单发立体定向放疗与海马回避全脑放疗治疗 10-30 个脑转移瘤患者：剂量学分析。

Single-Fraction Stereotactic Radiosurgery Versus Hippocampal-Avoidance Whole Brain Radiation Therapy for Patients With 10 to 30 Brain Metastases: A Dosimetric Analysis.

机构信息

Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.

Division of Neurosurgery, St Michaels Hospital, University of Toronto, Toronto, Ontario, Canada.

出版信息

Int J Radiat Oncol Biol Phys. 2019 Oct 1;105(2):394-399. doi: 10.1016/j.ijrobp.2019.06.2543. Epub 2019 Jul 5.

DOI:10.1016/j.ijrobp.2019.06.2543

PMID:31283978

Abstract

PURPOSE

To compare normal tissue dosimetry between hippocampal-avoidance whole brain radiation therapy (HA-WBRT) and stereotactic radiosurgery (SRS) in patients with 10 to 30 brain metastases, and to describe a novel SRS strategy we term Spatially Partitioned Adaptive RadiosurgEry (SPARE).

METHODS AND MATERIALS

A retrospective review identified SRS treatment plans with >10 brain metastases located >5 mm from the hippocampi. Our Gamma Knife Icon (GKI) SPARE (GKI-Spr) technique treats multiple metastases with single-fraction SRS partitioned over consecutive days while limiting the total treatment time to ≤60 minutes per day. Hippocampal and normal brain dosimetry were compared among GKI-Spr, single-fraction single-day GKI (GKI-Sfr), and 30 Gy in 10 fractions HA-WBRT. Dose metrics were converted to equivalent dose in 2 Gy fractions.

RESULTS

Ten cases were analyzed. Compared with HA-WBRT, GKI-Spr significantly reduced the median equivalent dose in 2 Gy fractions hippocampal maximum point dose, mean dose, and dose to 40% of the hippocampi (D40%) by 86%, 93%, and 93%, respectively, and similarly for GKI-Sfr by 81%, 92%, and 91%, respectively. The normal brain median mean dose was reduced by 95% with GKI-Spr and 94% with GKI-Sfr. Compared with GKI-Sfr, GKI-Spr further reduced all normal brain and hippocampal dose metrics (P ≤ .014).

CONCLUSIONS

GKI yields superior hippocampal and normal brain dosimetry compared with HA-WBRT, and GKI-Spr results in further dosimetric advantages.

摘要

目的

比较 10 至 30 个脑转移瘤患者行海马回避全脑放疗（HA-WBRT）和立体定向放疗（SRS）的正常组织剂量学，描述一种新的 SRS 策略，我们称之为空间分区自适应放疗（SPARE）。

方法和材料

回顾性分析了>10 个位于距海马>5mm 的脑转移瘤的 SRS 治疗计划。我们的伽玛刀 Icon（GKI）SPARE（GKI-Spr）技术采用单次分割，连续多天治疗多个转移灶，同时将每天的总治疗时间限制在≤60 分钟。比较了 GKI-Spr、单次分割单次治疗的 GKI（GKI-Sfr）和 30Gy/10 次分割的 HA-WBRT 之间的海马和正常脑剂量学。剂量指标转换为等效剂量 2Gy 分数。

结果

分析了 10 例患者。与 HA-WBRT 相比，GKI-Spr 使海马最大点剂量、平均剂量和 40%海马剂量（D40%）的等效剂量 2Gy 分数分别降低了 86%、93%和 93%，GKI-Sfr 分别降低了 81%、92%和 91%。GKI-Spr 和 GKI-Sfr 使正常脑平均剂量中位数降低了 95%和 94%。与 GKI-Sfr 相比，GKI-Spr 进一步降低了所有正常脑和海马的剂量指标（P≤.014）。