目的:伽玛刀分割手术(FGKS)最近已用于治疗大型脑转移瘤。然而,对治疗过程中病变的比容变化知之甚少。作者研究了FGKS期间转移性病变的短期体积变化。
方法:作者分析了33例40个病灶接受FGKS治疗的非小细胞肺癌(NSCLC;25例32个病灶)和乳腺癌(8例8个病灶)颅内转移的患者。FGKS在3-5个部分中进行。在第一部分之前进行基线MRI。在1或2个分数后重复MRI。基于新图像执行自适应规划。处方剂量中位数为8Gy(范围6-10Gy),等量线为50%。
结果:随访MRI,40个病变中有18个(45.0%)显示肿瘤体积(TV)减少。在基线(中位数15.8cm3)和随访(中位数14.2cm3)之间观察到显着差异(p<0.001)。当假设没有实施适应性计划时,一致性指数显著下降,从基线(平均0.96)到随访(平均0.90,p<0.001)。平均每天减少率为1.5%。中位随访时间为29.5周(范围9-94周)。在后续期间,5个病灶发生局部复发。
结论:在FGKS过程中,电视显示了高剂量辐射的变化。体积变化引起临床参数的显着差异。预期自适应规划在放射敏感性肿瘤(诸如NSCLCs或乳腺癌)的情况下将是有帮助的,以确保对目标区域的足够剂量并减少正常组织对放射的不必要暴露。
Fractionated Gamma Knife surgery (FGKS) has recently been used to treat large brain metastases. However, little is known about specific volume changes of lesions during the course of treatment. The authors investigated short-term volume changes of metastatic lesions during FGKS.
The authors analyzed 33 patients with 40 lesions who underwent FGKS for intracranial metastases of non-small-cell lung cancer (NSCLC; 25 patients with 32 lesions) and breast cancer (8 patients with 8 lesions). FGKS was performed in 3-5 fractions. Baseline MRI was performed before the first fraction. MRI was repeated after 1 or 2 fractions. Adaptive planning was executed based on new images. The median prescription dose was 8 Gy (range 6-10 Gy) with a 50% isodose line.
On follow-up MRI, 18 of 40 lesions (45.0%) showed decreased tumor volumes (TVs). A significant difference was observed between baseline (median 15.8 cm3) and follow-up (median 14.2 cm3) volumes (p < 0.001). A conformity index was significantly decreased when it was assumed that adaptive planning was not implemented, from baseline (mean 0.96) to follow-up (mean 0.90, p < 0.001). The average reduction rate was 1.5% per day. The median follow-up duration was 29.5 weeks (range 9-94 weeks). During the follow-up period, local recurrence occurred in 5 lesions.
The TV showed changes with a high dose of radiation during the course of FGKS. Volumetric change caused a significant difference in the clinical parameters. It is expected that adaptive planning would be helpful in the case of radiosensitive tumors such as NSCLCs or breast cancer to ensure an adequate dose to the target area and reduce unnecessary exposure of normal tissue to radiation.