JP6814008B2 - Radiation tomography equipment and its control program - Google Patents

Description

The present invention relates to a radiation tomography apparatus and a control program thereof for irradiating an imaged object with radiation to acquire projection data and performing image reconstruction processing on the projection data to create a reconstructed image.

The radiography apparatus that creates a reconstructed image based on the projection data obtained by the radiation scan of the imaged object performs the image reconstructing process on the projected data according to the required reconstructing conditions to create the reconstructed image. By changing the reconstruction conditions, it is possible to obtain reconstructed images having different image quality, such as a reconstructed image having a high resolution and a reconstructed image in which image noise is reduced. The image quality of the reconstructed image also changes depending on the radiation dose.

In the radiography apparatus, a plurality of reconstruction conditions may be selectable (see, for example, Patent Document 1). The user selects an image reconstruction condition capable of obtaining a reconstruction image having a desired image quality from the viewpoint of resolution, image noise, and the like. In addition, the radiation dose can also be set by the user.

Japanese Unexamined Patent Publication No. 2013-192827

For example, when a user wants to perform radiography at a predetermined dose, the obtained reconstructed image may not have a desired amount of image noise regardless of which of a plurality of image reconstructing conditions is selected. On the other hand, there is a limit to setting the image reconstruction conditions that can obtain the desired image quality at the dose desired by the user, and setting many expected image reconstruction conditions also leads to an increase in the cost of the device. .. Therefore, there is a demand for a radiographic apparatus and a control program thereof that can increase the degree of freedom of combination of radiation dose, image reconstruction conditions, and image noise amount by the user when creating a reconstructed image.

The invention of one viewpoint made to solve the above-mentioned problems is based on a scanning device that irradiates an imaged object with radiation to scan, and a first image based on the projected data obtained by the scanning. The image reconstruction process is performed by the first reconstruction image creation unit that performs the image reconstruction processing according to the reconstruction condition to create the first reconstruction image, and the second image reconstruction condition based on the projection data. A third reconstructed image is created by adding a second reconstructed image creating unit that creates a second reconstructed image in a row, the first reconstructed image, and the second reconstructed image. 3 Reconstructed image creation unit and an input device that accepts input by an operator, and the input is input of the dose of the radiation and the amount of image noise in the third reconstructed image, or the input of the radiation. The input includes the dose, the amount of image noise in the third reconstructed image, and at least one of the first image reconstructed condition and the second image reconstructed condition, or the first image reconstructed. An input device that is an input including a condition, the second image reconstruction condition, a dose of the radiation, and at least one of the image noise amount in the third reconstruction image, the radiation dose, and the image noise amount. , The addition ratio is specified based on the storage device that stores the relationship between the first reconstructed image and the addition ratio of the second reconstructed image, and the input received by the input device and the relationship. The third reconstructed image creating unit includes a specific unit, and the third reconstructed image creating unit is a radiation tomography apparatus characterized in that the third reconstructed image is created at the addition ratio specified by the specific unit. ..

According to the invention of the above viewpoint, the relationship between the radiation dose, the image noise amount, and the addition ratio of the first reconstructed image and the second reconstructed image is stored in the storage device. Based on the input received by the input device and the relationship, the addition ratio of the first reconstructed image and the second reconstructed image is specified, and the third reconstructed image is created. As a result, it is possible to increase the degree of freedom for the user to combine the radiation dose, the image reconstruction condition, and the amount of image noise when creating the reconstructed image.

It is a figure which shows schematic the hardware structure of the X-ray CT apparatus which concerns on embodiment. It is a functional block diagram of the operation console of the X-ray CT apparatus shown in FIG. It is a conceptual diagram explaining the creation of the 1st reconstruction image, the 2nd reconstruction image and the 3rd reconstruction image. It is a figure which shows an example of a table. It is explanatory drawing which shows the plurality of image reconstruction functions in relation to the spatial resolution and the amount of image noise. It is a figure which shows the user interface which sets the image noise amount. It is a figure which shows the state which the slider in the user interface is slid.

Hereinafter, embodiments of the present invention will be described. FIG. 1 shows an X-ray CT apparatus 1 which is an example of an embodiment of the radiation tomography apparatus according to the present invention. As shown in FIG. 1, the X-ray CT apparatus 1 includes a gantry 2, an imaging table 4, and an operation console (console) 6.

