Radiation image processing device, radiation image processing method, and radiation image processing program
A processor acquires two radiation images having a contrast based on a first characteristic related to a first imaging apparatus, derives a body thickness distribution of a subject based on at least one of the two radiation images, removes a scattered ray component from the two radiation images based on the first characteristic, derives a first bone part image and a first soft part image representing a bone tissue and a soft tissue of the subject, respectively, from the two radiation images, converts the first bone part image and the first soft part image into a second bone part image and a second soft part image having a contrast based on a second characteristic related to a second imaging apparatus, based on the first characteristic, the second characteristic, and the body thickness distribution, and derives a processed radiation image having the contrast based on the second characteristic by adding the second bone part image and the second soft part image.
1 . A radiation image processing device comprising:
at least one processor,
wherein the processor
acquires two radiation images having a contrast based on a first characteristic related to a first imaging apparatus, the two radiation images being acquired by imaging a subject including a soft part and a bone part with the first imaging apparatus using radiation having different energy distributions,
derives a body thickness distribution of the subject based on at least one of the two radiation images,
removes a scattered ray component, which is included in radiation transmitted through the subject and is scattered by the subject, from the two radiation images based on the first characteristic,
derives a first bone part image representing a bone tissue of the subject and a first soft part image representing a soft tissue of the subject by performing weighting subtraction on the two radiation images from which the scattered ray component is removed,
converts the first bone part image and the first soft part image into a second bone part image and a second soft part image having a contrast based on a second characteristic related to a second imaging apparatus different from the first imaging apparatus, by calculating a correction factor based on a radiation attenuation coefficient included in the first characteristic, a radiation attenuation coefficient included in the second characteristic, and the body thickness distribution, and performing a calculation in which the correction factor is multiplied, for each pixel, by the first bone part image and the first soft part image, and
derives a processed radiation image having the contrast based on the second characteristic by adding all corresponding pixels of the second bone part image and the second soft part image.
2 . The radiation image processing device according to claim 1 ,
wherein the processor
derives a scattered ray component in accordance with the second characteristic based on the second characteristic and the body thickness distribution, and
further derives the processed radiation image by using the derived scattered ray component.
3 . The radiation image processing device according to claim 1 ,
wherein the first characteristic includes energy of the radiation used in the first imaging apparatus, a radiation attenuation coefficient in accordance with the body thickness distribution for an object interposed between the subject and a radiation detector that detects the radiation transmitted through the subject in the first imaging apparatus, a ratio of the scattered ray component included in the radiation transmitted through the subject in accordance with the body thickness distribution, and a point spread function in accordance with the body thickness distribution, and
the second characteristic includes energy of the radiation used in the second imaging apparatus, a radiation attenuation coefficient in accordance with the body thickness distribution for an object interposed between the subject and a radiation detector that detects the radiation transmitted through the subject in the second imaging apparatus, a ratio of the scattered ray component included in the radiation transmitted through the subject in accordance with the body thickness distribution, and a point spread function in accordance with the body thickness distribution.
4 . The radiation image processing device according to claim 1 ,
wherein the processor displays the processed radiation image and a radiation image of the subject acquired by the second imaging apparatus.
5 . A radiation image processing method comprising:
acquiring two radiation images having a contrast based on a first characteristic related to a first imaging apparatus, the two radiation images being acquired by imaging a subject including a soft part and a bone part with the first imaging apparatus using radiation having different energy distributions;
deriving a body thickness distribution of the subject based on at least one of the two radiation images;
removing a scattered ray component, which is included in radiation transmitted through the subject and is scattered by the subject, from the two radiation images based on the first characteristic;
deriving a first bone part image representing a bone tissue of the subject and a first soft part image representing a soft tissue of the subject by performing weighting subtraction on the two radiation images from which the scattered ray component is removed;
converting the first bone part image and the first soft part image into a second bone part image and a second soft part image having a contrast based on a second characteristic related to a second imaging apparatus different from the first imaging apparatus, by calculating a correction factor based on a radiation attenuation coefficient included in the first characteristic, a radiation attenuation coefficient included in the second characteristic, and the body thickness distribution, and performing a calculation in which the correction factor is multiplied, for each pixel, by the first bone part image and the first soft part image; and
deriving a processed radiation image having the contrast based on the second characteristic by adding all corresponding pixels of the second bone part image and the second soft part image.
6 . A non-transitory computer-readable storage medium that stores radiation image processing program causing a computer to execute:
a procedure of acquiring two radiation images having a contrast based on a first characteristic related to a first imaging apparatus, the two radiation images being acquired by imaging a subject including a soft part and a bone part with the first imaging apparatus using radiation having different energy distributions;
a procedure of deriving a body thickness distribution of the subject based on at least one of the two radiation images;
a procedure of removing a scattered ray component, which is included in radiation transmitted through the subject and is scattered by the subject, from the two radiation images based on the first characteristic;
a procedure of deriving a first bone part image representing a bone tissue of the subject and a first soft part image representing a soft tissue of the subject by performing weighting subtraction on the two radiation images from which the scattered ray component is removed;
a procedure of converting the first bone part image and the first soft part image into a second bone part image and a second soft part image having a contrast based on a second characteristic related to a second imaging apparatus different from the first imaging apparatus, by calculating a correction factor based on a radiation attenuation coefficient included in the first characteristic, a radiation attenuation coefficient included in the second characteristic, and the body thickness distribution, and performing a calculation in which the correction factor is multiplied, for each pixel, by the first bone part image and the first soft part image; and
a procedure of deriving a processed radiation image having the contrast based on the second characteristic by adding all corresponding pixels of the second bone part image and the second soft part image.