Re-implantation following suboptimal dosimetry in low-dose-rate prostate brachytherapy: technique for outpatient source insertion using local anesthesia

Abstract

Objective The objective of this study is to describe our method and results for improvement of suboptimal initial postimplant dosimetry using targeted seed placement under local anesthesia within a clinic setting. Methods Re-implantation was performed in an outpatient clinic using local anesthesia with transrectal ultrasound (TRUS) and template-guided insertion of additional seeds in a shielded suite without general anesthesia. Patient reported discomfort is minimal, and time to complete the procedure is 30 min or less. D90 and V100 were used to measure implantation quality in both the initial and re-implantation setting. Results Ten patients were treated from October 2010 to December 2012 with additional Pd-103 seeds to improve initial post-implant dosimetry. A median of 73 seeds were placed initially (range 55-113), and a median of 3 additional seeds added later (range 2-6). Re-implantation was performed a median of 31 days after initial implantation (range 12-70). Median initial D90 was 100.2 % and initial V100 was 90.1 %. The median increase in D90 was 25.7 % (range 10.2-44.4 %), and the corresponding V100 increased by a median of 6.6 % (range 3.3-14.2 %). Median urethral D30 increased by 4.1 % (range 0.9-25 %) and rectal V100 increased by a median of 0.01 cm 3 (range 0-0.75 cm 3 ). A potential operating room cost reduction of $4000-$7000 and additional savings from general anesthesia fees is possible. Conclusions Re-implantation under local anesthesia for LDR prostate brachytherapy improves suboptimal dosimetry and avoids the risk and cost of OR/anesthesia time.