Jarvis Lesley A, Hachadorian Rachael L, Jermyn Michael, Bruza Petr, Alexander Daniel A, Tendler Irwin I, Williams Benjamin B, Gladstone David J, Schaner Philip E, Zaki Bassem I, Pogue Brian W
Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
Thayer School of Engineering at Dartmouth, Hanover, New Hampshire.
Int J Radiat Oncol Biol Phys. 2021 Apr 1;109(5):1627-1637. doi: 10.1016/j.ijrobp.2020.11.013. Epub 2020 Nov 20.
The value of Cherenkov imaging as an on-patient, real-time, treatment delivery verification system was examined in a 64-patient cohort during routine radiation treatments in a single-center study.
Cherenkov cameras were mounted in treatment rooms and used to image patients during their standard radiation therapy regimen for various sites, predominantly for whole breast and total skin electron therapy. For most patients, multiple fractions were imaged, with some involving bolus or scintillators on the skin. Measures of repeatability were calculated with a mean distance to conformity (MDC) for breast irradiation images.
In breast treatments, Cherenkov images identified fractions when treatment delivery resulted in dose on the contralateral breast, the arm, or the chin and found nonideal bolus positioning. In sarcoma treatments, safe positioning of the contralateral leg was monitored. For all 199 imaged breast treatment fields, the interfraction MDC was within 7 mm compared with the first day of treatment (with only 7.5% of treatments exceeding 3 mm), and all but 1 fell within 7 mm relative to the treatment plan. The value of imaging dose through clear bolus or quantifying surface dose with scintillator dots was examined. Cherenkov imaging also was able to assess field match lines in cerebral-spinal and breast irradiation with nodes. Treatment imaging of other anatomic sites confirmed the value of surface dose imaging more broadly.
Daily radiation therapy can be imaged routinely via Cherenkov emissions. Both the real-time images and the posttreatment, cumulative images provide surrogate maps of surface dose delivery that can be used for incident discovery and/or continuous improvement in many delivery techniques. In this initial 64-patient cohort, we discovered 6 minor incidents using Cherenkov imaging; these otherwise would have gone undetected. In addition, imaging provides automated, quantitative metrics useful for determining the quality of radiation therapy delivery.
在一项单中心研究中，对64名患者进行常规放射治疗期间，研究了切伦科夫成像作为一种患者端实时治疗交付验证系统的价值。
将切伦科夫相机安装在治疗室中，用于在患者进行各种部位的标准放射治疗方案期间对其进行成像，主要用于全乳和全皮肤电子治疗。对于大多数患者，对多个分次进行成像，有些涉及皮肤表面的 bolus 或闪烁体。通过计算乳房照射图像的平均符合距离（MDC）来衡量重复性。
在乳房治疗中，切伦科夫图像可识别出治疗交付导致对侧乳房、手臂或下巴受量时的分次情况，并发现 bolus 定位不理想。在肉瘤治疗中，监测对侧腿部的安全定位。对于所有199个成像的乳房治疗野，与治疗第一天相比，分次间 MDC 在7毫米以内（只有7.5%的治疗超过3毫米），除1个外，所有与治疗计划相比均在7毫米以内。研究了通过透明 bolus 成像剂量或用闪烁体点量化表面剂量的价值。切伦科夫成像还能够评估脑脊髓和带淋巴结乳房照射中的野匹配线。对其他解剖部位的治疗成像更广泛地证实了表面剂量成像的价值。
可通过切伦科夫发射对每日放射治疗进行常规成像。实时图像和治疗后累积图像均可提供表面剂量交付的替代图，可用于发现事件和/或持续改进多种交付技术。在这个初始的64名患者队列中，我们使用切伦科夫成像发现了6起小事件；否则这些事件将未被发现。此外，成像提供了用于确定放射治疗交付质量的自动化定量指标。
