Lee Junghoon, Hobbs Robert F, Zahurak Marianna, Ng Sook Kien, Zhang Zhe, Burdette E Clif, DeWeese Theodore L, Song Daniel Y
Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD.
Department of Oncology, Biostatistics, Johns Hopkins University School of Medicine, Baltimore, MD.
Brachytherapy. 2018 Nov-Dec;17(6):858-865. doi: 10.1016/j.brachy.2018.07.013. Epub 2018 Sep 11.
To assess the performance of a system of intraoperative dosimetry and obtain estimates of dosimetry outcomes achieved when utilizing the system in a Phase II clinical trial.
Forty-five patients undergoing permanent Pd-103 seed implantation for prostate cancer were prospectively enrolled. Seed implantation was performed and dose was tracked intraoperatively using intraoperative registered ultrasound and fluoroscopy (iRUF). Three-dimensional seed locations were computed from X-rays and registered to ultrasound for intraoperative dosimetry, followed by adaptive plan modification to achieve prostate V100 ≥95% and ≥95% D90. Time required for iRUF was recorded. Postoperative CT/MRI scans were performed 1 day after the implantation and used as reference for dosimetric analysis. Dosimetric parameters for the prostate and urethra were compared between standard ultrasound-based dosimetry (USD), iRUF, and postoperative CT/MRI.
Mean total time for iRUF was <30 min. A mean of four seeds (0-12) were added per implant to correct cold spots discovered by iRUF. Day 1 CT/MRI prostate V100 was ≥95% for 44/45 patients; 1 patient had Day 1 V100 93%. No patient had rectal V100 exceeding 1 cc. Compared to CT/MRI, iRUF dosimetry had significantly smaller mean differences and higher correlations for all prostate and urethral dosimetric parameters examined than USD. Both USD and iRUF tended to overestimate dose, but with less bias in iRUF than USD.
Intraoperative dosimetry utilizing iRUF was associated with acceptable increase in procedure time and enabled very high rates of achieving excellent prostate dose coverage. iRUF intraoperative dosimetry approximated postoperative CT/MRI dosimetry to a greater degree than USD for the prostate and urethra.
评估术中剂量测定系统的性能，并获得在II期临床试验中使用该系统时所取得的剂量测定结果的估计值。
前瞻性纳入45例接受前列腺癌永久性钯-103粒子植入的患者。进行粒子植入，并使用术中配准超声和荧光透视（iRUF）在术中追踪剂量。根据X射线计算三维粒子位置，并将其与超声配准以进行术中剂量测定，随后进行适应性计划修改，以实现前列腺V100≥95%和D90≥95%。记录iRUF所需时间。植入后1天进行术后CT/MRI扫描，并用作剂量分析的参考。比较前列腺和尿道的剂量参数在基于标准超声的剂量测定（USD）、iRUF和术后CT/MRI之间的差异。
iRUF的平均总时间<30分钟。每次植入平均添加4粒（0-12粒）种子，以纠正iRUF发现的冷区。44/45例患者术后第1天CT/MRI前列腺V100≥95%；1例患者术后第1天V100为93%。没有患者的直肠V100超过1cc。与CT/MRI相比，对于所有检查的前列腺和尿道剂量参数，iRUF剂量测定的平均差异显著更小，相关性更高。USD和iRUF都倾向于高估剂量，但iRUF的偏差小于USD。
使用iRUF进行术中剂量测定与手术时间可接受的增加相关，并能实现非常高的前列腺剂量覆盖优良率。对于前列腺和尿道，iRUF术中剂量测定比USD在更大程度上接近术后CT/MRI剂量测定。
