Development of O-ring Type Radiation Treatment Equipment Shielding Evaluation and Management Program

Abstract The objective of this study is to evaluate the effectiveness of O-ring type linear accelerator shielding using a developed program (O-ring Type Radiation therapy Equipment Shielding Evaluation, ORSE) that automatically evaluates Digital Imaging and Communications in Medicine Radiation Therapy (DICOM RT) plan files and applies them to determine the adequacy of the shielding. The shielding evaluation was conducted for a total of four treatment rooms including Magnetic Resonance Linear Accelerator (MR-LINAC), Halcyon, Tomotherapy. The analysis was performed using the program that analyzed DICOM RT plan files of patients who received treatment for five days. The program obtained the IMRT factor, which considered the Monitor Unit (MU), and the use factor, which considered the gantry angle. Based on the National Council on Radiation Protection & Measurements (NCRP)-151 report, shielding calculations were performed to determine the transmitted dose for each location behind the barrier, and the maximum number of treatable patients and the shield wall thickness were calculated based on patient data. To compare the results with the program, doses were measured over five days using a glass dosimeter for photon detection. The IMRT factors and Use factors obtained from patient data showed differences of up to 65.0% and 33.8%, respectively, compared to NCRP-151. Shielding evaluation conducted in each treatment room showed that the transmitted dose at every location was below 1% of the dose limit. The program results and detector results showed a maximum error of 0.003 mSv/week in transmitted dose. The ORSE program allows for the shielding evaluation results to the clinical environment of each institution based on patient data for the desired analysis period through straightforward manipulation.