Medical image processing apparatus and medical image processing method
There are provided a medical image processing apparatus and a medical image processing method making it possible to reduce metal artifacts with no loss of a detailed structure in a metallic region. The medical image processing apparatus is configured to reconstruct a tomographic image from projection data of a subject in which metal material is included and includes a projection space correction section which corrects the projection data and thereby generates corrected projection data, an image space correction section which corrects the tomographic image by using the corrected projection data, and a coefficient setting section which sets a projection space coefficient which is used in the projection space correction section and an image space coefficient which is used in the image space correction section.
1. A medical image processing apparatus which reconstructs a tomographic image from projection data of a subject in which metal material is included, comprising:
a projection space correction section which corrects the projection data and thereby generates corrected projection data;
an image space correction section which corrects the tomographic image by using the corrected projection data; and
a coefficient setting section which sets a projection space coefficient which is used in the projection space correction section and an image space coefficient which is used in the image space correction section,
wherein the larger the projection space coefficient is, the smaller the image space coefficient becomes.
2. The medical image processing apparatus according to claim 1 , wherein the coefficient setting section sets the projection space coefficient and the image space coefficient on the basis of any of a feature value of a metallic region, a scanning condition used when acquiring the projection data, and a reconstruction condition used when reconstructing the tomographic image.
3. The medical image processing apparatus according to claim 2 ,
wherein the feature value includes any of a maximum pixel value, an area, and roundness of the metallic region in the tomographic image, and
the coefficient setting section sets the projection space coefficient larger and sets the image space coefficient smaller as the feature value becomes larger.
4. The medical image processing apparatus according to claim 3 , wherein the feature value is obtained by using a metal image which is generated by extracting the metallic region from within the tomographic image.
5. A medical image processing apparatus which reconstructs a tomographic image from projection data of a subject in which metal material is included, comprising:
a projection space correction section which corrects the projection data and thereby generates corrected projection data;
an image space correction section which corrects the tomographic image by using the corrected projection data; and
a coefficient setting section which sets a projection space coefficient which is used in the projection space correction section and an image space coefficient which is used in the image space correction section;
wherein the coefficient setting section sets the projection space coefficient and the image space coefficient on the basis of any of a feature value of a metallic region, a scanning condition used when acquiring the projection data, and a reconstruction condition used when reconstructing the tomographic image,
wherein the scanning condition includes a cone angle which is an opening angle in a body axis direction of the subject, and
the coefficient setting section sets the projection space coefficient larger and sets the image space coefficient smaller as the cone angle of the projection data becomes smaller.
6. A medical image processing apparatus which reconstructs a tomographic image from projection data of a subject in which metal material is included, comprising:
a projection space correction section which corrects the projection data and thereby generates corrected projection data;
an image space correction section which corrects the tomographic image by using the corrected projection data; and
a coefficient setting section which sets a projection space coefficient which is used in the projection space correction section and an image space coefficient which is used in the image space correction section;
wherein the coefficient setting section sets the projection space coefficient and the image space coefficient on the basis of any of a feature value of a metallic region, a scanning condition used when acquiring the projection data, and a reconstruction condition used when reconstructing the tomographic image, and
wherein the coefficient setting section sets the projection space coefficient larger and sets the image space coefficient smaller as body motion of the subject becomes smaller.
7. The medical image processing apparatus according to claim 6 , wherein in a case where it is specified that a scanned region is the heart or the chest from the scanning condition and the reconstruction condition, it is decided that the body motion of the subject is large.
8. The medical image processing apparatus according to claim 6 , wherein the body motion of the subject is obtained on the basis of a differential value between counter projection data which is opposed to the projection data and the projection data.
9. A medical image processing method for reconstructing a tomographic image from projection data of a subject in which metal material is included, comprising:
a projection space correcting step of correcting the projection data and thereby generating corrected projection data;
an image space correcting step of correcting the tomographic image by using the corrected projection data; and
a coefficient setting step of setting a projection space coefficient which is used in the projection space correcting step and an image space coefficient which is used in the image space correcting step,
wherein the larger the projection space coefficient is, the smaller the image space coefficient becomes.