Dosimetric Analysis of Three Different Sets of Five Fields and Seven Fields IMRT Plans for Prostate Cancer: Comparative Study

The advent of Intensity Modulated Radiation Therapy (IMRT) is rapidly changing the field of Radiation
Oncology. IMRT has the potential to improve clinical implementation of highly conformal non-convex
dose distributions. The ability of IMRT to reduce dose to nearby normal structures without sacrificing
dose coverage of the target makes it an ideal treatment modality for prostate cancer. Nonetheless, a
number of IMRT approaches including coplanar and noncop-lanar beam techniques with 5 to 9
beams at different angles have been used in an effort to get the best dose distribution. The purpose
of this study is to compare the dose to normal tissue and dose-limiting structures, conformity index,
homogeneity index, number of monitor units required for the treatment of prostate cancer in 3 sets of
five and seven beam IMRT plans and thus to select the best IMRT approach for patients with prostate
cancer.