Purpose: To create a treatment plan for the Radixact treatment machine to be delivered to the IROC Lung Phantom (with motion table) that meets the IROC Lung Phantom minimum dosimetric criteria. Meeting the IROC Lung Phantom dosimetric criteria helps credential the Radixact machine to participate in the Veterans Administration’s VALOR protocol.
Methods: IROC Lung Phantom was placed on the supplied motion table, and the phantom and motion table were scanned on a Canon Celesteion PET/CT simulator. Phantom/motion table images were transferred from PET/CT to RayStation for contouring. Phantom/motion table contours were created per IROC phantom instructions and then transferred to Accuray Precision Treatment Planning System (TPS). Treatment plans to deliver 600 cGy in 1 fraction were created utilizing TomoHelical (IMRT & 3DCRT), Static IMRT, TomoDirect 3DCRT, and Forward Planning methods on the IROC Lung Phantom image set. Dose Volume Histograms (DVH) for each type of treatment plan created were evaluated against each other. The planning method that met dose constraints and PTV coverage the best was chosen for delivering a treatment to the IROC Lung Phantom. QA of the chosen plan was performed utilizing the Sun Nuclear ArcCHECK device. If the gamma % passing result was > 95% for 3%/2mm DTA, the QA was considered acceptable, and the treatment plan was approved. The approved treatment plan was then delivered to the IROC Lung Phantom on the included active motion table. Phantom and motion table then returned to IROC.
Results: The TomoDirect 3DCRT 2.5 cm FW plan had best PTV coverage, highest minimum PTV dose, and shortest treatment time. Lung phantom irradiation passed IROC criteria.
Conclusion: An acceptable plan was created that passed the IROC Lung Phantom benchmark test which allowed credentialing approval for our institution to participate in the VALOR protocol trial.