|
KMID : 1151820210150060771
|
|
Journal of the Korean Society of Radiology
2021 Volume.15 No. 6 p.771 ~ p.779
|
|
|
Depth Dose Distribution of Proton Beams by Variation of Tumor Density using Geant4
|
|
Kim You-Me
Chon Kwon-Su
|
|
|
Abstract
|
|
|
|
t is necessary to overlap several peaks to form spread out Bragg peak (SOBP) in order to cover the tumor volume because a mono-energetic proton beam forms a narrow Bragg peak. The tumor density has been considered as a brain tissue and then the absorbed dose of the tumor is calculated using Monte Carlo simulations. However, densities of tumors were not a constant. In this study, the SOBP of proton beams was calculated according to changing density of tumors by using Geant4. Tumors were selected as 10 mm and 20 mm width which were the treatment range in the brain phantom. The energies and relative weights of the proton beams were calculated using mathematical formula to form the SOBP suitable for the location and size of the tumor. As the density of the tumor was increased, the 95% modulation range and the practical range were decreased, and average absorbed dose in the 95% modulation range was increased. The change of the tumor density affects the dose distribution of the proton beams, which results in short SOBP within the tumor volume. The consideration of the tumor density affects the determination of the range, so that the margin of the treatment volume can be minimized, and the advantages of proton therapy can be maximized.
|
|
|
KEYWORD
|
|
|
Proton Therapy , Bragg Peak , Monte Carlo Simulation , Geant4
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|