Comparison of intraoperatively built custom linked seeds versus loose seed gun applicator technique using real-time intraoperative planning for permanent prostate brachytherapy.

Abstract

To report our dosimetric results using a novel push-button seed delivery system that constructs custom links of seeds intraoperatively. From 2005 to 2007, 43 patients underwent implantation using a gun applicator (GA), and from 2007 to 2008, 48 patients underwent implantation with a novel technique allowing creation of intraoperatively built custom links of seeds (IBCL). Specific endpoint analyses were prostate D90% (pD90%), rV100% > 1.3 cc, and overall time under anesthesia. Final analyses included 91 patients, 43 GA and 48 IBCL. Absolute change in pD90% (ΔpD90%) between intraoperative and postoperative plans was evaluated. Using GA method, the ΔpD90% was -8.1 Gy and -12.8 Gy for I-125 and Pd-103 implants, respectively. Similarly, the IBCL technique resulted in a ΔpD90% of -8.7 Gy and -9.8 Gy for I-125 and Pd-103 implants, respectively. No statistically significant difference in ΔpD90% was found comparing methods. The GA method had two intraoperative and 10 postoperative rV100% >1.3 cc. For IBCL, five intraoperative and eight postoperative plans had rV100% >1.3 cc. For GA, the mean time under anesthesia was 75 min and 87 min for Pd-103 and I-125 implants, respectively. For IBCL, the mean time was 86 and 98 min for Pd-103 and I-125. There was a statistical difference between the methods when comparing mean time under anesthesia. Dosimetrically relevant endpoints were equivalent between the two methods. Currently, time under anesthesia is longer using the IBCL technique but has decreased over time. IBCL is a straightforward brachytherapy technique that can be implemented into clinical practice as an alternative to gun applicators.