Radiation therapy planning system, radiation therapy planning method, and radiation therapy system

A radiation therapy planning method, using a simplified Monte Carlo algorithm for calculating a dose to be assigned to particles by referring to an integrated dose distribution table, comprising:

• inputting a target region and a prescription dose of an irradiated body which is to be irradiated with radiation;
• storing, in a memory, a radiation decreasing rate table indicating a relationship between a track length of the radiation to the irradiated body and a decreasing rate of the radiation;
• calculating dose distribution by using the simplified Monte Carlo algorithm based on the target region and the prescription dose of the irradiated body and correcting the calculated dose distribution by using the decreasing rate of the radiation of the radiation decreasing rate table stored in the memory;
• and
• storing the calculated dose distribution in the memory.

A radiation therapy system, using a simplified Monte Carlo algorithm for calculating a dose to be assigned to particles by referring to an integrated dose distribution table, comprising:

• a radiation therapy apparatus that irradiates a target region of an irradiated body with radiation according to a dose distribution;
• and
• a radiation therapy planning apparatus that calculates irradiation dose distribution of the radiation in the radiation therapy apparatus, and performs planning of a radiation therapy,
• wherein the radiation therapy planning apparatus includes,
• an input device to input a target region and a prescription dose of an irradiated body which is to be irradiated with radiation;
• a memory storing a radiation decreasing rate table indicating a relationship between a track length of the radiation to the irradiated body and a decreasing rate of the radiation;
• and
• a processor coupled with the input device and the memory that is configured to calculate dose distribution by using the simplified Monte Carlo algorithm based on the target region and the prescription dose of the irradiated body and correct the calculated dose distribution by using the decreasing rate of the radiation of the radiation decreasing rate table stored in the memory,
• wherein the radiation therapy planning apparatus transmits the calculated dose distribution to the radiation therapy apparatus.