Multifractionated hyperthermia treatment of malignant and normal tissue in vivo.
Multifractionated hyperthermia treatment of malignant and normal tissue in vivo.
复制标题
体内恶性和正常组织的多次分次热疗治疗。
作者：
J. Overgaard;H. Suit;A. Walker
研究了甲基胆蒽诱导的纤维肉瘤(FSAL)及其周围正常组织热损伤的恢复情况。移植到C3H小鼠足部的肿瘤在水浴中进行治疗，每隔2小时、6小时或24小时和42.5-44.5°分别给予两个等量的热。结果被分析了120天，作为50%的肿瘤控制剂量，以及在一半的治疗动物中达到特定水平的正常组织损伤所需的剂量。
结果显示，间隔长达24小时的分割治疗在肿瘤和正常组织中恢复缓慢且几乎平行。治疗间隔6小时，肿瘤控制量和反应剂量的50%值与单次热暴露的剂量值无显著差异。事实上，对于2小时的间隔，50%的肿瘤控制剂量和50%的反应剂量值低于单一治疗。这可能是由于第一次热暴露引起的短期生理变化。对于24小时的分割时间间隔，注意到中等程度的修复，恢复率在1.27至1.56之间。由于在肿瘤和正常组织中发现了平行的恢复，所以使用这里研究的两个部分方案在治疗比率上没有明显的变化。分级热损伤的时间-温度关系与单一处理后的时间-温度关系没有什么不同。
在43.5°的温度下，研究了多分步加热的效果。每天的治疗导致了显著的恢复，肿瘤的恢复率和两种不同程度的正常组织损伤，在五个部分的加热中为2.6至2.9，在十个部分的计划中加热为4.2至6.3。尽管增加组分的数量往往会导致正常组织损伤的恢复率高于肿瘤组织损伤的恢复率，但这一发现在统计学上并不显著。
Recovery from thermal damage was studied in a methylcholanthrene-induced fibrosarcoma (FSal) and the surrounding normal tissue. Tumors isotransplanted into the feet of C3H mice were treated in a water bath with two equal fractions of heat given at 2-, 6-, or 24-hr intervals and at 42.5–44.5°. The results were analyzed at 120 days as the 50% tumor control dose and as the dose required to achieve a specified level of normal tissue damage in one-half of the treated animals.
The results show a slow and nearly parallel recovery in tumor and normal tissue for split treatments with intervals up to 24 hr. For an intertreatment interval of 6 hr, 50% tumor control dose and 50% response dose values were not different from those for single heat exposure. In fact, for a 2-hr interval, the 50% tumor control dose and 50% response dose values were lower than those for single treatments. This is probably due to short-term physiological changes induced by the first heat exposure. For split time intervals of 24 hr, a moderate degree of repair was noted with recovery ratios between 1.27 and 1.56. Owing to parallel recovery found in tumors and normal tissue, no significant variations in the therapeutic ratio could be obtained by use of the two fraction schedules studied here. The time-temperature relationship for fractionated thermal damage was not different from that seen after a single treatment.
The effect of multifractionated hyperthermia was studied at a temperature of 43.5°. Daily treatments resulted in a pronounced recovery, with recovery ratios for tumor and two different levels of normal tissue damage at 2.6 to 2.9 for heating in five fractions and 4.2 to 6.3 for heating in the ten-fraction schedule. Although an increasing number of fractions tended to result in a greater recovery ratio for normal tissue damage than for tumor, this finding was not statistically significant.