SU‐E‐T‐180: The Radiological Physics Center's Anthropomorphic Quality Assurance Phantom Program

Purpose: To describe the phantoms, program logistics and current results for the Radiological Physics Center's (RPC) anthropomorphic QA phantom program for credentialing institutions for participation in NCI‐sponsored advanced technology clinical trials. Methods: The RPC has developed an extensive phantom credentialing program consisting of four different phantoms designs: HN, pelvis, lung and spine. These QA phantoms are water‐filled plastic shells with imageable targets, avoidance structures, and heterogeneities that contain TLD and radiochromic film dosimeters. Institutions wishing to be credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, the phantom is positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution's electronically submitted treatment plan dosimetry data. Results: The RPC currently has an inventory of 31 HN, 10 pelvis, 9 lung, and 8 spine phantoms that are mailed to institutions nationally and internationally. In 2011, 444 of these phantoms were mailed out for credentialing. Once the phantom is sent, it takes the institution an average of 26 days to return it to the RPC. On average the dosimeters are analyzed within 17 days and the report is sent 21 days after receipt of the phantom data. In 2011 the percent of phantoms meeting the acceptance criteria increased by 12, 13 and 6 percentage points for the HN, spine and lung phantoms, respectively. It fell by 5 percentage points for the pelvis phantom. Conclusions: The RPC's QA phantom program has been an effective and responsive QA tool for assessing the use of advanced technologies in NCI sponsored clinical trials. The RPC has been efficient in its mailing of phantoms, and analyzing and reporting results. Work supported by PHS grant CA10953 and CA081647 (NCI, DHHS).