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        <FormAndLineReferenceDesc>PART V, LINE 4:</FormAndLineReferenceDesc>
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      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>PART X, LINE 2:</FormAndLineReferenceDesc>
        <ExplanationTxt>ROI PERFORMED AN EVALUATION OF UNCERTAIN TAX POSITIONS FOR THE YEAR ENDED DECEMBER 31, 2015, AND DETERMINED THAT THERE ARE NO MATTERS THAT WOULD REQUIRE RECOGNITION IN THE FINANCIAL STATEMENTS OR THAT MAY HAVE ANY EFFECT ON ITS TAX-EXEMPT STATUS.</ExplanationTxt>
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      <RecipientTable>
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        <FormAndLineReferenceDesc>PART I, LINE 2:</FormAndLineReferenceDesc>
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        <FormAndLineReferenceDesc>PART I, LINE 3</FormAndLineReferenceDesc>
        <ExplanationTxt>ROI DOES NOT DIRECTLY HIRE OR COMPENSATE EMPLOYEES. ALL EMPLOYEES ARE EMPLOYEES OF THE AMERICAN SOCIETY FOR RADIATION ONCOLOGY (ASTRO), A RELATED ORGANIZATION EXEMPT UNDER SECTION 501(C)(6). AN INDEPENDENT CONSULTANT PERFORMED MARKET SURVEY TO DEVELOP SALARY STRUCTURE AND RANGES. ASTRO'S PRACTICE IS TO COMPLETE A MARKET SURVEY EVERY THREE YEARS; THIS WAS LAST COMPLETED FOR THE EX-OFFICIO, EXECUTIVE DIRECTOR IN 2012. THE EX-OFFICIO, EXECUTIVE DIRECTOR'S COMPENSATION IS DETERMINED BY A SUBCOMMITTEE OF THE BOARD USING COMPARABLE SALARIES OF SIMILAR EXECUTIVE DIRECTOR POSITIONS OF NONPROFIT MEDICAL ORGANIZATIONS. THIS REVIEW WAS DISCUSSED WITH THE BOARD OF DIRECTORS AND THE FINAL DETERMINATION WAS MADE BY THE EXECUTIVE COMMITTEE.</ExplanationTxt>
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      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART III, LINE 3</FormAndLineReferenceDesc>
        <ExplanationTxt>AS OF JUNE 2014, ROI IS NO LONGER INVOLVED IN THE NATIONAL RADIATION ONCOLOGY REGISTRY PROGRAM.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 3</FormAndLineReferenceDesc>
        <ExplanationTxt>ALL MANAGEMENT FUNCTIONS OF ROI ARE CONTROLLED BY THE AMERICAN SOCIETY FOR RADIATION ONCOLOGY (ASTRO), A RELATED ORGANIZATION EXEMPT UNDER SECTION 501(C)(6).</ExplanationTxt>
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      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 4</FormAndLineReferenceDesc>
        <ExplanationTxt>DURING THE YEAR ENDED DECEMBER 31, 2015 ROI MADE CHANGES TO OUR BYLAWS WHICH AFFECTED THE COMPOSITION OF OUR BOARD OF TRUSTEES.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINE 11</FormAndLineReferenceDesc>
        <ExplanationTxt>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 CFO, CEO, AND TREASURER OF ASTRO FOR THEIR REVIEW AND APPROVAL. THE REVISED DRAFT IS THEN PROVIDED TO THE FULL BOARD OF DIRECTORS PRIOR TO FILING WITH THE INTERNAL REVENUE SERVICE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINE 12C</FormAndLineReferenceDesc>
        <ExplanationTxt>ROI'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 THESE INDIVIDUALS.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION C, LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>THE ANNUAL REPORT WITH SUMMARY FINANCIAL STATEMENTS IS DISTRIBUTED TO MEMBERS AND IS AVAILABLE FOR MEMBERS ON OUR WEBSITE. GOVERNING DOCUMENTS AND CONFLICT OF INTEREST POLICY ARE AVAILABLE ON OUR WEBSITE.</ExplanationTxt>
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      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART IX, LINE 11G</FormAndLineReferenceDesc>
        <ExplanationTxt>PROFESSIONAL FEES: PROGRAM SERVICE EXPENSES 18,952. MANAGEMENT AND GENERAL EXPENSES 67,814. FUNDRAISING EXPENSES 1,464. TOTAL EXPENSES 88,230.</ExplanationTxt>
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