIONS. THIS REVIEW WAS DISCUSSED WITH THE BOARD OF DIRECTORS AND RECEIVED THEIR APPROVAL. ANNUALLY, BUDGET GUIDELINES ARE SET FOR ANY ADDITIONS TO STAFF AND SALARY INCREASES. MANAGERS MAKE RECOMMENDATIONS FOR ANNUAL INCREASES AND PROMOTIONS WHICH ARE REVIEWED BY HUMAN RESOURCES AND DIVISION VICE PRESIDENTS. ALL PROMOTIONS ARE APPROVED BY THE CHIEF EXECUTIVE OFFICER.
FORM 990, PART VI, SECTION C, LINE 19	THE SUMMARY FINANCIAL STATEMENTS ARE AVAILABLE UPON REQUEST. GOVERNING DOCUMENTS AND CONFLICT OF INTEREST POLICY ARE AVAILABLE ON OUR WEBSITE.

For Paperwork Reduction Act Notice, see the Instructions for Form 990 or 990-EZ.

Cat. No. 51056K

Schedule O (Form 990) (Rev. 1-2025)

Additional Data

Software ID:
Software Version:

- TIN:

SCHEDULE R
(Form 990)
(Rev. January 2025)

Department of the Treasury
Internal Revenue Service

Related Organizations and Unrelated Partnerships

Complete if the organization answered "Yes" on Form 990, Part IV, line 33, 34, 35b, 36, or 37.
Attach to Form 990.
Go to www.irs.gov/Form990 for instructions and the latest information.

OMB No. 1545-0047

Open to Public Inspection

Name of the organization

AMERICAN SOCIETY FOR RADIATION ONCOLOGY

Employer identification number

42-0943164

Part I

Identification of Disregarded Entities. Complete if the organization answered "Yes" on Form 990, Part IV, line 33.

(a) Name, address, and EIN (if applicable) of disregarded entity	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Total income	(e) End-of-year assets	(f) Direct controlling entity

Part II

Identification of Related Tax-Exempt Organizations. Complete if the organization answered "Yes" on Form 990, Part IV, line 34 because it had one or more related tax-exempt organizations during the tax year.

(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Exempt Code section	(e) Public charity status (if section 501(c)(3))	(f) Direct controlling entity	(g) Section 512(b)(13) controlled entity?
(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Exempt Code section	(e) Public charity status (if section 501(c)(3))	(f) Direct controlling entity	Yes	No
(1)RADIATION ONCOLOGY INSTITUTE 251 18TH STREET SOUTH 8TH FLOOR ARLINGTON,VA22202 51-0178702	TO SUPPORT AND CONDUCT RESEARCH AND EDUCATIONAL ACTIVITIES	IL	501(C)(3)	LINE 7	ASTRO	Yes
(2)ASTRO PAC 251 18TH STREET SOUTH 8TH FLOOR ARLINGTON,VA22202 06-1673960	POLITICAL ACTION COMMITTEE	VA	527		ASTRO	Yes

For Paperwork Reduction Act Notice, see the Instructions for Form 990.

Cat. No. 50135Y

Schedule R (Form 990) (Rev. 1-2025)

Page 2

Part III

Identification of Related Organizations Taxable as a Partnership. Complete if the organization answered "Yes" on Form 990, Part IV, line 34, because it had one or more related organizations treated as a partnership during the tax year.

(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Direct controlling entity	(f) Share of total income	(g) Share of end-of-year assets	(h) Disproprtionate allocations?		(i) Code V-UBI amount in box 20 of Schedule K-1 (Form 1065)	(j) General or managing partner?		(k) Percentage ownership
(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Direct controlling entity	(f) Share of total income	(g) Share of end-of-year assets	Yes	No	(i) Code V-UBI amount in box 20 of Schedule K-1 (Form 1065)	Yes	No	(k) Percentage ownership

Part IV

Identification of Related Organizations Taxable as a Corporation or Trust. Complete if the organization answered "Yes" on Form 990, Part IV, line 34 because it had one or more related organizations treated as a corporation or trust during the tax year.

