Radiographic image analyzing device, method, and recording medium

1. A radiographic image analyzing device for analyzing a subject image obtained by radiographic imaging of a subject to estimate a body thickness distribution of the subject, the device comprising:

an image obtaining unit for obtaining the subject image;

a body thickness distribution modifying unit for receiving input of a virtual model having an estimated body thickness distribution and modifying the estimated body thickness distribution of the virtual model to output the modified estimated body thickness distribution, the body thickness distribution modifying unit comprising:

a virtual model obtaining unit for obtaining the inputted virtual model having the estimated body thickness distribution,

an estimated image generating unit for generating an estimated image, which is an estimate of a radiographic image that would be obtained by radiographic imaging of the subject, by combining an estimated primary ray image, which is an estimate of a primary ray image that would be obtained by radiographic imaging of the obtained virtual model, and an estimated scattered ray image, which is an estimate of a scattered ray image that would be obtained by radiographic imaging of the virtual model, and

a modifying unit for modifying the obtained estimated body thickness distribution such that a difference between the estimated image and the subject image is reduced, and outputting the modified estimated body thickness distribution; and

a body thickness distribution determining unit for controlling execution of a body thickness distribution modifying process that causes the modifying unit to modify the estimated body thickness distribution of the virtual model and output the modified estimated body thickness distribution, causes the virtual model obtaining unit to obtain the virtual model having the outputted estimated body thickness distribution inputted thereto, and causes the estimated image generating unit to generate the estimated image from the virtual model, wherein the body thickness distribution modifying process is iteratively executed until a termination condition is satisfied, and, if the termination condition is satisfied, the body thickness distribution determining unit determines the estimated body thickness distribution that is outputted by the body thickness distribution modifying process when the termination condition is satisfied to be used as the body thickness distribution of the subject,

wherein the body thickness distribution determining unit comprises a judging unit for switching, according to a judgment condition, between a first control under which the body thickness distribution modifying process is iteratively executed until a first termination condition is satisfied and a second control under which the body thickness distribution modifying process is iteratively executed until a second termination condition that is different from the first termination condition is satisfied so that one of the first control and the second control is executed, the number of iterations of the body thickness distribution modifying process under the second control being smaller than the number of iterations of the body thickness distribution modifying process under the first control.

2. The radiographic image analyzing device as claimed in claim 1 , wherein the judging unit estimates an estimated run time, which is an estimate of a sum of run times of the body thickness distribution modifying process that is iteratively executed until the first termination condition is satisfied, based on time-series transition of the difference between the estimated image and the subject image during the iteratively executed body thickness distribution modifying process, and the judging unit executes the second control if the estimated run time is greater than a first time limit, and executes the first control if the estimated run time is not greater than the first time limit.

3. The radiographic image analyzing device as claimed in claim 1 , wherein, based on processing capacity information that indicates processing capacity of the radiographic image analyzing device, the judging unit executes the second control if the processing capacity is lower than a certain processing level, and executes the first control if the processing capacity is not lower than the certain processing level.

4. The radiographic image analyzing device as claimed in claim 3 , wherein the processing capacity information is information indicating the type of the imaging apparatus used to take the subject image.

5. The radiographic image analyzing device as claimed in claim 1 , wherein, based on associating information that associates each imaging location with the first control or the second control, the judging unit executes the first control if the imaging location of the subject image is associated with the first control, and executes the second control if the imaging location of the subject image is associated with the second control.

6. The radiographic image analyzing device as claimed in claim 1 , wherein, based on emergency display information that indicates whether or not emergency display of the subject image is necessary, the judging unit executes the second control if the emergency display is necessary, and executes the first control if the emergency display is not necessary.

7. The radiographic image analyzing device as claimed in claim 1 , wherein, based on associating information that associates each body part shown in the subject image with the first control or the second control, the judging unit executes the first control if the body part shown in the subject image is associated with the first control, and executes the second control if the body part shown in the subject image is associated with the second control.

8. The radiographic image analyzing device as claimed in claim 1 , wherein

the first termination condition represents a first threshold value which is an acceptable value of the difference between the estimated image generated by the estimated image generating unit and the subject image,

the second termination condition represents a second threshold value which is an acceptable value of the difference between the estimated image generated by the estimated image generating unit and the subject image, and

the second threshold value is greater than the first threshold value.

9. The radiographic image analyzing device as claimed in claim 1 , wherein the second termination condition represents an upper limit value of the number of iterations of the body thickness distribution modifying process, or an upper limit value of a sum of run times of the body thickness distribution modifying process.

