CyberKnife 是否比线性加速器的 IMRT 和 VMAT 更能改善低危前列腺癌的剂量分布？

Does CyberKnife improve dose distribution versus IMRT and VMAT on a linear accelerator in low-risk prostate cancer?

机构信息

Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland.

Electroradiology Department, University of Medical Sciences, Poznan, Poland.

出版信息

Radiol Oncol. 2022 Mar 28;56(2):259-266. doi: 10.2478/raon-2022-0010.

DOI:10.2478/raon-2022-0010

PMID:35344646

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9122296/

Abstract

BACKGROUND

Hypofractionated stereotactic body radiation therapy (SBRT) for prostate cancer (PCa) can be delivered with the robot-assisted CyberKnife (CK) system or on a linear accelerator using dynamic intensity-modulated radiotherapy (IMRT) or volumetric arc radiotherapy (VMAT). This retrospective study was performed to determine whether CK offers better dose distribution than IMRT and/or VMAT.

MATERIALS AND METHODS

Treatment plans for three techniques were prepared using the same treatment parameters (36.35 Gy, 7.25 Gy/fr). We evaluated target coverage, conformity index (CI), homogeneity index (HI), gamma index (GI), and organs at risk (OAR) constraints.

RESULTS

The mean planning target volume (PTV) dose for CK (39.58 Gy) was significantly greater than VMAT or IMRT (both 36.25 Gy). However, CK resulted in a wider dose range (31.48 to 45.89 Gy) . VMAT and IMRT (34.6-38.76 Gy). The mean dose to the rectum (V36Gy, mm) was significantly lower (p < 0.001) in the CK plans (219.78 . 519.59 and 422.62, respectively). The mean bladder dose (V37Gy, mm) was significantly greater for CK (3256 . 1090.75 for VMAT and 4.5 for IMRT (p < 0.001). CK yielded significantly better CI (1.07 . 1.17 and 1.25 for VMAT and IMRT, respectively; p < 0.01) and HI values (1.27 . 1.07 and 1.04; p < 0.01). GI values for the δd = 3mm, δ% = 3% criteria were 99.86 (VMAT), 99.07 (IMRT) and 99.99 (CK). For δd = 2mm, δ% = 2%, the corresponding values were 98.3, 93.35, and 97.12, respectively.

CONCLUSIONS

For most variables, CK was superior to both VMAT and IMRT. However, dynamic IMRT techniques, especially VMAT, do not differ significantly from CK plans and are therefore acceptable alternatives to CyberKnife.

摘要

背景

前列腺癌（PCa）的分割立体定向体放射治疗（SBRT）可以通过机器人辅助的 CyberKnife（CK）系统或使用动态强度调制放射治疗（IMRT）或容积弧形放射治疗（VMAT）的线性加速器来完成。这项回顾性研究旨在确定 CK 是否提供了比 IMRT 和/或 VMAT 更好的剂量分布。

材料和方法

使用相同的治疗参数（36.35 Gy，7.25 Gy/fr）为三种技术准备治疗计划。我们评估了靶区覆盖、适形指数（CI）、均匀性指数（HI）、伽马指数（GI）和危及器官（OAR）限制。

结果

CK 的平均计划靶区（PTV）剂量（39.58 Gy）明显大于 VMAT 或 IMRT（均为 36.25 Gy）。然而，CK 导致的剂量范围更宽（31.48 至 45.89 Gy），VMAT 和 IMRT 的剂量范围为 34.6 至 38.76 Gy。直肠（V36Gy，mm）的平均剂量明显更低（p < 0.001），CK 方案分别为 219.78、519.59 和 422.62。膀胱的平均剂量（V37Gy，mm）明显更高（p < 0.001），CK 为 3256、1090.75，VMAT 为 4.5，IMRT 为 4.5。CK 的 CI（1.07、1.17 和 1.25，VMAT 和 IMRT 分别；p < 0.01）和 HI 值（1.27、1.07 和 1.04；p < 0.01）明显更好。对于 δd = 3mm，δ% = 3% 的 GI 值，VMAT 为 99.86，IMRT 为 99.07，CK 为 99.99。对于 δd = 2mm，δ% = 2%，相应的值分别为 98.3、93.35 和 97.12。