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The 50th Anniversary of the Radiological Physics Center/IROC Houston QA Center Activities and Findings

D Followill*, J Lowenstein , P Taylor , A Molineu , P Alvarez , G Ibbott , W Hanson , S Kry , MD Anderson Cancer Ctr., Houston, TX


(Sunday, 7/29/2018) 1:00 PM - 1:55 PM

Room: Davidson Ballroom A

Purpose: The RPC/IROC-Houston QA Center was established in 1968 and has, for the past 50 years, contributed to the development, conduct, and QA of NCI funded multi-institutional cooperative group clinical trials and their participating institutions, in North America and 52 other countries.

Methods: The implemented QA program, which is the largest in the world, is designed to audit the radiation dose calculation/delivery chain from the NIST traceable reference beam calibration, to the dosimetry parameters used to calculate tumor doses, to the delivery of the treatment. The QA program includes: 1) remote TLD/OSLD audit of machine output, 2) on-site dosimetry review visits, 3) credentialing for advanced technologies, and 4) review of patient treatment records. Findings are presented and published to the radiation oncology community.

Results: The number of institutions monitored has increased from around 1300 in the late 90s, to 2200 in 2018. There were over 4000 therapy machines and 24,600 therapy beams monitored at institutions by 2018. A total of 301,719 beam output checks have been performed since 1968. Within the 17,000 photon, electron and proton beam outputs monitored with annually TLD/OSLD since 2000, 6-22% of the institutions have one or more beams outside the 5% criterion. Dosimetry site visits to institutions continue to result in 2-4 recommendations affecting key dosimetry parameters. One in four patient treatment records reviewed require their reported dose data to be corrected by >5%. End-to-end phantom audits exceed 700 annually with an average failure rate of 10-15%. Twenty-four of 28 clinically active proton centers are approved to participate clinical trials. Since 1972, 261 peer reviewed articles have been published.

Conclusion: The RPC/IROC-Houston efforts and findings over the past 50 years suggest that errors continue to manifest in radiotherapy, and without its independent QA program, many of these errors would go undetected.

Funding Support, Disclosures, and Conflict of Interest: 5U24CA180803


Quality Assurance


TH- External beam- photons: Quality Assurance - Linear accelerator

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