Prise K M, Folkard M, Davies S, Michael B D
Cancer Research Campaign, Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, United Kingdom.
Radiat Res. 1989 Mar;117(3):489-99.
Chinese hamster V79 cells were irradiated with 1.487 keV aluminum characteristic X rays produced using a cold-cathode discharge tube. Under aerobic conditions a relative biological effectiveness (RBE) of 2.18 for cell killing in comparison to 250-kVp X rays was measured using cells grown in suspension and irradiated on membrane filters. DNA damage in the form of single-strand (ssb) and double-strand breaks (dsb) was measured using the filter elution technique. The aerobic RBEs are 1.64 for dsb induction and 0.49 for ssb induction, consistent with the view that dsb are more closely related to cell kill than ssb. A reduced oxygen enhancement ratio (OER) for cell killing was measured for Al-K X rays, but the OER for dsb induction was similar to that measured for 250-kVp X rays. A curvilinear relationship between dsb induction and dose is observed, similar to that seen for 250-kVp X rays. This agrees with the concept that ultrasoft X rays produce critical lesions similar to hard X rays but with a greater efficiency per unit dose.
用冷阴极放电管产生的1.487 keV铝特征X射线照射中国仓鼠V79细胞。在有氧条件下，使用悬浮培养并在膜滤器上照射的细胞，测得与250 kVp X射线相比细胞杀伤的相对生物效应（RBE）为2.18。使用滤膜洗脱技术测量单链（ssb）和双链断裂（dsb）形式的DNA损伤。有氧条件下dsb诱导的RBE为1.64，ssb诱导的RBE为0.49，这与dsb比ssb与细胞杀伤更密切相关的观点一致。测量了Al-K X射线对细胞杀伤的氧增强比（OER）降低，但dsb诱导的OER与250 kVp X射线测量的相似。观察到dsb诱导与剂量之间呈曲线关系，类似于250 kVp X射线的情况。这与超软X射线产生与硬X射线相似的关键损伤但单位剂量效率更高的概念一致。
