The Feasibility Study for the New IMRT Technique of Expansion Radiation Field Using the Vero4DRT Gimbal Mechanism
S Kabuki1*, M Yoshida2, T Yamakawa2, E Kunieda1, (1) Tokai University, Isehara, Kanagawa,(2) Mitsubishi Heavy Industries, LTD, Hiroshima City, Hiroshima,SU-E-T-388 Sunday 3:00PM - 6:00PM Room: Exhibit Hall
We have developed and evaluate a field size-expansion IMRT using the gimbal mechanism for the vero4DRT, which have been developed by Mitsubishi Heavy Industries LTD/Brainlab is one of the linacs for the next generation.
A beam head of vero4DRT can move along the pan and tilt direction independently using the gimbal mechanism. In this study, we individually investigated the new technique of the gimbal usage for expanding a field size by an intensity modulated radiation therapy (IMRT), which was first reported by Kyoto University. Our basic method is to expand the effective field size created by two main fields with two irradiation directions using gimbal mechanism. A dose distribution for the case with multi gantry and two gimbal angles were calculated by a Monte Carlo simulation (Geant4 9.4pathch03) for the conventional IMRT and the field size-expansion IMRT. These results were compered each other.. The conditions were as follows; using the cylindrical shaped phantom with two targets and the beams from 7 directions.
We have developed a program for the simulation and calculated the dose distribution of IMRT. The program succeeded to expand the field size 15 cm x 15 cm to 15 cm x 23 cm with IMRT calculation. We were able to demonstrate the potential of expanding IMRT radiation field using the optimization program. It allows us to evaluate the possibility of the improved dose distribution using the gimbal mechanism for IMRT.
We have proposed a new method of irradiation using a gimbal mechanism of vero4DRT. By using this method, the possibility of a new radiotherapy can be realized. Moreover, not only due to the gimbal mechanism, vero4DRT has a possibility of realizing a new and unparalleled treatment all independent mechanical freedom, depending on the development of the controlling software and the treatment planning algorithm.
Funding Support, Disclosures, and Conflict of Interest: This work was supported by Mitsubishi Heavy Industries, LTD.