Radiographic image analysis device and method, and storage medium having stored therein program

A radiographic image analysis method that is performed in a radiographic image analysis device and analyzes a subject image which is obtained by irradiating a subject with radiation to estimate a body thickness distribution of the subject, the method comprising:

• an image acquisition step of acquiring the subject image;
• a virtual model acquisition step of acquiring a virtual model of the subject having a predetermined body thickness distribution;
• an estimated image generation step of generating a composite image of an estimated primary X-ray image, which is obtained by estimating a primary X-ray image of the virtual model obtained by radiography from the virtual model, and an estimated scattered X-ray image, which is obtained by estimating a scattered X-ray image of the virtual model obtained by radiography from the virtual model, as an estimated image which is obtained by estimating a radiographic image of the subject obtained by radiography;
• a correction step of correcting the body thickness distribution of the virtual model such that a difference between the estimated image and the subject image is reduced;
• a body thickness distribution determination step of determining the corrected body thickness distribution of the virtual model as the body thickness distribution of the subject;
• a scattered X-ray information acquisition step of acquiring scattered X-ray information which is obtained by estimating a scattered X-ray of the subject image, using the determined body thickness distribution of the subject;
• a characteristic acquisition step of acquiring a first virtual grid characteristic which is a characteristic of a virtual scattered X-ray removal grid;
• and
• a scattered X-ray removal step of performing a process of removing the scattered X-ray of the subject image on the basis of the scattered X-ray information and the first virtual grid characteristic that have been acquired.

A non-transitory computer-readable storage medium having stored therein a radiographic image analysis program that analyzes a subject image which is obtained by irradiating a subject with radiation to estimate a body thickness distribution of the subject, the program causing a computer to perform:

• an image acquisition step of acquiring the subject image;
• a virtual model acquisition step of acquiring a virtual model of the subject having a predetermined body thickness distribution;
• an estimated image generation step of generating a composite image of an estimated primary X-ray image, which is obtained by estimating a primary X-ray image of the virtual model obtained by radiography from the virtual model, and an estimated scattered X-ray image, which is obtained by estimating a scattered X-ray image of the virtual model obtained by radiography from the virtual model, as an estimated image which is obtained by estimating a radiographic image of the subject obtained by radiography;
• a correction step of correcting the body thickness distribution of the virtual model such that a difference between the estimated image and the subject image is reduced;
• a body thickness distribution determination step of determining the corrected body thickness distribution of the virtual model as the body thickness distribution of the subject;
• a scattered X-ray information acquisition step of acquiring scattered X-ray information which is obtained by estimating a scattered X-ray of the subject image, using the determined body thickness distribution of the subject;
• a characteristic acquisition step of acquiring a first virtual grid characteristic which is a characteristic of a virtual scattered X-ray removal grid;
• and
• a scattered X-ray removal step of performing a process of removing the scattered X-ray of the subject image on the basis of the scattered X-ray information and the first virtual grid characteristic that have been acquired.