Program Information
Reducing Seed Waste and Increasing Value of Dynamic Intraoperative Implantation of Pd-103 Seeds in Prostate Brachytherapy
P Taylor*1, AC Riegel 1 2, (1) Department of Radiation Medicine, Northwell Health System, Center For Advanced Medicine, Lake Success, NY 11042 (2) Hofstra Northwell School of Medicine, Hempstead, NY 11042
Presentations
SA-B-BRA|B-12 (Saturday, March 18, 2017) 10:30 AM - 12:30 PM Room: Ballroom A|B
Purpose: Several nomograms exist for ordering ¹⁰³Pd seeds for dynamic intraoperative prostate seed implants (PSI). Excess seeds from prostate brachytherapy pose additional radiation safety risks and increase the cost of care. This study compared five nomograms to clinical PSI data to determine (1) the cause of excess seeds and (2) the optimal nomogram for our institution.
Methods: Pre-operative and intra-operative clinical data were collected for monotherapy PSI with ¹⁰³Pd. Dosimetric evaluation was performed with 3-D transrectal ultrasound and a DVH of the prostate and OARs. The number of implanted seeds was normalized for each patient such that pre-op volume=intra-op volume, the number of ordered seeds matched the in-house nomogram, D90%=100%, and air kerma strength=2U. The normalized number of implanted seeds was plotted against intra-operative prostate volume and compared to four previously published nomograms and an in-house nomogram.
Results: Of the n=220 total cases, 97.8% had excess seeds. On average, 25.5%±10.0% of ordered seeds were wasted. Excess seeds which could not be attributed to one of the normalization parameters were considered “unaccounted-for-excess.” The total number of seeds that could be attributed to the normalization parameters, were subtracted from the number of excess seeds to determine the number of unaccounted for excess seeds. Any of these normalization parameters had the potential to contribute to or reduce the number of unaccounted-for-excess seeds. On average, 30.7%±7.1% of the normalized number of excess seeds were unaccounted for. The upper 99.9% C.I. of our clinical data plus a 5% “buffer” may provide a more reasonable ¹⁰³Pd seed ordering nomogram for our institution.
Conclusion: By comparing clinical data spanning six years (2010-2015) and 220 patients, we found substantial disparity between published nomograms. Reducing excess seeds will reduce exposure to patients and staff, and reduce cost, which may increase the value of PSI compared with other treatment modalities.
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