Ishiyama Hiromichi, Sekiguchi Akane, Satoh Takefumi, Tsumura Hideyasu, Takenaka Kouji, Kawakami Shogo, Tabata Ken-Ichi, Kobayashi Kentaro, Iwamura Masatsugu, Hayakawa Kazushige
Department of Radiology and Radiation Oncology.
Department of Urology, Kitasato University School of Medicine, Kitasato, Sagamihara, Japan.
J Contemp Brachytherapy. 2016 Feb;8(1):7-16. doi: 10.5114/jcb.2016.57817. Epub 2016 Feb 9.
The aim of this report is dosimetric evaluation for an intraoperative fusion computed tomography (CT) as a superior predictor of 1-month CT based dosimetry in comparison to transrectal ultrasound (TRUS) in permanent interstitial prostate brachytherapy.
Data of 65 patients treated with seed implantation were analyzed. All procedures has been performed with patients in the lithotomy position inside the O-arm system. An end-fine probe is used as a landmark to fuse TRUS and O-arm-based CT images. There was no difference in the patient's position, probe position, and timing of image acquisition between the two imaging modalities. Dose-volume histogram (DVH) parameters such as the dose to 90% of prostate volume (D90) has been analyzed.
The area under the curve of the receiver operating characteristic tended to be larger on fusion CT than on TRUS for most DVH parameters (71.85% vs. 59.59% for D90; p = 0.07). Significant relationships between fusion CT and 1-month CT were confirmed using Pearson's correlation coefficients for most DVH parameters (R = 0.48, p < 0.01 for D90), although the relationship between TRUS and 1-month CT was poor. Large dose reduction (35 Gy for D90) was seen from TRUS to fusion CT, especially in patients with high body weight and small prostate volume.
Intraoperative fusion CT appears to have higher predictive power for 1-month CT-based dosimetry than TRUS. A prospective trial using fusion CT-based planning is warranted.
本报告旨在对术中融合计算机断层扫描（CT）进行剂量学评估，以确定其在永久性间质前列腺近距离治疗中，与经直肠超声（TRUS）相比，作为1个月后基于CT剂量学的更优预测指标。
分析了65例行粒子植入治疗患者的数据。所有操作均在O型臂系统内患者处于截石位时进行。使用末端精细探头作为融合TRUS和基于O型臂的CT图像的标记。两种成像方式在患者体位、探头位置和图像采集时间方面无差异。分析了剂量体积直方图（DVH）参数，如前列腺体积90%所接受的剂量（D90）。
对于大多数DVH参数，融合CT上的受试者操作特征曲线下面积往往大于TRUS（D90为71.85%对59.59%；p = 0.07）。对于大多数DVH参数，使用Pearson相关系数证实了融合CT与1个月后CT之间存在显著相关性（D90的R = 0.48，p < 0.01），尽管TRUS与1个月后CT之间的相关性较差。从TRUS到融合CT可见大量剂量降低（D90降低35 Gy），尤其是在体重高和前列腺体积小的患者中。
术中融合CT对基于1个月后CT的剂量学的预测能力似乎高于TRUS。有必要进行一项基于融合CT规划的前瞻性试验。
