Study On The Dose Distribution Of Medical Linear Accelerator Therapeutic Room Based On Monte Carlo

With more and more patients with tumor, each big hospital to increase investment in the treatment of tumors, especially radiotherapy equipment, a variety of high quality medical electron accelerator models continue to emerge, medical accelerator has become radiation therapy in the field of mainstream radio therapy instrument.In radiotherapy, in order to ensure the quality of radiotherapy and radiation shielding effect, the need for dose distribution and radiation therapy in the body of the indoor radiation dose distribution was calculated accurately.This research uses the Monte Carlo method, with the help of the MCNP program of the accelerators in radiotherapy dose distribution was studied.(1) Detailed model of the accelerator head structure is established.(2) By using the step-by-step simulation method, to get the spectral energy distribution and angular distribution of X ray flux produced by the electronic target,then the X-ray as a source to calculate the beam therapy in water model in three-dimensional dose distribution, and the percent depth dose and off-axis ratio curve and the measured values were compared. Results showed that the two meet very well and that the accelerator head model and physical process is accurate.(3) Accelerator head and room model is established according to the actual room parameters, draw the accelerator in energy 10 MV, shooting wild 10 x 10cm2 setting under four different directions the X-ray dose in the treatment chamber in various regions of the distribution map, also calculate photoneutrons in the center of the 2m range of dose levels, analysts pointed out that treatment chamber X-ray dose attenuation trend ratio with the square of the distance is inversely proportional to the attenuation trend to slow and after a transition radiation levels decreased by an order of magnitude, shielding optimization design provides the direction(4)In the treatment chamber of the selected ten points were measured, the measured and calculated comparison showed that only a few errors, the overall good agreement with the numerical calculation of the dose within the room is accurate and reliable, the calculated values can represent the actual level of radiation.I hope the data and conclusions for the future related shielding design and optimization of dose evaluation for reference, the work can help to study on the accelerator for radiation protection, lay the foundation for further research in the future.