PROBLEM TO BE SOLVED: To estimate, in an image analysis apparatus, method, and program, a subjects body thickness distribution by analyzing an image of the subject taken by irradiating the subject with radiation.SOLUTION: The method comprises: obtaining a subjects image obtaining model information in which a models image photographed by irradiating the model with radiation is associated with the models body thickness distribution in the models image for each of multiple models that are different from the subject obtaining characteristic information that indicates the characteristics of the subjects image obtaining each characteristic information that indicates the characteristics of the multiple model images on the basis of the multiple model information identifying the models image having characteristic information that is similar to the characteristic information of the subjects image and determining the body thickness distribution associated with the identified model image as the body thickness distribution of the subjects image.SELECTED DRAWING: Figure 1
