摘要目的:基于前列腺特异性膜抗原正电子发射体层成像(PSMA PET)呈现的前列腺癌根治性切除术后局部复发的规律，探讨放射治疗肿瘤学组(RTOG)、泌尿外科放射治疗法语组(GFRU)、欧洲放射治疗与肿瘤学组(ESTRO)指南中临床靶区(CTV)勾画的优化空间，并提出改进建议。方法:回顾性分析北京大学第一医院核医学科2021年9月至2024年2月期间接受PSMA PET检查的前列腺癌术后术床局部复发的患者，标记每个复发灶的中心点。基于术床解剖和横断面影像学特征建立六分区法，记录复发灶与RTOG、GFRU、ESTRO指南所定义的CTV RTOG、CTV GFRU、CTV ESTRO的位置关系(区域内或外)，分析各区复发率及病灶分布特征。 结果:纳入了63例前列腺癌术后局部复发患者，共计97个复发灶，六分区复发率分别为1区(10%)、2区(22%)、3区(29%)、4区(2%)、5a区(12%)、5b区(18%)和6区(7%)。其中，3区和2区分别是复发率最高和其次的区域。CTV GFRU和CTV ESTRO完全覆盖了2区和3区，CTV RTOG完全覆盖了2区，部分覆盖3区。4区复发率较低，CTV GFRU和CTV ESTRO未覆盖4区，然而CTV RTOG完全覆盖了4区。5a区复发率12%，CTV RTOG完全覆盖了5a区的病灶，但是CTV GFRU和CTV ESTRO未完全覆盖5a区的病灶。在距离膀胱后壁最后缘向前1.3 cm的范围可覆盖5a区全部的复发灶。 结论:勾画前列腺癌术床靶区时，4区即耻骨联合1/2处以上膀胱前1/2的区域复发率低，应适当缩小。耻骨联合1/2处以上的前界应勾画至膀胱后壁前缘1.3 cm处，以更好地包含复发区域。

abstractsObjective:To explore the optimization potential of clinical target volume (CTV) delineation proposed in the guidelines of the Oncology Group (RTOG), the Francophone Group of Urological Radiotherapy (GFRU), and the European Society for Radiotherapy and Oncology (ESTRO) based on prostate bed local occurrence patterns after radical prostatectomy identified using prostate-specific membrane antigen positron emission tomography (PSMA PET).Methods:A retrospective analysis was conducted on patients with local prostate bed recurrence after radical prostatectomy who underwent PSMA PET at the Department of Nuclear Medicine, Peking University First Hospital from September 2021 to February 2024. The central point of each recurrence was marked. A six-zone method was established based on prostate bed anatomy and the characteristics of cross-sectional imaging. Then, the positional relationships (within or outside) were recorded with respect to recurrences and CTV defined by the RTOG, GFRU, and ESTRO (CTV RTOG, CTV GFRU, and CTV ESTRO), followed the analysis of the recurrence rates and distribution characteristics of various zones. Results:A total of 63 patients with prostate bed recurrence after radical prostatectomy were enrolled in this study, including 97 recurrences. The recurrence rates in the six zones were as follows: 10% of zone 1, 22% of zone 2, 29% of zone 3, 2% of zone 4, 12% of zone 5a, 18% of zone 5b, and 7% of zone 6. Among these zones, zones 2 and 3 showed the highest and second-highest recurrence rates, respectively. CTV GFRU and CTV ESTRO completely covered zones 2 and 3, while CTV RTOG covered zone 2 completely and zone 3 partially. Zone 4, characterized by a low recurrence rate, was not covered by CTV GFRU and CTV ESTRO but was entirely covered by CTV RTOG. Zone 5a, with a recurrence rate of 12%, was completely covered by CTV RTOG but was partially covered by CTV GFRU and CTV ESTRO. The range of 1.3 cm in front of the posterior wall of the bladder covered all recurrences in zone 5a. Conclusions:For CTV delineation of the prostate cancer surgical bed, zone 4, the anterior half of the bladder above the pubic symphysis midpoint, should be contracted due to the low recurrence rate in this zone. In contrast, the anterior boundary above the pubic symphysis midpoint should extend to 1.3 cm in front of the posterior wall of the bladder to completely cover the recurrence zones.