Steeves R A, Tompkins D T, Nash R N, Blair J R, Gentry L L, Paliwal B R, Murray T G, Mieler W F
Department of Human Oncology, University of Wisconsin-Madison, USA.
Int J Radiat Oncol Biol Phys. 1995 Oct 15;33(3):659-62. doi: 10.1016/0360-3016(95)00206-E.
To compare concurrent vs. sequential ferromagnetic thermoradiotherapy in vivo.
Greene melanomas were implanted subretinally in rabbits and observed until they were 3-5 mm in diameter. Episcleral plaques were assembled with 125I seeds for radiation therapy, or with ferromagnetic (FM) thermoseeds and nonradioactive I seeds for hyperthermia. Rabbits were implanted by centering a plaque over the intraocular melanoma. After a given dose of radiation had been delivered, the plaque was removed and a nonradioactive plaque containing FM thermoseeds was inserted into the same extrascleral space. One hour later, hyperthermia (46-47 degrees C at the plaque-scleral interface) was initiated and continued for a period of 1 h by placing the rabbits in a magnetic induction coil powered to 1200 W. Tumor size was determined at 1- to 2-week intervals by indirect ophthalmoscopy and by ultrasound.
Dose-response analysis of 27 treated eye melanomas showed 50% local tumor control at 43 Gy for 125I alone and 29.4 Gy for 125I followed by FM hyperthermia. The thermal enhancement ratio was 1.4.
Comparison with a previously published thermal enhancement ratio of 4.4 (for concurrent 125I and FM hyperthermia) leads us to conclude that thermal enhancement of 125I brachytherapy is more efficient in this tumor model system when hyperthermia is delivered during, rather than after, the irradiation process.
在体内比较同步与序贯铁磁热放疗。
将格林黑色素瘤植入兔视网膜下，观察至其直径达3 - 5毫米。用125I种子组装巩膜外斑块用于放射治疗，或用铁磁（FM）热种子和非放射性碘种子组装用于热疗。通过将斑块置于眼内黑色素瘤上方来植入兔子。在给予一定剂量的辐射后，移除斑块并将含有FM热种子的非放射性斑块插入相同的巩膜外间隙。一小时后，通过将兔子置于功率为1200 W的磁感应线圈中开始热疗（斑块 - 巩膜界面处温度为46 - 47摄氏度），并持续1小时。每隔1 - 2周通过间接检眼镜检查和超声确定肿瘤大小。
对27只接受治疗的眼黑色素瘤进行剂量 - 反应分析显示，单独使用125I时，43 Gy可实现50%的局部肿瘤控制；125I后接FM热疗时，29.4 Gy可实现50%的局部肿瘤控制。热增强比为1.4。
与先前发表的热增强比4.4（同步125I和FM热疗）相比，我们得出结论，在该肿瘤模型系统中，当热疗在照射过程中而非照射后进行时，125I近距离放疗的热增强更有效。
