Department of Radiation Oncology, St. Luke's International Hospital, Tokyo, Japan.
Strahlenther Onkol. 2010 Nov;186(11):637-42. doi: 10.1007/s00066-010-2105-6. Epub 2010 Nov 8.
To evaluate variation in bladder volume of full bladders in definitive radiotherapy for localized prostate cancer and to investigate potential predictors of increased bladder volume variations.
In 40 patients, the bladder volume was measured with megavoltage computed tomography (MVCT) imaging performed just before irradiation during the administration of the 1st fraction (#1), the 10th fraction (#10), the 20th fraction (#20), and the 30th fraction (#30). Patients were instructed to avoid urinating for 60-90 minutes before the planning CT (pln-CT) scan and before daily irradiation. Patients were also encouraged to drink an unspecified volume of liquid that would result in a clear but tolerable urge to urinate.
The population-mean bladder volume (±1SD) was 219 ml (±83 ml) at the planning CT scan (pln-CT), 186 ml (±96 ml) at #1, 149 ml (±73 ml) at #10, 137 ml (±59 ml) at #20, and 136 ml (±60 ml) at #30. The mean intrapatient variation in bladder volume (1 SD relative to the mean bladder volume of each patient) was 38% (range: 10-84%). The bladder volume at the pln-CT was correlated with the intrapatient variance in bladder volume with a correlation coefficient of 0.54 and p <0.001.
We observed a significant decline in bladder volumes during the course of radiotherapy. The bladder volume at the pln-CT was a significant predictor of increased bladder volume variations.
评估局部前列腺癌根治性放疗中充盈膀胱的膀胱体积变化，并探讨膀胱体积变化增加的潜在预测因素。
在 40 例患者中，在照射前第 1 次（#1）、第 10 次（#10）、第 20 次（#20）和第 30 次（#30）分次时，通过兆伏 CT（MVCT）成像测量膀胱体积。患者在计划 CT（pln-CT）扫描前和每天照射前被指示避免排尿 60-90 分钟。还鼓励患者饮用一定量的液体，使患者产生清晰但可忍受的尿意。
pln-CT 扫描时的人群平均膀胱体积（±1SD）为 219ml（±83ml），#1 时为 186ml（±96ml），#10 时为 149ml（±73ml），#20 时为 137ml（±59ml），#30 时为 136ml（±60ml）。膀胱体积的个体内变异（相对于每个患者的平均膀胱体积的 1SD）为 38%（范围：10-84%）。pln-CT 时的膀胱体积与个体内膀胱体积变异呈正相关，相关系数为 0.54（p<0.001）。
我们观察到放疗过程中膀胱体积明显下降。pln-CT 时的膀胱体积是膀胱体积变化增加的显著预测因素。
