Ohashi Toshio, Yorozu Atsunori, Toya Kazuhito, Saito Shiro, Momma Tetsuo, Nagata Hirohiko, Kosugi Michio, Shigematsu Naoyuki, Kubo Atsushi
Department of Radiology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
Brachytherapy. 2007 Oct-Dec;6(4):246-53. doi: 10.1016/j.brachy.2007.08.006. Epub 2007 Oct 23.
To compare the results of intraoperative dosimetry with those of postimplant computed tomography (CT)-based dosimetry after (125)I prostate brachytherapy.
We treated 412 prostate cancer patients with (125)I prostate brachytherapy, with or without external beam radiotherapy at our institution. Neoadjuvant hormone therapy was administered to 331 patients (80.3%). Implantation was performed using an intraoperative interactive technique. Postimplant dosimetry was performed on Day 1 and Day 30 using CT imaging. The dosimetric results for the prostate, urethra, and rectum were compared among intraoperative ultrasound, and CT scans of Day 1 and Day 30.
The mean intraoperative minimal dose received by 90% of the prostate volume (D(90)) was 118.8% of the prescribed dose vs. 106.4% for Day 1 (p < 0.01) and 119.2% for Day 30 (p = 0.25). There were no significant correlations between the intraoperative D(90) and the postimplant D(90) values (intraclass correlation coefficients=0.42 and 0.33 for Day 1 and Day 30, respectively). Prostatic edema at Day 1 had the largest effect on the Day 1 D(90) (p < 0.01). The factor significantly affecting the Day 30 D(90) was neoadjuvant hormone therapy (p < 0.01). The mean Day 30 D(90) for the hormone-treated patients was 117.9%, compared with 124.6% for those who remained hormone naïve. The intraoperative and postimplant dosimetric values differed significantly for the urethra and rectum.
Our results demonstrate that there are no significant differences between the D(90) assessments obtained intraoperatively and at Day 30 postoperatively. Furthermore, there are no definite correlations between intra- and postimplantation dosimetric values. Other D(90) values differed significantly between the intraoperative and postimplant dosimetry. This study suggests that dosimetry has negligible clinical utility for informing patients, at discharge, of whether or not their implants are adequate.
比较¹²⁵I前列腺近距离治疗术中剂量测定结果与植入后基于计算机断层扫描（CT）的剂量测定结果。
我们对412例前列腺癌患者进行了¹²⁵I前列腺近距离治疗，在我们机构中部分患者联合或不联合外照射放疗。331例患者（80.3%）接受了新辅助激素治疗。采用术中交互式技术进行植入。在第1天和第30天使用CT成像进行植入后剂量测定。比较术中超声以及第1天和第30天CT扫描的前列腺、尿道和直肠的剂量测定结果。
前列腺体积的90%所接受的术中平均最小剂量（D₉₀）为处方剂量的118.8%，而第1天为106.4%（p<0.01），第30天为119.2%（p = 0.25）。术中D₉₀与植入后D₉₀值之间无显著相关性（第1天和第30天的组内相关系数分别为0.42和0.33）。第1天的前列腺水肿对第1天的D₉₀影响最大（p<0.01）。显著影响第30天D₉₀的因素是新辅助激素治疗（p<0.01）。接受激素治疗患者的第30天平均D₉₀为117.9%，而未接受激素治疗患者为124.6%。术中与植入后尿道和直肠的剂量测定值差异显著。
我们的结果表明，术中与术后第30天获得的D₉₀评估之间无显著差异。此外，植入前和植入后剂量测定值之间无明确相关性。术中与植入后剂量测定的其他D₉₀值差异显著。本研究表明，剂量测定对于告知患者出院时其植入物是否合适的临床效用可忽略不计。
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