Department of Radiology, Keio University, School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582 Japan.
J Radiat Res. 2012 Sep;53(5):753-9. doi: 10.1093/jrr/rrs020. Epub 2012 Jul 5.
We investigated the usefulness of the fusion image created by transrectal ultrasonography (TRUS) and large-bore computed tomography (CT) for predicting pubic arch interference (PAI) during prostate seed brachytherapy. The TRUS volume study was performed in 21 patients, followed by large-bore computed tomography of patients in the lithotomy position. Then, we created TRUS-CT fusion images using a radiation planning treatment system. TRUS images in which the prostate outline was the largest were overlaid on CT images with the narrowest pubic arch. PAI was estimated in the right and left arch separately and classified to three grades: no PAI, PAI positive within 5 mm and PAI of >5 mm. If the estimated PAI was more than 5 mm on at least one side of the arch, we judged there to be a significant PAI. Brachytherapy was performed in 18 patients who were evaluated as not having significant PAI on TRUS. Intra-operative PAI was observed in one case, which was also detected with a fusion image. On the other hand, intra-operative PAI was not observed in one case that had been evaluated as having significant PAI with a fusion image. In the remaining three patients, TRUS suggested the presence of significant PAI, which was also confirmed by a fusion image. Intra-operative PAI could be predicted by TRUS-CT fusion imaging, even when it was undetectable by TRUS. Although improvement of the reproducibility of the patients' position to avoid false-positive cases is warranted, TRUS-CT fusion imaging has the possibility that the uncertainty of TRUS can be supplemented.
我们研究了经直肠超声（TRUS）和大口径计算机断层扫描（CT）融合图像在预测前列腺种子近距离放射治疗中耻骨弓干扰（PAI）的有用性。在 21 名患者中进行了 TRUS 体积研究，然后让患者处于截石位进行大口径 CT 检查。然后，我们使用放射治疗计划系统创建了 TRUS-CT 融合图像。将前列腺轮廓最大的 TRUS 图像叠加在耻骨弓最窄的 CT 图像上。分别估计左右弓的 PAI，并将其分为三个等级：无 PAI、PAI 阳性<5mm 和 PAI>5mm。如果至少一侧弓的估计 PAI>5mm，则判断存在明显的 PAI。对 18 名经 TRUS 评估无明显 PAI 的患者进行近距离放射治疗。在一个病例中观察到术中 PAI，该病例也通过融合图像检测到。另一方面，在一个经融合图像评估为有明显 PAI 的病例中，未观察到术中 PAI。在其余 3 名患者中，TRUS 提示存在明显 PAI，融合图像也证实了这一点。即使通过 TRUS 无法检测到，TRUS-CT 融合成像也可以预测术中 PAI。尽管需要改善患者体位的可重复性以避免假阳性病例，但 TRUS-CT 融合成像有可能补充 TRUS 的不确定性。
