Abstract
Prostate cancer is one of the most common cancers in men. The purpose of this work is to compare between intensity-modulated radiotherapy (IMRT) versus three-dimensional conformal radiotherapy (3D-CRT) planning in patients with prostate cancer using 6-MV and 15-MV photon energies. Twenty patients with localized prostate cancer were planned on Xio treatment planning system. Four treatment plans were generated for each patient. IMRT whether 6 or 15 MV beam was slightly better in terms of target coverage, but not significant (p 0.05) in comparison to 3D-CRT in both beam energies. IMRT was better than 3D-CRT in terms of organs at risk (OARs) sparing and conformity index (CI) in both 6 and 15-MV whereas 3D-CRT in both 6 and 15-MV yielded better homogeneity index (HI) compared to IMRT 6 and 15-MV. The number of monitor units (MU) increased in IMRT compared to 3D-CRT. Also, MU increased in low energy compared to high energy whether in 3D-CRT or IMRT (p<0.05). When IMRT 6-MV and IMRT 15-MV were compared, no significant difference was found in terms of target coverage and OARs except the rectum which was better in IMRT 6-MV compared to IMRT 15-MV. IMRT 6-MV technique should be prioritized when user has options for treatment and then 3D-CRT as a second line when the former is not available. The choice of the energies (6 and 15MV) used with 3D-CRT depends largely on patient's body geometry, while the use of a high energy IMRT 15-MV is not recommended.