Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University Health System, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, Republic of Korea.
BMC Cancer. 2020 Oct 1;20(1):942. doi: 10.1186/s12885-020-07405-z.
Despite detailed instruction for full bladder, patients are unable to maintain consistent bladder filling during a 5-week pelvic radiation therapy (RT) course. We investigated the best bladder volume estimation procedure for verifying consistent bladder volume.
We reviewed 462 patients who underwent pelvic RT. Biofeedback using a bladder scanner was conducted before simulation and during treatment. Exact bladder volume was calculated by bladder inner wall contour based on CT images (V). Bladder volume was estimated either by bladder scanner (V) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (V). The feasibility of V was validated using daily megavoltage or kV cone-beam CT before treatment.
Mean V was 335.6 ± 147.5 cc. Despite a positive correlation between V and V (R = 0.278) and between V and V (R = 0.424), V yielded more consistent results than V, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between V and V was stronger than that between V and V (Z-score: - 7.782, p < 0.001). An accuracy of V was consistent in megavoltage or kV cone-beam CT during treatment. In a representative case, we can dichotomize for clinical scenarios with or without bowel displacement, using a ratio of 0.8 resulting in significant changes in bowel volume exposed to low radiation doses.
Bladder volume estimation using personalized anatomical features based on pre-treatment verification CT images was useful and more accurate than physician-dependent bladder scanners.
Retrospectively registered.
尽管对患者进行了详细的充盈膀胱指导，但在 5 周盆腔放射治疗（RT）过程中，患者仍无法始终保持膀胱充盈。我们研究了最佳的膀胱容量估计程序，以验证膀胱容量的一致性。
我们回顾了 462 例接受盆腔 RT 的患者。在模拟和治疗期间，使用膀胱扫描仪进行了生物反馈。根据 CT 图像（V）计算膀胱内轮廓的精确膀胱容量。通过膀胱扫描仪（V）或 CT 矢状位骶前突至膀胱基底和穹窿的解剖特征（V）估计膀胱容量。在治疗前，使用每日兆伏或千伏锥形束 CT 验证 V 的可行性。
平均 V 为 335.6±147.5cc。尽管 V 与 V（R=0.278）和 V 与 V（R=0.424）之间存在正相关，但 V 的结果更一致，平均误差百分比为 26.3（SD 19.6，p<0.001）。V 与 V 之间的相关性强于 V 与 V 之间的相关性（Z 分数：-7.782，p<0.001）。在治疗期间，V 在兆伏或千伏锥形束 CT 中的准确性是一致的。在一个代表性病例中，我们可以使用比值为 0.8 对存在或不存在肠移位的临床情况进行二分类，这导致暴露于低剂量辐射的肠体积发生显著变化。
基于治疗前验证 CT 图像的个性化解剖特征的膀胱容量估计既有用又比依赖医生的膀胱扫描仪更准确。
回顾性注册。
