放疗中挡铅托盘对皮肤剂量的影响。

Effect of block trays on skin dose in radiotherapy.

作者信息

Butson M J, Mathur J N, Metcalfe P E

机构信息

Illawarra Cancer Care Centre, Department of Radiotherapy, Wollongong NSW, Australia.

出版信息

Australas Phys Eng Sci Med. 1996 Dec;19(4):248-51.

PMID:9060211

Abstract

Percentage dose at the surface and at 1 mm depth for megavoltage photon beams are increased through the influence of block trays. This represents a decrease in skin sparing properties for both the epidermal and dermal layers. The increase in percentage dose varies with type and thickness of block tray material. At 6MVp, 20cm x 20cm field size, the percentage surface dose is 26%, 26.5%, 33% and 35% for open, steel honeycomb tray, 6mm perspex and 10 mm perspex block trays respectively. At 1 mm depth these values are 52%, 52.5%, 61%, 60% respectively. A similar effect is seen at higher energies. Results show that care should be taken when selecting an appropriate block tray if skin sparing is of importance.

摘要

通过挡块托盘的影响，兆伏级光子束在体表和1毫米深度处的剂量百分比会增加。这意味着表皮层和真皮层的皮肤保护特性降低。剂量百分比的增加因挡块托盘材料的类型和厚度而异。在6MVp、20cm×20cm射野尺寸下，开放野、钢蜂窝托盘、6mm有机玻璃和10mm有机玻璃挡块托盘的体表剂量百分比分别为26%、26.5%、33%和35%。在1毫米深度处，这些值分别为52%、52.5%、61%、60%。在更高能量下也观察到类似的效果。结果表明，如果皮肤保护很重要，那么在选择合适的挡块托盘时应谨慎。