Irradiation planning apparatus and irradiation plan correction method

Abstract

Provided is an irradiation planning apparatus including: a three-dimensional CT value data acquisition unit (); a prescription data input processing unit () which acquires prescription data; a stopping power ratio conversion unit () and a nuclear reaction effective density conversion unit () which respectively generate first conversion data () and second conversion data () on the basis of three-dimensional CT value data; and a calculation unit () which calculates a dose distribution on the basis of the prescription data, the first conversion data (), and the second conversion data (), wherein the stopping power ratio conversion unit () and the nuclear reaction effective density conversion unit () perform correction processing for correcting data obtained from the three-dimensional CT value data, using a physical quantity indicative of a likelihood of spalling particles of incident charged particle beam (), and then determine the dose distribution. Thus, in calculation of a dose distribution in a body in particle beam irradiation planning, a dose error introduced by a difference between the probability of nuclear reaction initiated, in a body, by incident particles and the probability of nuclear reaction initiated, in water, by incident particles is simply and accurately corrected.