Tomographic image generation method and radiographic imaging apparatus

1. A tomographic image generation method comprising:

acquiring a plurality of projection images including microstructure information by irradiating a subject with radiation at a plurality of different angles and detecting the radiation transmitted through the subject;

acquiring a first tomographic image including the microstructure information and first artifact information by directly reconstructing the plurality of projection images;

performing first blurring processing on each of the plurality of projection images to maintain a high-contrast region and blur a region other than the high-contrast region;

acquiring a second tomographic image including second artifact information by reconstructing the plurality of projection images that have undergone the first blurring processing; and

acquiring a subtraction tomographic image by subtracting the second tomographic image from the first tomographic image.

2. The tomographic image generation method according to claim 1 , wherein the second tomographic image is subtracted from the first tomographic image to acquire the subtraction tomographic image including a difference between the first artifact information and the second artifact information and the microstructure information.

3. The tomographic image generation method according to claim 2 , wherein

each of the plurality of projection images undergoes second blurring processing to apply blurring throughout the projection image;

the plurality of projection images that have undergone the second blurring processing are reconstructed to acquire a third tomographic image; and

the third tomographic image is added to the subtraction tomographic image to acquire an addition tomographic image.

4. The tomographic image generation method according to claim 3 , wherein the addition tomographic image is acquired by subtracting second luminance value information included in the second tomographic image from first luminance value information included in the first tomographic image and adding third luminance value information included in the third tomographic image.

5. The tomographic image generation method according to claim 1 , wherein in the first blurring processing, a region having a higher contrast than the microstructure information is maintained as the high-contrast region, and a region other than the region having the higher contrast than the microstructure information is blurred.

6. A radiographic imaging apparatus comprising:

an imager configured to irradiate a subject with radiation at a plurality of different angles, to detect the radiation transmitted through the subject, and to capture a plurality of projection images including microstructure information; and

an image processor configured to process the plurality of projection images captured by the imager; wherein

the image processor is configured to acquire a first tomographic image including the microstructure information and first artifact information by directly reconstructing the plurality of projection images, to perform first blurring processing on each of the plurality of projection images so as to maintain a high-contrast region and blur a region other than the high-contrast region, to acquire a second tomographic image including second artifact information by reconstructing the plurality of projection images that have undergone the first blurring processing, and to acquire a subtraction tomographic image by subtracting the second tomographic image from the first tomographic image.

7. The radiographic imaging apparatus according to claim 6 , wherein the subtraction tomographic image includes a difference between the first artifact information and the second artifact information and the microstructure information.

8. The radiographic imaging apparatus according to claim 7 , wherein the image processor is configured to perform second blurring processing on each of the plurality of projection images so as to apply blurring throughout the projection image, to acquire a third tomographic image by reconstructing the plurality of projection images that have undergone the second blurring processing, and to acquire an addition tomographic image by adding the third tomographic image to the subtraction tomographic image.