Purpose: To compare the dose coverage, conformity, and homogeneity between high-dose-rate (HDR) brachytherapy and permanent prostate implant (PPI) in the treatment of prostate adenocarcinoma.
Methods and materials: From January 2003 to August 2004, 54 patients (108 implants) underwent HDR brachytherapy of prostate cancer with iridium-192 stepping source. Of patients who underwent PPI brachytherapy with iodine-125, 72 patients were randomly selected for the purpose of dosimetric comparison. PPI preplan was done based on transrectal ultrasound study, and postplan was done using CT 1 month after implant. Dosimetric parameters of HDR were compared to that of PPI preplan and postplan.
Results: HDR brachytherapy had lower D90 (111.5% vs. 120.2%), lower V100 (97.2% vs. 99.6%), lower natural dose ratio (1.03 vs. 1.13), higher conformal index (0.69 vs. 0.62), and higher homogeneity index (0.63 vs. 0.52) than PPI preplan (all p < 0.0001). All the dosimetric parameters of PPI postplan including D90 (86.7%), V100 (82.0%), natural dose ratio (0.92), conformal index (0.53), and homogeneity index (0.42) were inferior to HDR brachytherapy (all p < 0.0001).
Conclusions: HDR brachytherapy of the prostate can provide better dose coverage, conformity, and homogeneity compared to PPI.