Physics Analysis Of Intensity Modulated Radiotherapy Treatment Planning System

As time goes by, more and more great developments of physics achieved as the other sciences, physics has a great progress, there are many other related theory and science are based on physics and the development, the technology and methods of physics research and practice in all walks of life is also more and more extensive and in-depth applications, which is an important research direction and the combination of clinical medicine. Each new discovery of physics or physical technology development to a new stage, for medical research and clinical medical treatment provides a more advanced, more convenient and more sophisticated instruments and methods. In physics based on the development and production of linear accelerator is very important in current clinical medicine a treatment system, treatment planning system is also associated with use of the research and development of the knowledge of physics.As the development of physics, the radiation therapy is becoming a more important technology in the clinical departments. This study using four different treatment-planning-systems(Monaco2.02,Corvus08,Xio4.0,Pinnacle9.2h)for esophageal cancer intensity-modulated radiation treatment planning design,analyze and compare the dose distribution and calculation accuracy. During the treatment two different measurement methods for set-up error were compared. To investigate the effect of several parameter settings for esophageal cancer intensity-modulated radiation treatment.Analysis of results: These four TPSs PTV CI had comparable and no differences. In Corvus plans, the homogenous dose distribution was poor. In these plans, the lung received the higher dose, but the protection of the spinal cord was better, and treatment time is relatively long. In Monaco plans, high-dose region of GTV is larger, 95%, 99% and 100% PTV volume received the lower dose. In Pinnacle plans, PTV had smaller high-dose region and showed a very good dose distribution, and the lung tissue of V5 received the lower dose. Analysis of Monte Carlo results: Esophageal PTV dose and volume parameters between the four planning system, there was no significant difference. Lung V20 received the higher dose in Corvus plans, while the protection of the spinal cord was good.The setup errors of esophageal carcinoma patients measured by EPID were-1.18/4.19 mm in X direction,-1.3/4.47 mm in Y direction,1.41/4.81 mm in Z direction. The setup errors of esophageal carcinoma patients measured by CBCT were-0.5/4.5 mm in X direction,4.1/7.0 mm in Y direction,-1.1/3.3 mm in Z direction.For the point dose verification,the pass ratio of plans measured by ionization chamber were within-3.9%~+4.8%;For the data which were measured and analyzed using Matrixx and Delt4 evaluated by Gamma index,the pass ratio of plans within 3%/3mm criteria were higher than 95% and have excellent agreement to meet clinical requirements.