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456Medicine, Tatsuo Ouchi, Hiromoto Takahashi, and Toshio Wagai of Juntendo University developed and clinically applied transrectal prostate ultra-sound (Figure 6).Analysis of prostate cancer localization toward improved diagnostic accuracy of transperineal prostate biopsy3). Delineating the precise localiza-tion of prostate cancer is important in improving the diagnostic accuracy of prostate biopsy. In Juntendo University Nerima Hospital, initial 12- core or repeat 16-core biopsies were performed using a transrectal ultrasound guided transperineal prostate biopsy method. We step-sectioned pros-tates from radical prostatectomy specimens at 5-mm intervals from the urethra to the urinary bladder and designated five regions: the (1) Apex, (2) Apex-Mid, (3) Mid, (4) Mid-Base, and (5) Base. We then mapped prostate cancer localization on eight zones around the urethra for each of those regions. Prostate cancer was detected in 93 cases of 121 cases (76.9%) in the Apex, in 115 cases (95.0%) in the Apex-Mid, in 101 cases (83.5%) in the Mid, in 71 cases (58.7%) in the Mid-Base, and in 23 cases (19.0%) in the Base. In 99.2% of all cases, prostate cancers were detected from the Apex to Mid regions. For this reason, transperineal prostate biopsies have routinely been prioritized in the Apex, Apex-Mid, and Mid regions, while the Base region of the prostate was considered to be of lesser importance. Our analyses of prostate cancer Figure 6　Transrectal prostate ultrasoundlocalization revealed a higher rate of cancer in the posterior portion of the Apex, antero-medial and postero-medial portion of the Apex-Mid and ante-ro-medial and postero-lateral portion of the Mid. The transperineal prostate biopsies in our institute performed had a sensitivity of 70.9%, a specificity of 96.6%, a positive predictive value (PPV) of 92.2% and a negative predictive value (NPV) of 85.5% (Figure 7, 8, Table 1, 2).The concordance of prostate cancer between prostatectomy specimens and biopsies is compara-tively favorable. According to our study, the diag-nostic accuracy of transperineal prostate biopsy Figure 7　Transperineal prostate biopsy : transverse view, lateral view, and front viewConclusions