Purpose:To investigate the dosimetric and radiobiological differences among volumetric modulated arc therapy(VMAT),high-dose-rate(HDR)brachytherapy,and low-dose-rate(LDR)permanent seeds implant for localized prostate cancer.Methods and Materials:Ten patients with localized prostate cancer were selected for this study.VMAT,HDR brachytherapy and LDR permanent seeds implant plans were created for each patient.For VMAT,planning target volume(PTV)was defined as the clinical target volume plus a margin of 5 mm.Rectum,bladder,urethra and femoral heads were considered as organs at risk.78 Gy in 39 fractions were prescribed for PTV.For HDR and LDR plans,the dose prescription was D90 of 34 Gy in 8.5 Gy per fraction,and 145 Gy to clinical target volume,respectively.The dose and dose volume parameters were evaluated for target,organs at risk and normal tissue.Physical dose were converted to dose based on 2-Gy fractions(equivalent dose in 2 Gy per fraction,EQD2)for comparison of three techniques.Results:HDR and LDR significantly reduced the dose to rectum and bladder compared with VMAT.The Dmean(EQD2)of rectum decreased 22.36 Gy in HDR and 17.01 Gy in LDR from 30.24 Gy in VMAT,respectively.The Dmean(EQD2)of bladder decreased 6.91 Gy in HDR and 2.53 Gy in LDR from 13.46 Gy in VMAT.For the femoral heads and normal tissue,the mean doses were also significantly reduced in both HDR and LDR compared with VMAT.For the urethra,the mean dose was 80.26 Gy,70.23 Gy and 104.91 Gy in VMAT,HDR and LDR brachytherapy,respectively.Conclusion:For localized prostate cancer,both HDR and LDR brachytherapy were clearly superior in the sparing of rectum,bladder,femoral heads and normal tissue compared with VMAT.HDR provided the advantage in sparing of urethra compared with VMAT and LDR.