A Study on Beam Flattening Based on Compact Double Scatterer Applicable to Rotational Beam Irradiation System in the Proton Therapy Facility at CYRIC, Tohoku University

Abstract

Proton therapy facility at Cyclotron and Radioisotope Center (CYRIC) in Tohoku University includes a horizontal beam line, currently used for research studies, and also a rotational beam irradiation system which is under construction. This system will be able to change the beam irradiation angle from 0 to 180 degree around the target and the beam delivery on the target volume is done passively using scatterers and ridge filters. In this rotational beam irradiation system due to the limitation on the available space between the beam exit window to the target location, a compact compensated contoured double scattering system was proposed to create the lateral homogeneous dose profile. This work represents the evaluation of this compact double scatterer and its application to the rotational beam irradiation system. The experiments were performed using the horizontal beam line by considering to the status of the rotational beam irradiation system in the target room 5 at CYRIC. The experimental results represent the lateral dose distribution with a proper treatment region which is in a good agreement with simulated data.

Investigation the Performance Accuracy of Contoured Dual Ring Double Scatterer System for Flat Beam Generation at Proton Therapy

“…It should be noted that the Bragg peak curve obtained by simulation method has close correlation with same curve obtained experimen-tally using Imaging Plate at our last research work [22].…”

“…It should be noted that the produced treatment region has reasonable uniformity according to the definition of uniformity degree formula [21][22]. Moreover, the semi-penumbra of flat beam profile representing the protons with non-uniform 3D spatial distribution is stopped with proper collimators and only the protons with uniform spatial distributions are allowed to pass and penetrate to the patient body and irradiate target volume.…”

“…The upper part shown is the Figure 2 was assessed formerly at our last study [22]. In this study, we investigate lower strategy using FLUKA code and the final results of its perfor-Figure 1: A schematic layout of single scatterer with wobbler system.…”

“…To do these aims, a validated Monte Carlo FLUKA code is utilized to simulate the performance of proposed double scattering system [25][26][27][28][29][30]. It should be noted that the simulation process is very close to real experimental condition at proton beam room in CYRIC center at Tohoku University in Japan to mimic real condition [20][21][22] and final results represent that the scattering system is robust to generate flat region in lateral direction.…”

“…Several research works have been done on the performance of various instruments for providing lateral flattening regions, ranging from their designs to simulations and fabrications. At our last work, a comprehensive assessment was done on the design and fabricating a contoured compact dual scatterers applicable at Rotating Gantry system in Cyclotron and Radioisotope Center (CYRIC) at Tohoku University in Japan [20][21][22]. In this work, we are interested to design and simulate another version of scattering system entitled dual ring double scatterer as an alternative to be implemented for proton beam line.…”