Raaphorst GP, Yang DP, Ng CE
Ottawa Regional Cancer Centre, 501 Smyth Road, Ottawa, Canada
J Therm Biol. 2000 Aug 1;25(4):305-311. doi: 10.1016/s0306-4565(99)00103-5.
Long duration mild hyperthermia (LDMH) has been shown to be an effective radiosensitizer when combined with low dose rate irradiation and pulsed low dose rate irradiation. These protocols are being investigated to determine if these effects can be related to DNA double strand breakage (dsb). In our studies we used human melanoma (SK mel-3) and fibroblasts (AG1522). A low dose rate was given at 0.88 cGy/min while pulsed doses were given at 150 cGy/min. Our results showed that the degree of thermal radiosensitization (TER) increased as the average dose rate decreased. This was seen for both the survival endpoints and the degree of DNA strand breaks. There was a very good correlation between the TER and the degree of DNA strand breaks.In conclusion our data show that LDMH is an effective radiosensitizer for both LDR and PSLDR and this may also be an effective clinical protocol. The quantity of DNA dsb's appears to be related to TER and may be predictive of the degree of radiosensitization.
长期轻度热疗（LDMH）已被证明与低剂量率照射和脉冲低剂量率照射联合使用时是一种有效的放射增敏剂。正在对这些方案进行研究，以确定这些效应是否与DNA双链断裂（dsb）有关。在我们的研究中，我们使用了人黑色素瘤（SK mel-3）和成纤维细胞（AG1522）。低剂量率以0.88 cGy/分钟给予，而脉冲剂量以150 cGy/分钟给予。我们的结果表明，随着平均剂量率降低，热放射增敏程度（TER）增加。这在生存终点和DNA链断裂程度方面均有体现。TER与DNA链断裂程度之间存在非常好的相关性。总之，我们的数据表明，LDMH对低剂量率照射（LDR）和脉冲低剂量率照射（PSLDR）都是一种有效的放射增敏剂，这也可能是一种有效的临床方案。DNA双链断裂的数量似乎与TER相关，并且可能预测放射增敏程度。
