Ultrasonically guided transperineal seed implantation of the prostate: modification of the technique and qualitative assessment of implants.

During the period 1988-1991, 23 patients with prostatic carcinoma were treated by transperineal iodine seed implantation guided by transrectal ultrasound. We introduce a refinement of the implantation technique using a rigid column of seeds and spacers. The uniformity parameter based on the peak width of the natural volume-dose histogram demonstrated quantitatively that this refinement resulted in a more accurate seed arrangement.