肺癌光子与质子立体定向体部放射治疗中肿瘤位置位移的剂量学影响

Dosimetric impact of tumor position displacements between photon and proton stereotactic body radiation therapy for lung cancer.

作者信息

Chieh-Wen Liu, Tianjun Ma, Tara Gray, Saeed Ahmed, Naichang Yu, Kevin L Stephans, Gregory M M Videtic, Ping Xia

机构信息

Department of Radiation Oncology, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195, USA.

Department of Radiation Medicine, MedStar Georgetown University Hospital, 3800 Reservoir Rd NW, Washington, DC 20007, USA.

出版信息

J Radiosurg SBRT. 2022;8(2):137-146.

PMID:36275136

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9489077/

Abstract

PURPOSE

To investigate the impact of tumor position displacements (TPDs) on tumor dose coverage in photon and proton stereotactic body radiation therapy (SBRT) treatments for lung cancer patients.

METHODS

From our institutional database of 2877 fractions from 770 lung cancer patients treated with photon SBRT in 2017-2021, 163 fractions from 88 patients with recorded iso-center shifts of >1.5 cm in any direction under kV-cone-beam CT guidance were identified. By double registrations with bony and tumor alignments, the difference between the iso-center shifts of these two alignments was categorized as TPDs. One fraction from each of 15 patients who had TPD magnitudes >3 mm were selected for this study. For each patient, one proton plan using intensity modulated proton therapy (IMPT) with robust optimization was generated retrospectively. All photon plans had V>99% of GTVs and V>98% of ITVs. Proton plans were evaluated with two worse-case scenario (voxelwise worst and worst scenario) using 5mm and 3.5% uncertainty to achieve the same planning goals as the corresponding photon plans. These two evaluation proton plans were named proton-1st and proton-2nd plans. The dosimetric effect of TPD was simulated by shifting tumor contours with the corresponding shift on patient specific planning CT and by recalculating the dose of the original plan.

RESULTS

The range of magnitude of TPDs was 3.58-28.71 mm. In photon plans, TPDs did not impact tumor dose coverage, still achieving V of the GTV≥99% and V of the ITV≥98%. In proton plans for patients with TPDs>10 mm, inadequate target dose coverage was observed. More specifically, 8 fractions of proton-1st plans and 4 fractions of proton-2nd had V of the GTV<99% and V of the ITV<98%.

CONCLUSIONS

Adequate tumor dose coverage was achieved in photon SBRT for magnitude of TPDs up to 20 mm. TPDs had greater impact in proton SBRT and adaptive planning was needed when the magnitude of TPDs>10 mm to provide adequate tumor dose coverage.

摘要

目的

探讨肿瘤位置位移（TPD）对肺癌患者光子和质子立体定向体部放射治疗（SBRT）中肿瘤剂量覆盖的影响。

方法

从我们机构2017 - 2021年接受光子SBRT治疗的770例肺癌患者的2877个分次的数据库中，识别出88例在千伏锥形束CT引导下任何方向等中心移位记录>1.5 cm的患者的163个分次。通过骨骼和肿瘤配准的双重配准，将这两种配准的等中心移位差异归类为TPD。从15例TPD幅度>3 mm的患者中各选取一个分次进行本研究。对于每位患者，回顾性生成一个使用强度调制质子治疗（IMPT）并进行稳健优化的质子计划。所有光子计划的GTV的V>99%且ITV的V>98%。质子计划使用5mm和3.5%的不确定性在两种最坏情况场景（体素级最坏和最坏场景）下进行评估，以实现与相应光子计划相同的计划目标。这两个评估质子计划分别命名为质子-1计划和质子-2计划。通过在患者特定的计划CT上以相应的移位移动肿瘤轮廓并重新计算原始计划的剂量来模拟TPD的剂量学效应。