The gantry 2 includes an X-ray tube 21, an aperture 22, a collimator device 23, an X-ray detector 24, a data collection unit 25, a rotating unit 26, a high voltage power supply 27, an aperture driving device 28, and a rotary drive. It has a device 29 and a gantry table control unit 30.

The X-ray tube 21 and the X-ray detector 24 are arranged so as to face each other with the opening 2B interposed therebetween. While the X-ray tube 21 and the X-ray detector 24 rotate with the rotation of the rotating unit 26, X-rays are emitted from the X-ray tube 21 to the imaging target 5 to perform scanning. The X-ray tube 21 and the X-ray detector 24 are examples of embodiments of the scanning device in the present invention.

The aperture 22 is arranged between the X-ray tube 21 and the opening 2B. The X-rays emitted from the X-ray focal point of the X-ray tube 21 toward the X-ray detector 24 are formed into a fan beam or a cone beam.

The collimator device 23 is arranged between the opening 2B and the X-ray detector 24. The collimator device 23 removes scattered rays incident on the X-ray detector 24.

The X-ray detector 24 is a plurality of two-dimensionally arranged X-ray detectors 24 in a spreading direction (referred to as a channel) and a thickness direction (referred to as a column direction) of a fan-shaped X-ray beam emitted from an X-ray tube 21. It has an X-ray detection element. Each X-ray detection element detects the transmitted X-rays of the imaging target 5 arranged in the opening 2B, and outputs an electric signal according to the intensity thereof. The imaging target 5 is, for example, a living body such as a human or an animal.

The data collection unit 25 receives the electric signal output from each X-ray detection element of the X-ray detector 24, converts it into X-ray data, and collects it. This X-ray data is referred to as projection data.

The rotating portion 26 is rotatably supported around the opening 2B. The rotating unit 26 is equipped with an X-ray tube 21, an aperture 22, a collimator device 23, an X-ray detector 24, and a data collecting unit 25.

The photographing table 4 has a cradle 41 and a cradle driving device 42. The photographing object 5 is placed on the cradle 41. The cradle driving device 42 puts the cradle 41 in and out of the opening 2B of the gantry 2, that is, the photographing space.

The high voltage power supply 27 supplies a high voltage and a current to the X-ray tube 21.

The aperture drive device 28 drives the aperture 22 to deform its opening.

The rotation drive device 29 rotationally drives the rotation unit 26.

The gantry table control unit 30 controls each device / unit in the gantry 2, the photographing table 4, and the like.

The operation console 6 receives various operations from the operator. The operation console 6 has an input device 61, a display device 62, a storage device 63, and an arithmetic processing device 64. In this example, the operation console 6 is composed of a computer.

The input device 61 includes a button and a keyboard (keyboard) for receiving instructions and information input from the operator, and further includes a pointing device and the like. The display device 62 is an LCD (Liquid Crystal Display), an organic EL (Electro-Luminescence) display, or the like. The input device 61 is an example of an embodiment of the input device in the present invention.

The storage device 63 includes an HDD (Hard Disk Drive), a semiconductor memory (Memory) such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and the like. The operation console 6 may have all of the HDD, RAM, and ROM as the storage device 63.

The arithmetic processing device 64 is a processor such as a CPU (central processing unit).

An external storage medium 90 may be connected to the operation console 6. The external storage medium 90 is a non-transient storage medium having portability such as a CD (Compact Disk), a DVD (Digital Versaille Disk), a USB (Universal Serial Bus) memory, and a hard disk.

The storage device 63 and the external storage medium 90 are examples of embodiments of the storage device in the present invention.

Here, as shown in FIG. 1, the body axis direction of the imaging target 5, that is, the transport direction of the imaging target 5 by the imaging table 4 is defined as the z direction. Further, the vertical direction is defined as the y direction, and the horizontal direction orthogonal to the y direction and the z direction is defined as the x direction.

As shown in FIG. 2, the operation console 6 has a scan control unit 71, a first reconstructed image creating unit 72, a second reconstructed image creating unit 73, and a third reconstructed image creating unit 74 as functional blocks. , A specific unit 75 and a display control unit 76. The arithmetic processing device 64 uses the above-mentioned scan control unit 71, the first reconstructed image creating unit 72, the second reconstructed image creating unit 73, and the third reconstructed image creating unit 74 by a predetermined program (program). , The functions of the specific unit 75 and the display control unit 76 are executed. The predetermined program is stored in a non-transient storage medium such as an HDD or a ROM constituting the storage device 63, for example. Further, the program may be stored in the externally connected non-transient external storage medium 90.

