F34-Ⅰ型深部X射线治疗机固定照射野间照射量率的比值确定

On the Ratio of Exposure Rates under Fired Irradiation Fields for the F34-Ⅰ In-depth X-ray Therapeutic Machine

测量了１２部Ｆ３４－Ⅰ型深部 Ｘ射线治疗机的照射量率，确定了固定照射野在 １５ × １０、１０ × ８、８ × ６、６ × ４单位ｃｍ×ｃｍ）情况下的照射量率比值：在空气介质中，源皮距为３０ｃｍ时，分别为１．０１５、１．０００、０．９７６、０．９５１以及源皮距为４０ｃｍ时，分别为１．０２６、１．０００、０．９７２、０．９４１；在水模体介质中，源皮距４０ｃｍ时，分别为１．１３６、１．０００、０．８７３、０．７３４。利用这些比值，可以快速准确计算出实际照射量率，为治疗恶性肿瘤提供准确可靠的剂量率值。

The exposure rates of twelve F34-I in-depth X-ray machines and their ratios of exposure rates were measured under fixed irradiation fields 15 x 10, 10 x 8,8 x 6,and 6 x 4(cm x cm). For a source-skin distance of 30 cm in air, the ration determined are equal to 1.015, 1.000,0.976, and 0.951. For a someeskin distance of 4O cm in air, the ratios obtained are 1.026, 1.000,0.972, and 0.941. For a source-skin distance of 40 cm in water,the ratios equal to 1.136, 1.000,0.873, and 0.734.With the aid of these ratios, the actual exposure rates can be estimated accurately and quickly, which are essential for the exact and reliable supply of dosage in malignant tumor radiotherapy.