Bajon Tomasz, Piotrowski Tomasz, Antczak Andrzej, Bąk Bartosz, Błasiak Barbara, Kaźmierska Joanna
II Radiotherapy Department, Greater Poland Cancer Centre, Poland.
Department of Medical Physics, Greater Poland Cancer Centre, Poland.
Rep Pract Oncol Radiother. 2011 Feb 1;16(2):65-70. doi: 10.1016/j.rpor.2011.01.003. eCollection 2011.
To compare DVHs for OARs in two different positions - prone and supine - for prostate cancer patients irradiated with a Tomotherapy unit.
In the era of dose escalation, the choice of optimal patient immobilization plays an essential role in radiotherapy of prostate cancer.
The study included 24 patients who were allocated to 3 risk groups based on D'Amico criteria; 12 patients represented a low or intermediate and 12 a high risk group. FOR EACH PATIENT TWO TREATMENT PLANS WERE PERFORMED: one in the supine and one in the prone position. PTV included the prostate, seminal vesicles and lymph nodes for the high risk group and the prostate and seminal vesicles for the intermediate or low risk groups. DVHs for the two positions were compared according to parameters: Dmean, D70, D50 and D20 for the bladder and rectum and Dmean, D10 for the intestine. The position accuracy was verified using daily MVCT.
Prone position was associated with lower doses in OARs, especially in the rectum. Despite the fact that in the entire group the differences between tested parameters were not large, the Dmean and D10 for the intestine were statistically significant. In the case of irradiation only to the prostate and seminal vesicles, the prone position allowed for substantial reduction of all tested DVH parameters in the bladder and rectum, except D20 for bladder. Moreover, the Dmean and D50 parameter differences for the bladder were statistically significant. No significant differences between positions reproducibility were demonstrated.
In patients irradiated to prostate and seminal vesicles, the prone position may support sparing of the rectum and bladder. The reproducibility of position arrangement in both positions is comparable.
比较使用螺旋断层放疗设备对前列腺癌患者进行俯卧位和仰卧位两种不同体位照射时危及器官的剂量体积直方图（DVH）。
在剂量递增时代，选择最佳的患者固定方式在前列腺癌放疗中起着至关重要的作用。
该研究纳入24例患者，根据达米科标准将其分为3个风险组；12例为低或中危组，12例为高危组。对每位患者进行两种治疗计划：一种为仰卧位，一种为俯卧位。高危组的计划靶体积（PTV）包括前列腺、精囊和淋巴结，中低危组的PTV包括前列腺和精囊。根据膀胱和直肠的平均剂量（Dmean）、70%处方剂量（D70）、50%处方剂量（D50）、20%处方剂量（D20）以及肠道的Dmean、10%处方剂量（D10）等参数比较两种体位的DVH。使用每日兆伏级计算机断层扫描（MVCT）验证体位准确性。
俯卧位与危及器官较低剂量相关，尤其是直肠。尽管在整个组中测试参数之间的差异不大，但肠道的Dmean和D10具有统计学意义。在仅照射前列腺和精囊的情况下，俯卧位可使膀胱和直肠中所有测试的DVH参数大幅降低，膀胱的D20除外。此外，膀胱的Dmean和D50参数差异具有统计学意义。两种体位的重复性未显示出显著差异。
在接受前列腺和精囊照射的患者中，俯卧位可能有助于减少直肠和膀胱受量。两种体位的体位设置重复性相当。
