  Objective: Mapping of transrectal ultrasonographic (TRUS) prostate biopsies
is of fundamental importance for either diagnostic purposes or the management
and treatment of prostate cancer, but the localization of the cores seems
inaccurate. Our objective was to evaluate the capacities of an operator to plan
transrectal prostate biopsies under 2-dimensional TRUS guidance using a
registration algorithm to represent the localization of biopsies in a reference
3-dimensional ultrasonographic volume.
  Methods: Thirty-two patients underwent a series of 12 prostate biopsies under
local anesthesia performed by 1 operator using a TRUS probe combined with
specific third-party software to verify that the biopsies were indeed conducted
within the planned targets. RESULTS: The operator reached 71% of the planned
targets with substantial variability that depended on their localization (100%
success rate for targets in the middle and right parasagittal parts versus 53%
for targets in the left lateral base). Feedback from this system after each
series of biopsies enabled the operator to significantly improve his dexterity
over the course of time (first 16 patients: median score, 7 of 10 and cumulated
median biopsy length in targets of 90 mm; last 16 patients, median score, 9 of
10 and a cumulated median length of 121 mm; P = .046).
  Conclusions: In addition to being a useful tool to improve the distribution
of prostate biopsies, the potential of this system is above all the preparation
of a detailed "map" of each patient showing biopsy zones without substantial
changes in routine clinical practices.