10. The radiographic image analyzing device as claimed in claim 1 , further comprising:

an image processing unit for performing image processing on the subject image using a process parameter depending on the body thickness distribution of the subject to obtain a processed image, and

a display control unit for displaying the processed image on a display unit.

11. A radiographic image analyzing method to be executed by a radiographic image analyzing device for analyzing a subject image obtained by radiographic imaging of a subject to estimate a body thickness distribution of the subject, the method comprising:

an image obtaining step of obtaining the subject image;

a body thickness distribution modifying step of receiving input of a virtual model having an estimated body thickness distribution and modifying the estimated body thickness distribution of the virtual model to output the modified estimated body thickness distribution, the body thickness distribution modifying step comprising:

a virtual model obtaining step of obtaining the inputted virtual model having the estimated body thickness distribution,

an estimated image generating step of generating an estimated image, which is an estimate of a radiographic image that would be obtained by radiographic imaging of the subject, by combining an estimated primary ray image, which is an estimate of a primary ray image that would be obtained by radiographic imaging of the obtained virtual model, and an estimated scattered ray image, which is an estimate of a scattered ray image that would be obtained by radiographic imaging of the virtual model, and

a modifying step of modifying the obtained estimated body thickness distribution such that a difference between the estimated image and the subject image is reduced, and outputting the modified estimated body thickness distribution; and

a body thickness distribution determining step of controlling execution of a body thickness distribution modifying process that causes the estimated body thickness distribution of the virtual model to be modified and the modified estimated body thickness distribution to be outputted in the modifying step, causes the virtual model having the outputted estimated body thickness distribution to be obtained in the virtual model obtaining step, and causes the estimated image to be generated from the virtual model in the estimated image generating step, wherein the body thickness distribution modifying process is iteratively executed until a termination condition is satisfied, and, if the termination condition is satisfied, the estimated body thickness distribution that is outputted by the body thickness distribution modifying process when the termination condition is satisfied is determined to be used as the body thickness distribution of the subject,

wherein the body thickness distribution determining step comprises a judging step of switching, according to a judgment condition, between a first control under which the body thickness distribution modifying process is iteratively executed until a first termination condition is satisfied and a second control under which the body thickness distribution modifying process is iteratively executed until a second termination condition that is different from the first termination condition is satisfied so that one of the first control and the second control is executed, the number of iterations of the body thickness distribution modifying process under the second control being smaller than the number of iterations of the body thickness distribution modifying process under the first control.

12. A non-transitory computer-readable recording medium containing a radiographic image analyzing program for analyzing a subject image obtained by radiographic imaging of a subject to estimate a body thickness distribution of the subject, the program causing a computer to function as:

an image obtaining unit for obtaining the subject image;

a body thickness distribution modifying unit for receiving input of a virtual model having an estimated body thickness distribution and modifying the estimated body thickness distribution of the virtual model to output the modified estimated body thickness distribution, the body thickness distribution modifying unit comprising:

a virtual model obtaining unit for obtaining the inputted virtual model having the estimated body thickness distribution,

an estimated image generating unit for generating an estimated image, which is an estimate of a radiographic image that would be obtained by radiographic imaging of the subject, by combining an estimated primary ray image, which is an estimate of a primary ray image that would be obtained by radiographic imaging of the obtained virtual model, and an estimated scattered ray image, which is an estimate of a scattered ray image that would be obtained by radiographic imaging of the virtual model, and

a modifying unit for modifying the obtained estimated body thickness distribution such that a difference between the estimated image and the subject image is reduced, and outputting the modified estimated body thickness distribution; and

a body thickness distribution determining unit for controlling execution of a body thickness distribution modifying process that causes the modifying unit to modify the estimated body thickness distribution of the virtual model and output the modified estimated body thickness distribution, causes the virtual model obtaining unit to obtain the virtual model having the outputted estimated body thickness distribution inputted thereto, and causes the estimated image generating unit to generate the estimated image from the virtual model, wherein the body thickness distribution modifying process is iteratively executed until a termination condition is satisfied, and, if the termination condition is satisfied, the body thickness distribution determining unit determines the estimated body thickness distribution that is outputted by the body thickness distribution modifying process when the termination condition is satisfied to be used as the body thickness distribution of the subject,

wherein the body thickness distribution determining unit comprises a judging unit for switching, according to a judgment condition, between a first control under which the body thickness distribution modifying process is iteratively executed until a first termination condition is satisfied and a second control under which the body thickness distribution modifying process is iteratively executed until a second termination condition that is different from the first termination condition is satisfied so that one of the first control and the second control is executed, the number of iterations of the body thickness distribution modifying process under the second control being smaller than the number of iterations of the body thickness distribution modifying process under the first control.