摘要
This study was carried out to look for the substitute products of lead cerrobend block and determine whether the products can give more radiation dose to the tumor in the skin and superficial tumors in radiotherapy treatment. Five kinds of PbO/ Er203/Epoxy（E-51） samples used as the cerrobend block in the electron beam radiotherapy treatment were prepared success- fully by a solidified forming approach. The central axis depth dose and off-axis dose profiles in the water phantom were calcu- lated using BEAMnrc/DOSEXYZnrc user codes. The results revealed that there were more energy deposition events induced by low energy electron beams in the surface of the water phantom. These electron beams were attributed to Compton scattering and photoemission between photons and erbium, plumbum elements. The maximum dose （Dm） and the depth at the maximum dose （Rm） were linearly dependent on the mass fraction of erbium and plumbum element in the sample. The max dose and its depth varied depending on the combined actions of new electrons and transmission electrons.
基金
supported by the Natural Science Foundation of Jiangsu province (Grant No. BK2008400)
the China Postdoctoral Science Foundation (Grant No. 20100471338)
National Natural Science Foundation of China (81071256)
NUAA Research Funding (Grant No. NS2010152)
