Portal dose image (PDI) prediction for dosimetric treatment verification in radiotherapy. I. An algorithm for open beams

被引：82

作者：

Pasma, KL ^{[1
]}

Heijmen, BJM ^{[1
]}

Kroonwijk, M ^{[1
]}

Visser, AG ^{[1
]}

机构：

[1] Univ Rotterdam Hosp, Dr Daniel Den Hoed Canc Ctr, Dept Clin Phys, NL-3075 EA Rotterdam, Netherlands

来源：

MEDICAL PHYSICS | 1998年 / 25卷 / 06期

关键词：

treatment verification; quality assurance; transmission dosimetry; portal imaging; portal dose image (PDI);

D O I：

10.1118/1.598293

中图分类号：

R8 [特种医学]; R445 [影像诊断学];

学科分类号：

1002 ; 100207 ; 1009 ;

摘要：

A method is presented for calculation of transmission functions for high energy photon beams through patients. These functions are being used in our clinic for prediction of portal dose images (PDIs) which are compared with PDIs measured with an electronic portal imaging device (EPID). The calculations are based on the planning CT-scan of the patient and on the irradiation geometry as determined in the treatment planning process. For each beam quality, the required input data for the algorithm for transmission prediction are derived from a limited number of measured beam data. The method has been tested for a PDI-plane at 160 cm from the focus, in agreement with the fixed focus-to-detector distance of our fluoroscopic EPIDs. For 6, 23 and 25 MV photon beams good agreement (similar to 1%) has been found between calculated and measured transmissions through anthropomorphic phantoms. (C) 1998 American Association of Physicists in Medicine. [S0094-2405(98)02006-9].

引用

页码：830 / 840

页数：11

共 35 条

[1] High-precision prostate cancer irradiation by clinical application of an offline patient setup verification procedure, using portal imaging [J].