MP35-01 BASELINE PREVALENCE AND MAGNITUDE OF SPATIAL DEVIATIONS IN A SIMULATOR FROM THE TRANSRECTAL ULTRASOUND PROSTATE BIOPSY TEMPLATE

Abstract

INTRODUCTION AND OBJECTIVES: During templated transrectal ultrasound prostate biopsy (TRUS PBx), the closer the actual PBx samples match a desired template (resulting in uniform spatial distribution of samples including regions where PCa is likely) the higher the probability of sampling PCa and avoiding a false negative. A mental model for templated PBx is a set of 12 circles (2D representation of spheres construed as the recommended centers for the cylindrical biopsy cores) evenly distributed on a posterior-anterior view of the prostate. We set out to quantify the baseline (first attempt at sampling a 12-core set) prevalence and magnitude of deviation from the 12-circle template during simulated TRUS PBx by trainees and experienced urologic practitioners. METHOD(S): With IRB approval, 15 participants (12 residents, 3 faculty) performed a 12-core templated TRUS PBx using a mixed reality simulator: tracked TRUS probe (BK 8818), side-firing needle guide, tracked needle gun (Bard Max-Core MC1825). We measured the spatial deviation (mm) of the actual core center from each of the 12 templated centers for each study participant. The centers of the 12 target spheres are set in a plane parallel to, and 7 mm away, from the rectal surface of the prostate. RESULT(S): Baseline deviations (averaged over 12 cores) ranged from 6.5 to 24.5 mm (Table). Two-thirds (10/15) of urologist participants achieved a baseline error (averaged over 12 cores) of 11 mm or less. The distribution of urologists for different error thresholds (mm) was: