Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Phys Med Biol. 2011 Feb 7;56(3):703-19. doi: 10.1088/0031-9155/56/3/011.
Post-operative radiotherapy has commonly been used for early stage breast cancer to treat residual disease. The primary objective of this work was to characterize, through dosimetric and radiobiological modeling, a novel focal brachytherapy technique which uses direct intracavitary infusion of β-emitting radionuclides (186Re/188Re) carried by lipid nanoparticles (liposomes). Absorbed dose calculations were performed for a spherical lumpectomy cavity with a uniformly injected activity distribution using a dose point kernel convolution technique. Radiobiological indices were used to relate predicted therapy outcome and normal tissue complication of this technique with equivalent external beam radiotherapy treatment regimens. Modeled stromal damage was used as a measure of the inhibition of the stimulatory effect on tumor growth driven by the wound healing response. A sample treatment plan delivering 50 Gy at a therapeutic range of 2.0 mm for 186Re-liposomes and 5.0 mm for 188Re-liposomes takes advantage of the dose delivery characteristics of the β-emissions, providing significant EUD (58.2 Gy and 72.5 Gy for 186Re and 188Re, respectively) with a minimal NTCP (0.046%) of the healthy ipsilateral breast. Modeling of kidney BED and ipsilateral breast NTCP showed that large injected activity concentrations of both radionuclides could be safely administered without significant complications.
术后放疗常用于治疗早期乳腺癌的残留疾病。这项工作的主要目的是通过剂量学和放射生物学建模来描述一种新的聚焦近距离放射治疗技术，该技术使用β发射放射性核素（186Re/188Re）通过脂质纳米粒（脂质体）直接腔内输注。使用剂量点核卷积技术，对球形乳房切除术腔进行了均匀注入活性分布的吸收剂量计算。使用放射生物学指数来将这种技术的预测治疗结果和正常组织并发症与等效的外部束放射治疗方案联系起来。模拟的基质损伤被用作衡量由伤口愈合反应驱动的对肿瘤生长的刺激作用的抑制程度的指标。一个治疗计划为 50Gy，在 2.0mm 的治疗范围内为 186Re-脂质体，在 5.0mm 的治疗范围内为 188Re-脂质体，利用β发射的剂量传递特性，为 186Re 和 188Re 分别提供了显著的 EUD（58.2Gy 和 72.5Gy），健康对侧乳房的 NTCP（0.046%）最小。肾脏 BED 和对侧乳房 NTCP 的建模表明，两种放射性核素的大注入活性浓度都可以安全地给予，而不会产生显著的并发症。
