Development of a treatment planning protocol for prostate treatments using intensity modulated radiotherapy
نویسندگان
چکیده
We have developed a treatment planning protocol for intensity-modulated radiation therapy of the prostate using commercially available inverse planning software. Treatment plans were developed for ten patients using the Corvus version 3.8 planning system, testing various prescription options, including tissue types, dose volume histogram values for the target and normal structures, beam arrangements, and number of intensity levels. All plans were scaled so that 95% of the clinical target volume received 75.6 Gy; mean doses to the prostate were typically 79 Gy. The reproducibility of the inverse planning algorithm was tested by repeating a set of the plans five times. Plans were deemed acceptable if they satisfied predefined dose constraints for the targets and critical organs. Figures of merit for target coverage, target dose uniformity, and organ sparing were used to rank acceptable plans. Certain systematic behaviors of the optimizer were noted: the high dose regions for both targets and critical organs were 5-10 Gy more than prescribed; reducing bladder and rectum tolerance increased the range of doses within the target; increasing the number of fields incrementally improved plan quality. A set of planning parameters was found that usually satisfied the minimum requirements. Repeating the optimization with different beam order produced similar but slightly different dose distributions, which was sometimes useful for finding acceptable solutions for difficult cases. The standard set of parameters serves as a useful starting point for individualized planning.
منابع مشابه
3-Dimensional conformal radiotherapy versus intensity modulated radiotherapy for localized prostate cancer: Dosimetric and radiobiologic analysis
Background: To analyze the dosimetric and radio biologic advantages between intensity modulated radiotherapy (IMRT) and 3 dimensional conformal radiotherapy (3DCRT) and selection of optimal photon energy for IMRT treatments. Material and methods: 24 patients with localized prostate carcinoma were planned for 3DCRT and IMRT techniques. Radiation dose of 54 Gy with 2 Gy/fraction, was planned to ...
متن کاملDosimetric Evaluation of Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiotherapy (IMRT) Using AAPM TG 119 Protocol
Background: The commissioning accuracy of Volumetric Modulated Arc Therapy (VMAT) need to be evaluated.Objective: To test and evaluate commissioning accuracy of VMAT based on the TG 119 protocols at local institution. Material and Methods: The phantom, structure sets, VMAT and IMRT beam parameter setup, dose prescriptions and planning objectives were following TG 119 guidelines to c...
متن کاملMonte Carlo Simulation of Prostate Intensity Modulated Radiotherapy Using PRIMO Software: A Feasibility Study
Introduction: Nowadays Intensity Modulated Radiotherapy (IMRT) is a common method for treating prostate cancers. Must of the Monte Carlo software cannot simulate the IMRT procedures due to inability of these soft wares to simulate the multi leaf collimator (MLC) positions or movements. A new user-friendly software based on the PENELOPE Monte Carlo code named PRIMO was published...
متن کاملEvaluation of treatment planning system monitor unit calculations for three intensity modulated radiotherapy delivery techniques
Background: We have validated the monitor unit calculations from a commercially available treatment planning system (TPS) for three intensity modulated radiotherapy (IMRT) planning techniques for tangential breast irradiation by using ionization chamber measurements. Materials and Methods: Treatment plans were generated for forty-two breast patients by a forward planned field in field ...
متن کاملAssessment and Comparison of Homogeneity and Conformity Indexes in Step-and-Shoot, Compensator-Based Intensity Modulated Radiation Therapy (IMRT) and Three-Dimensional Conformal Radiation Therapy (3D CRT) in Prostate Cancer
Introduction: Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) are two treatment modalities in prostate cancer, which provide acceptable dose distribution in tumor region with sparing the surrounding normal tissues. IMRT is based on inverse planning optimization; in which, intensity of beams is modified by using multileaf c...
متن کامل