LIMITATIONS OF A PENCIL BEAM APPROACH TO PHOTON DOSE CALCULATIONS IN LUNG-TISSUE

被引：122

作者：

KNOOS, T ^{[1
]}

AHNESJO, A ^{[1
]}

NILSSON, P ^{[1
]}

WEBER, L ^{[1
]}

机构：

[1] HELAX AB,S-75147 UPPSALA,SWEDEN

来源：

PHYSICS IN MEDICINE AND BIOLOGY | 1995年 / 40卷 / 09期

关键词：

D O I：

10.1088/0031-9155/40/9/002

中图分类号：

R318 [生物医学工程];

学科分类号：

0831 ;

摘要：

A common limitation in treatment planning systems for photon dose calculation is to ignore the impact on electron transport and photon scatter from patient heterogeneities. The heterogeneity correction is often based on scaling operations along beam rays as for the method according to Bathe or the more novel approach of 1D convolutions along beam paths applied in pencil-beam-based systems. The effects of the limitation have been studied in a mediastinium geometry for a wide range of beam qualities by comparing the results from a pencil-beam-based treatment planning system with the results from Monte Carlo calculations. As expected, the deviations within unit-density volumes are small while deviations in low-density volumes increase with increasing beam energy from approximately 3% for 4 MV to 14% for 18 MV x-rays as a result of increased electron disequilibrium.

引用

页码：1411 / 1420

页数：10

共 28 条

[1] A PENCIL BEAM MODEL FOR PHOTON DOSE CALCULATION [J].