Translation and rotational target motion effect in NSCLC case with 3D-CRT, IMRT, and VMAT techniques using in-house dynamic thorax phantom

This study aimed to make in-house dynamic thorax phantom that simulate translational and rotational direction mimicking NSCLC target movement. In addition,this study also investigate dosimetric effect of target movement for several translational amplitude. This work used in-house dynamic thorax phantom based on CIRS Dynamic Thorax Phantom model 008A. This phantom simulated translation in superior-inferior direction, rotational in the anterior-posterior and left-right lateral plane to mimic human respiratory motion. It was designed and controlled by linear actuator motor, servo motor, Adafruit motor shield L293D and Arduino UNO R3. It was implemented to evaluate point dose of 3D-CRT, IMRT, VMAT technique and for 5 mm; 10 mm; 15 mm translational motion amplitude 90° rotational target motion amplitude. The GafChromic EBT 3 film was used as a dosimeter for point dose measurement. This in-house dynamic thorax phantom can mimicking NSCLC target movement for translational amplitude 5 ± 1 mm; 10 ± 1 mm; 15 ± 1 mm and rotational amplitude 90° ± 3°. The average dose deviation of target dose (centre and peripheral) of TPS dose planning and target motion measurement on 3DCRT with 5 mm, 10 mm and 15 mm were 3.2%, 3.1%, and 1.8% respectively, and dose deviation on IMRT were 3.9%, 2.5%, and 2.8%, while dose deviation on VMAT treatment were 4.2%, 4.6%, and 6.1% respectively. The preliminary result supported the previous work by Mukhlisin. Furthermore, rotational movement of phantom contributed in average of 1.5% compare to translational movement only.