(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Direct controlling entity	(e) Type of entity (C corp, S corp, or trust)	(f) Share of total income	(g) Share of end-of-year assets	(h) Percentage ownership	(i) Section 512(b)(13) controlled entity?
(a) Name, address, and EIN of related organization	(b) Primary activity	(c) Legal domicile (state or foreign country)	(d) Direct controlling entity	(e) Type of entity (C corp, S corp, or trust)	(f) Share of total income	(g) Share of end-of-year assets	(h) Percentage ownership	Yes	No

Schedule R (Form 990) (Rev. 1-2025)

Page 3

Part V

Transactions With Related Organizations. Complete if the organization answered "Yes" on Form 990, Part IV, line 34, 35b, or 36.

Note. Complete line 1 if any entity is listed in Parts II, III, or IV of this schedule.

Yes

1 During the tax year, did the orgranization engage in any of the following transactions with one or more related organizations listed in Parts II-IV?

a Receipt of (i) interest, (ii) annuities, (iii) royalties, or (iv) rent from a controlled entity .....................

b Gift, grant, or capital contribution to related organization(s) ............................

Yes

c Gift, grant, or capital contribution from related organization(s) ............................

Yes

d Loans or loan guarantees to or for related organization(s) ............................

e Loans or loan guarantees by related organization(s) ............................

f Dividends from related organization(s) ............................

g Sale of assets to related organization(s) ............................

h Purchase of assets from related organization(s) ............................

i Exchange of assets with related organization(s) ............................

j Lease of facilities, equipment, or other assets to related organization(s) .......................

k Lease of facilities, equipment, or other assets from related organization(s) ......................

l Performance of services or membership or fundraising solicitations for related organization(s) .....................

m Performance of services or membership or fundraising solicitations by related organization(s) .................

n Sharing of facilities, equipment, mailing lists, or other assets with related organization(s) ...................

Yes

o Sharing of paid employees with related organization(s) ............................

Yes

p Reimbursement paid to related organization(s) for expenses ............................

Yes

q Reimbursement paid by related organization(s) for expenses ............................

Yes

r Other transfer of cash or property to related organization(s) ............................

s Other transfer of cash or property from related organization(s) ............................

If the answer to any of the above is "Yes," see the instructions for information on who must complete this line, including covered relationships and transaction thresholds.

(a) Name of related organization	(b) Transaction type (a-s)	(c) Amount involved	(d) Method of determining amount involved
(1) RADIATION ONCOLOGY INSTITUTE	B	14,463	ACTUAL
(2) RADIATION ONCOLOGY INSTITUTE	C	10,000	ACTUAL
(3) RADIATION ONCOLOGY INSTITUTE	N	78,330	FMV
(4) RADIATION ONCOLOGY INSTITUTE	O	347,510	FMV
(5) RADIATION ONCOLOGY INSTITUTE	P	6,497	ACTUAL
(6) RADIATION ONCOLOGY INSTITUTE	Q	30,949	ACTUAL

Schedule R (Form 990) (Rev. 1-2025)

Page 4

Part VI

Unrelated Organizations Taxable as a Partnership. Complete if the organization answered "Yes" on Form 990, Part IV, line 37.

Provide the following information for each entity taxed as a partnership through which the organization conducted more than five percent of its activities (measured by total assets or gross revenue) that was not a related organization. See instructions regarding exclusion for certain investment partnerships.

(a) Name, address, and EIN of entity	(b) Primary activity	(c) Legal domicile (state or foreign country)	(e) Are all partners section 501(c)(3) organizations?		(f) Share of total income	(g) Share of end-of-year assets	(h) Disproprtionate allocations?		(i) Code V-UBI amount in box 20 of Schedule K-1 (Form 1065)	(j) General or managing partner?		(k) Percentage ownership
(a) Name, address, and EIN of entity	(b) Primary activity	(c) Legal domicile (state or foreign country)	Yes	No	(f) Share of total income	(g) Share of end-of-year assets	Yes	No	(i) Code V-UBI amount in box 20 of Schedule K-1 (Form 1065)	Yes	No	(k) Percentage ownership

Schedule R (Form 990) (Rev. 1-2025)

Page 5

Part VII

Supplemental Information

Provide additional information for responses to questions on Schedule R. See instructions.

Return Reference	Explanation

Schedule R (Form 990) (Rev. 1-2025)

Additional Data

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