Author(s)

Masaki Sueoka^1,2*, Akira Sawada³, Hiroaki Tanabe², Yuki Okada², Sho Taniuchi², Noboru Okuuchi², Masao Tanooka¹, Masaki Kokubo⁴, Koichiro Yamakado¹

¹Department of Radiology, Hyogo College of Medicine, Nishinomiya, Japan.
²Department of Radiological Technology, Kobe City Medical Center General Hospital, Kobe, Japan.
³Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Japan.
⁴Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe, Japan.

Purpose: We performed both, dosimetric and positional accuracy verification of dynamic tumor tracking (DTT) intensity modulated radiation therapy (IMRT), with the Vero4DRT system using a moving phantom (QUASAR respiratory motion platform; QUASAR phantom) and system log files. Methods: The QUASAR phantom was placed on a treatment couch. Measurement of the point dose and dose distribution was performed for conventional IMRT, with the QUASAR phantom static and moving; for DTT IMRT, this was performed with the phantom moving for pyramid shaped, prostate, paranasal sinus, and pancreas targets. The QUASAR phantom was driven by a sinusoidal signal in the superior-inferior direction. Furthermore, predicted positional errors induced by the Vero4DRT system and mechanical positional errors of the gimbal head, were calculated using the system log files. Results and Conclusion: For DTT IMRT, the dose at the evaluation point was within 3% compared with the verification plan, and the dose distribution in the passing rates of γ was 97.9%, with the criteria of 3% dose and 3 mm distance to agreement. The position error calculated from the log files was within 2 mm, suggesting the feasibility of employing DTT IMRT with high accuracy using the Vero4DRT system.

Dynamic Tumor Tracking (DTT), Intensity Modulated Radiation Therapy (IMRT), Point Dose Verification, Dose Distribution Verification, Log File Analysis

Sueoka, M. , Sawada, A. , Tanabe, H. , Okada, Y. , Taniuchi, S. , Okuuchi, N. , Tanooka, M. , Kokubo, M. and Yamakado, K. (2019) Verification of Dosimetric and Positional Accuracy of Dynamic Tumor Tracking Intensity Modulated Radiation Therapy. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 8, 211-224. doi: 10.4236/ijmpcero.2019.84019.