Monte Carlo Simulation Of Pancreatic Cancer By Repetitive Structure Cards

Pancreatic cancer is an extremely common digestive malignant tumors. Despite its low incidence, accounting for 1 ~ 4% of all cancers, the incidence rate is close to death rate. In recent decades it has increased and become the 4th largest cancer death in the world. The current treatment methods include surgery, chemotherapy, radiotherapy. and nearly 70% patients need radiotherapy .In order to get the distribution of particles which are implantated into tumor ,we can use three-dimensional treatment planning system (TPS) .Because it can obtain the neutron energy spectrum, positioning, tumor and normal tissue dose distribution to optimize the configuration by irradiation process simulation. Because of three-dimensional geometry. MCNP have been used to develop treatment planning system.At present, only 125I particles has been used in clinical application in China. But 103Pb particles has been widely used overseas, and they got a good achievement. So, in this article, we use the structure cards to divide body into different unit and fill them with organizations replacement material and establish the precise model of geometry. Then implant each 125I, 103Pb radiation sources into geometry models,and simulate the distribution of photons. We find that no matter distance, the average dose rate of 125I particles to is higher than 103pd particles'and when the tumors is closer to radiation source, the difference between 125I and 103Pb is much larger. Secondly, the average dose rate of 125I and 103Pb source changes as the radius of tumors.