Dosimetric Evaluation of 3D-Printed Polylactic Acid (PLA) Anthropomorphic Radiotherapy Head Phantom using Gafchromic EBT-XD Films, OSLD NanoDot and TLD-100

Recently, additive manufacturing or 3-dimensional (3D) printing has been utilized to create low-cost and customized radiotherapy phantoms for quality assurance and radiation dosimetry. In this study, the head phantom was fabricated by scanning a standard RANDO (R) head phantom using a Kinect (R) Xbox 360 (R) and printed using polylactic acid (PLA) with 100% infill. The 3D-printed anthropomorphic head phantoms underwent CT simulation, treatment planning, and treatment delivery, similar to the patient setup in radiotherapy with a whole brain target. Irradiation of the phantoms were delivered with a single fraction of 400 cGy using 6 MV photon beam energy. The absorbed dose was measured with three dosimeters: GafChromic EBT-XD film,TLD100, and OSLD NanoDot. Gamma analysis of EBT-XD films indicated a 30% dose difference for the irradiation's pass rate of 3D printed head phantom and RANDO (R) phantom compare to TPS dose calculation. TLD's measurement of the 3D printed phantom resulted in 99% similarity to the TPS calculation and RANDO (R) phantom TLD's results. Meanwhile, the percentage dose difference between OSLD reading of 3D printed phantom and TPS calculation was 8.1%. Therefore, this study demonstrates the feasibility of the 3D-printed head RP as an alternative phantom to RANDO (R) head RP. Further improvement in the phantom design details might enhance the dosimetry outcome and accuracy.