کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5499258 | 1533487 | 2017 | 4 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
An MCNPX2.7.0 study of Bragg peak degradation owing to density heterogeneity patterns for a CGMH therapeutic proton beam
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موضوعات مرتبط
مهندسی و علوم پایه
فیزیک و نجوم
تشعشع
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چکیده انگلیسی
The purpose of this study was to investigate the density heterogeneity pattern as a factor affecting Bragg peak degradation, including shifts in Bragg peak depth (ZBP), distal range (R80 and R20), and distal fall-off (R80-R20) using Monte Carlo N-Particles, eXtension (MCNPX). Density heterogeneities of different patterns with increasing complexity were placed downstream of commissioned proton beams at the Proton and Radiation Therapy Centre of Chang Gung Memorial Hospital, including one 150Â MeV wobbling broad beam (10Ã10Â cm2) and one 150Â MeV proton pencil beam (FWHM of cross-plane=2.449Â cm, FWHM of in-plane=2.256Â cm). MCNPX 2.7.0 was used to model the transport and interactions of protons and secondary particles in density heterogeneity patterns and water using its repeated structure geometry. Different heterogeneity patterns were inserted into a 21Ã21Ã20Â cm3 phantom. Mesh tally was used to track the dose distribution when the proton beam passed through the different density heterogeneity patterns. The results show that different heterogeneity patterns do cause different Bragg peak degradations owing to multiple Coulomb scattering (MCS) occurring in the density heterogeneities. A trend of increasing R20 and R80-R20 with increasing geometry complexity was observed. This means that Bragg peak degradation is mainly caused by the changes to the proton spectrum owing to MCS in the density heterogeneities. In contrast, R80 did not change considerably with different heterogeneity patterns, which indicated that the energy spectrum has only minimum effects on R80. Bragg peak degradation can occur both for a broad proton beam and a pencil beam, but is less significant for the broad beam.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Radiation Physics and Chemistry - Volume 137, August 2017, Pages 121-124
Journal: Radiation Physics and Chemistry - Volume 137, August 2017, Pages 121-124
نویسندگان
Tsi-Chian Chao, Yi-Chun Tsai, Shih-Kuan Chen, Shu-Wei Wu, Chuan-Jong Tung, Ji-Hong Hong, Chun-Chieh Wang, Chung-Chi Lee,