Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran , nickfarjam6262@gmail.com
Abstract: (16 Views)
Background:Advances in radiotherapy techniques have enabled the possibility of more accurate dose delivery to the Planning Target Volume (PTV) and limiting dose to Organs At Risk (OARs). The present study aimed to evaluate and compare dosimetric parameters using the Anisotropic Analytical Algorithm (AAA) in the Eclipse Treatment Planning System (TPS) between 3-Dimensional Conformal Radiotherapy (3D-CRT) and Intensity-Modulated Radiotherapy (IMRT) techniques for prostate cancer patients. Materials and Methods: 3D-CRT and sliding window IMRT plans were produced for 100 prostate cancer patients before prostatectomy in the Eclipse TPS. The dose coverage of PTV, volume-dose constraints for OARs, conformity, and homogeneity indices were assessed from the dose-volume histogram (DVH). Dosimetric parameters were compared by Statistical Analysis Software. Results: The maximum dose delivered to PTV was a higher value with sliding window IMRT than 3D-CRT (p-value<0.001). Based on the ability to perform tumor dose escalation in IMRT plans, this technique provided higher values of Dmean, D98%, D95%, D50% and D2% than 3D-CRT. Volume-dose parameters (V15, V25, V35 and V50) for the rectum, bladder, and femoral heads were significantly reduced in IMRT technique. Compared with 3D-CRT, dose distributions of IMRT plans were less homogeneous. The conformity index was obtained better for IMRT plans(p-value<0.001). Conclusion: IMRT plans significantly improved dosimetric values of PTV and resulted in better target coverage and inhomogeneity of dose distributions as well as led to decreased volumes irradiation of critical organs than 3D-CRT plans. Therefore, IMRT technique is recommended as the first choice to improve treatment planning for prostate cancer patients.