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        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 2</FormAndLineReferenceDesc>
        <ExplanationTxt>TWO OF THE ORGANIZATION'S VOTING MEMBERS WHO SERVED DURING THE FISCAL YEAR ARE EMPLOYED BY YALE NEW HAVEN HEALTH SERVICES CORPORATION AND TWO OF THE ORGANIZATION'S VOTING MEMBERS ARE EMPLOYED BY HARTFORD HEALTHCARE CORPORATION.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 3</FormAndLineReferenceDesc>
        <ExplanationTxt>THE ORGANIZATION DELEGATED CONTROL OVER MANAGEMENT DUTIES TO PARTNERS IN HEALTHCARE TECHNOLOGY, LLC</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 6</FormAndLineReferenceDesc>
        <ExplanationTxt>THE TWO MEMBERS ARE YALE NEW HAVEN HEALTH SERVICES CORPORATION AND HARTFORD HEALTHCARE CORPORATION.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 7A</FormAndLineReferenceDesc>
        <ExplanationTxt>YALE NEW HAVEN HEALTH SERVICES CORPORATION AND HARTFORD HEALTHCARE CORPORATION SHALL HAVE THE RIGHT TO ELECT THE FILING ORGANIZATION'S MANAGEMENT COMMITTEE MEMBERS IN ACCORDANCE WITH THE OPERATING AGREEMENT.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION A, LINE 7B</FormAndLineReferenceDesc>
        <ExplanationTxt>THE MANAGEMENT COMMITTEE MEMBERS SHALL CONSULT REGULARLY WITH APPROPRIATE OFFICIALS OF YALE NEW HAVEN HEALTH SERVICES CORPORATION AND HARTFORD HEALTHCARE CORPORATION TO INSURE THAT ALL OF THE ACTIVITIES OF THIS CORPORATION ARE CONSISTENT WITH THE CHARTER, BYLAWS, RULES, REGULATIONS AND POLICIES OF YALE NEW HAVEN HEALTH SERVICES CORPORATION AND HARTFORD HEALTHCARE CORPORATION.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINE 11B</FormAndLineReferenceDesc>
        <ExplanationTxt>THE FORM 990 TAX RETURN AND ATTACHED SCHEDULES WERE PREPARED BY EMPLOYEES OF YALE NEW HAVEN HEALTH SERVICES CORPORATION'S TAX DEPARTMENT. THE RETURN IS INITIALLY REVIEWED BY THE EXECUTIVE DIRECTOR OF CORPORATE FINANCE. SUBSEQUENTLY IT IS SENT TO KPMG LLP FOR THEIR INITIAL REVIEW. AFTER ALL COMMENTS FROM THE ABOVE GROUPS ARE CLEARED, THE RETURN IS THEN REVIEWED BY HARTFORD HEALTHCARE CORPORATION'S TAX DEPARTMENT. UPON THEIR REVIEW, A FINAL VERSION OF THE RETURN IS SENT BACK TO KPMG LLP FOR FINAL REVIEW. PRIOR TO FILING THE ORGANIZATION MADE AVAILABLE A COMPLETE COPY OF THE RETURN TO THE MANAGEMENT COMMITTEE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINE 12</FormAndLineReferenceDesc>
        <ExplanationTxt>CONNECTICUT PROTON THERAPY CENTER, LLC'S, EIN 87-1371777, (THE "ENTITY"), WHILE THE ENTITY DID NOT ADOPT A WRITTEN CONFLICT OF INTEREST POLICY, WHISTLEBLOWER POLICY OR DOCUMENT RETENTION AND DESCTRUCTON POLICY IN THE TAX PERIOD ENDING 9/30/2024, THE ENTITY HAS SINCE ADOPTED THESE POLICIES ON 9/19/25 WITHIN THE TAX PERIOD ENDING 9/30/2025.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION C, LINE 19</FormAndLineReferenceDesc>
        <ExplanationTxt>COPIES OF ALL DOCUMENTS ARE AVAILABLE TO THE PUBLIC UPON REQUEST.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART IX, LINE 11G</FormAndLineReferenceDesc>
        <ExplanationTxt>PROFESSIONAL FEES: PROGRAM SERVICE EXPENSES 1,002,341. MANAGEMENT AND GENERAL EXPENSES 0. FUNDRAISING EXPENSES 0. TOTAL EXPENSES 1,002,341.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART X</FormAndLineReferenceDesc>
        <ExplanationTxt>CONNECTICUT PROTON THERAPY CENTER, LLC'S, EIN 87-1371777, (THE "ENTITY"). THE ENTITY CONVERTED FROM A PARTNERSHIP TO A TAX-EXEMPT ENTITY EFFECTIVE 9/4/2024. THE BALANCES SHOWN ON THE BEGINNING BALANCE SHEET FOR THIS FILING REMAINED WITHIN THE ENTITY AS IT TRANSITIONED FROM A PARTNERSHIP TO A TAX-EXEMPT ENTITY.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART XI, LINE 9:</FormAndLineReferenceDesc>
        <ExplanationTxt>PRIOR PERIOD ADJUSTMENT -53,162.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART XI, LINE 9</FormAndLineReferenceDesc>
        <ExplanationTxt>CONNECTICUT PROTON THERAPY CENTER, LLC'S, EIN 87-1371777, (THE "ENTITY"), IRS FORM 990 THE DECREASE IN NET ASSET RELATES TO A PRIOR PERIOD ADJUSTMENT DECREASING FIXED ASSETS AND COST OF ISSUANCE WHEN THE ENTITY WAS CLASSIFIED AS A PARTNERSHIP.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>