Decker S M, Andreozzi J M, Hernandez D, Alexander D A, Wickramasinghe V, Hachadorian R L, Oraiqat I M, Chen E, Washington I R, Gui J, Zhang R, Jarvis L A, Bruza P, Gladstone D J, Pogue B W
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, United States of America.
Moffitt Cancer Center, Tampa, FL 33612, United States of America.
Phys Med Biol. 2025 Jul 29;70(15). doi: 10.1088/1361-6560/aded68.
. Cherenkov imaging is an emerging technology that detects light naturally emitted from patient tissue during radiation treatment. The initial intensity of Cherenkov light is proportional to radiation dose, but its absorption is highly dependent on patient skin pigmentation, with increasing melanin attenuating more Cherenkov photons per dose. This effect must be calibrated per patient before Cherenkov emission can serve as an accurate surrogate for dose. In this study, we present the first attempt atCherenkov imaging of a diverse patient cohort and calibration for the effect of skin pigmentation towards quantitative Cherenkov dosimetry.. A multi-institutional collaboration was designed to increase the diversity of our patient imaging cohort. Cherenkov imaging was completed with a time-gated, iCMOS camera, and color background images were taken with an RGB camera module under standardized lighting. Under an institutional review board-approved retrospective protocol, skin pigmentation was assessed per patient by calculating the relative luminance of their treated area from the color images. Additionally, 2D dose maps were generated by projecting the exponentially-weighted dose from the surface to 5 mm into the body, representative of Cherenkov emission.Of= 23 and= 20 breast patients imaged, encompassing a variety of skin pigmentations, Cherenkov intensity varied nearly 5X for the same dose delivered across the examined cohort. Plotting Cherenkov intensity per unit dose revealed a direct correlation with relative luminance, providing a linear calibration factor based on skin pigmentation. Including this calibration factor significantly improved Cherenkov-to-dose linearity, from= 0.79-0.96 for 6 MV and= 0.19-0.91 for 15 MV (< 0.05).. This study marks the first assessment of Cherenkov imaging in a diverse, representative patient population. It addresses an integral factor towards achieving quantitativeCherenkov dosimetry and demonstrates significant mitigation of the effect of skin pigmentation, while preserving the non-contact, real-time benefits of Cherenkov imaging.
切伦科夫成像技术是一项新兴技术，可检测放射治疗期间患者组织自然发出的光。切伦科夫光的初始强度与辐射剂量成正比，但其吸收高度依赖于患者的皮肤色素沉着，黑色素含量增加会使每剂量的切伦科夫光子衰减更多。在切伦科夫发射能够作为剂量的准确替代指标之前，必须针对每位患者进行这种效应的校准。在本研究中，我们首次尝试对不同患者群体进行切伦科夫成像，并针对皮肤色素沉着对定量切伦科夫剂量测定的影响进行校准。开展了一项多机构合作，以增加我们患者成像群体的多样性。使用时间门控的iCMOS相机完成切伦科夫成像，并在标准化照明条件下使用RGB相机模块拍摄彩色背景图像。根据机构审查委员会批准的回顾性方案，通过计算彩色图像中患者治疗区域的相对亮度来评估每位患者的皮肤色素沉着情况。此外，通过将从表面到体内5毫米的指数加权剂量进行投影来生成二维剂量图，代表切伦科夫发射情况。在成像的23例乳腺癌患者和20例患者中，涵盖了各种皮肤色素沉着情况，对于整个检查队列中相同剂量的辐射，切伦科夫强度变化近5倍。绘制每单位剂量的切伦科夫强度与相对亮度呈直接相关性，从而提供了基于皮肤色素沉着的线性校准因子。纳入该校准因子显著改善了切伦科夫强度与剂量的线性关系，对于6兆伏的情况，相关系数从0.79提高到0.96，对于15兆伏的情况，从0.19提高到0.91（P<0.05）。本研究标志着首次在多样化的代表性患者群体中对切伦科夫成像进行评估。它解决了实现定量切伦科夫剂量测定的一个不可或缺的因素，并在保留切伦科夫成像非接触、实时优势的同时，显著减轻了皮肤色素沉着的影响。
