Fujioka Chiaki, Ishii Kentaro, Yamanaga Toshiko, Ogino Ryo, Kishimoto Shun, Kawamorita Ryu, Tada Takuhito, Nakajima Toshifumi
Department of Radiation Oncology, Tane General Hospital, Osaka, Japan.
Department of Radiation Oncology, Tane General Hospital, Osaka, Japan.
Pract Radiat Oncol. 2016 Nov-Dec;6(6):395-401. doi: 10.1016/j.prro.2016.05.007. Epub 2016 May 26.
To investigate optimal bladder volumes at treatment planning (TP) in prostate cancer patients who undergo volumetric modulated arc therapy (VMAT).
To determine the minimum value, 122 patients were classified into 6 groups according to the bladder volume at TP: <100 mL (group 1), 100-149 mL (group 2), 150-199 mL (group 3), 200-249 mL (group 4), 250-299 mL (group 5), and ≥300 mL (group 6). Bladder volumes receiving more than 70 Gy (V) and V were calculated in each subgroup and compared with the bladder dose-volume constraints specified in our institution. To determine the maximum value, 64 patients who underwent uniform nursing interventions were classified into the same 6 groups. Bladder volumes on cone beam computed tomography (CBCT) images were measured once weekly during treatment, for a total of 8 measurements. Relative bladder volumes (bladder volume on CBCT image [mL]/bladder volume at TP [mL] × 100%) were evaluated in each of the 6 subgroups.
The upper bounds of the 95% confidence intervals of the mean V and V values in group 1 exceeded the dose constraints at our institution. The mean relative bladder volumes were 104%, 91%, 77%, 81%, 63%, and 59% in groups 1, 2, 3, 4, 5, and 6, respectively. The institutional criterion of 70% for the mean relative bladder volume was achieved in groups 1-4, but it could not be achieved in groups 5-6. Therefore, the patients in groups 2-4 met both institutional dose constraints for the bladder at TP and the institutional criterion for the mean relative bladder volume during treatment.
The optimal bladder volumes at TP were between 100 and 250 mL in this setting. Nursing intervention needs to be implemented before treatment planning to ensure that patients achieve the optimal bladder volume range.
探讨接受容积调强弧形放疗（VMAT）的前列腺癌患者在治疗计划（TP）时的最佳膀胱容积。
为确定最小值，将122例患者根据TP时的膀胱容积分为6组：<100 mL（第1组）、100 - 149 mL（第2组）、150 - 199 mL（第3组）、200 - 249 mL（第4组）、250 - 299 mL（第5组）和≥300 mL（第6组）。计算每个亚组中接受超过70 Gy的膀胱容积（V）和V，并与本机构规定的膀胱剂量 - 容积限制进行比较。为确定最大值，将64例接受统一护理干预的患者分为相同的6组。在治疗期间每周一次在锥形束计算机断层扫描（CBCT）图像上测量膀胱容积，共测量8次。在6个亚组中分别评估相对膀胱容积（CBCT图像上的膀胱容积[mL]/TP时的膀胱容积[mL]×100%）。
第1组中平均V和V值的95%置信区间上限超过了本机构的剂量限制。第1、2、3、4、5和6组的平均相对膀胱容积分别为104%、91%、77%、81%、63%和59%。第1 - 4组达到了本机构平均相对膀胱容积70%的标准，但第5 - 6组未达到。因此，第2 - 4组患者在TP时满足本机构对膀胱的剂量限制以及治疗期间平均相对膀胱容积的机构标准。
在这种情况下，TP时的最佳膀胱容积在100至250 mL之间。在治疗计划前需要实施护理干预，以确保患者达到最佳膀胱容积范围。
