Study On The Spatial Dose Distribution And Computer Simulation Of Multiple Palladium-103 Seed Sources

In today's society, the malignant tumor has become a serious threat to human health disease. On medicine the main methods of treating cancer are surgery, chemotherapy, radiotherapy methods and so on at present, and the development direction of modern medicine is the minimally invasive and the noninvasive treatment, precise therefore radiotherapy has become the main method of malignant tumor therapy. Brachytherapy is the floorboard of radiation treatments. The radionuclide is encapsulated in the seed source, and the seed source is placed in tumor body, near the tumor body, or the surface of tumor body for implementing illuminate. The dose distribution calculation is the brachytherapy plan design of base and core.According to the dose parameters and experimental data from the American Association of Physicists in Medicine (AAPM) TG-43 and TG-43U1 protocols, the brachytherapy dose calculation model of 103Pd seed source was studied in terms of theory.In this paper, Radial dose function in the dose calculation model of single 103Pd seed source was studied, and the mathematical model was established by the nonlinear theory. The model of radial dose function compared with other models, the calculation results are in good agreement with the experimental data.Based on the dose calculation model of single 103Pd seed source, the dose calculation model of multiple 103Pd seed sources was theoretically derived by using scalar superposition method. The theoretical calculation result and the clinical experiment results are basically the same. In addition, the above model has the flexibility and universal applicability. Changing the corresponding parameters can be used for the dose calculation of other different kinds and types of seed sources.The brachytherapy dose calculation software system of 103Pd seed source was developed based on the dose calculation model of 103Pd seed source. The system mainly consists of four interface, the main function includes:the decay activity calculation of the different kinds of nuclide after a period of time; the dose rate calculation of different kinds and types of seed sources in two-dimensional plane and three-dimensional space; the absorbed dose calculation of seed source after a period of time; drawing the isodose contour of seed source in two-dimensional plane and the isodose surface of seed source in three-dimensional space; saving all kinds of calculation results, photos and interfaces. Especially in the three-dimensional display of isodose surface, the software sets pop-up graphics display window function. The azimuth and elevation of isodose surface can be changed through the rotation, be convenient for the user to observe the isodose surface from different viewpoints. This system has friendly interface and easy operation, interactivity and compatibility are strong, operation speed is fast. This software system applied to clinical trial, and the results are in accordance with the results of clinical experiment. The software system can be further popularized.