The scan control unit 71 controls the gantry table control unit 30 so that scanning is performed for a required range in the body axis direction (z direction) of the imaging target 5 according to the operation of the operator.

The first reconstructed image creating unit 72 creates a first reconstructed image by performing an image reconstructing process according to the first image reconstructing condition based on the projection data obtained by the X-ray scan. .. The first reconstructed image creating unit 72 is an example of the embodiment of the first reconstructed image creating unit in the present invention.

Based on the projection data, the second reconstructed image creation unit 73 performs an image reconstructing process under a second image reconstructing condition different from the first image reconstructing condition to obtain a second reconstructed image. create. The second reconstructed image creating unit 73 is an example of the embodiment of the second reconstructed image creating unit in the present invention.

The third reconstructed image creation unit 74 creates a third reconstructed image by adding the first reconstructed image and the second reconstructed image. The third reconstructed image creating unit 74 is an example of the embodiment of the third reconstructed image creating unit in the present invention.

The identification unit 75 specifies, for example, the addition ratio of the first reconstructed image and the second reconstructed image. Details will be described later. The specific part 75 is an example of the embodiment of the specific part in the present invention.

The display control unit 76 controls the display device 62 so as to display various images and texts on the screen.

Next, the processing in the X-ray CT apparatus 1 according to the present embodiment will be described. In the X-ray CT apparatus 1, the X-ray tube 21 and the X-ray detector 24 rotate around the body axis of the subject to scan X-rays and collect projection data. The projection data is collected for at least the number of views required for image reconstruction (projection data of a plurality of views corresponding to 180 ° + fan angle α or 360 °).

When the projection data is collected, the image reconstruction processing is performed on the projection data after performing a predetermined preprocessing. The image reconstruction process will be specifically described. As shown in FIG. 3, the first reconstructed image creating unit 72 creates the data of the first reconstructed image Im1 by performing the image reconstructing process on the projection data PD according to the first image reconstructing condition. To do. The first image reconstruction condition is the first image reconstruction function. Further, the second reconstructed image creating unit 73 creates the data of the second reconstructed image Im2 by performing the image reconstructing process on the projection data PD according to the second image reconstructing condition. The second image reconstruction condition is the second image reconstruction function.

As shown in FIG. 3, the third reconstruction image creating unit 74 adds the data of the first reconstruction image Im1 and the data of the second reconstruction image Im2 at a predetermined ratio to perform the third reconstruction. Create data for image Im3. In FIG. 3, the data of the third reconstructed image Im3 is created by the following (Equation 1). However, (Equation 1) is an example.
Im3 = Im1 × α + Im2 × (1-α) ・ ・ ・ (Equation 1)
In (Equation 1), 0 <α <1.

The display control unit 76 may display the third reconstructed image Im3 on the display device 63.

The third reconstructed image creating unit 74 creates the third reconstructed image Im3 after the specific unit 75 specifies the addition ratio of the first reconstructed image Im1 and the second reconstructed image Im2. .. The identification of the addition ratio will be described. The timing at which the addition ratio is specified is, for example, when the X-ray CT apparatus 1 is installed in a facility such as a hospital or immediately before the actual imaging is performed. The storage device 63 stores the relationship between the X-ray dose, the amount of image noise, and the addition ratio of the first reconstructed image Im1 and the second reconstructed image Im2. This relationship may be stored in the external storage medium 90. The identification unit 75 specifies the addition ratio based on the stored relationship and the user's input received by the input device 61. The identification unit 75 receives an input received by the input device 61 among the X-ray dose, the amount of image noise, the first image reconstruction function, and the second image reconstruction function that the input device does not accept. Further specifying based on the above relationship with the above, and specifying the addition ratio.

The relationship will be described. The relationship is, for example, a table TA that defines the relationship between the addition ratio determined according to the dose of X-rays and the amount of image noise. For example, as shown in FIG. 4, a plurality of table TAs may be stored depending on the dose of X-rays. In FIG. 4, four tables TA1, TA2, TA3, and TA4 are shown as the plurality of tables TA. However, these tables TA1 to TA4 are examples, and tables different from these or more than four tables may be stored.

Here, the tables TA1 to TA4 according to the X-ray doses D1 and D2 are shown. In the tables TA1 to TA4, the first reconstructed image created by the first image reconstructing function and the second reconstructed image created by the second image reconstructing function according to the X-ray doses D1 and D2. The amount of image noise corresponding to the addition ratio with the reconstructed image is defined. In each of the tables TA1 to TA4, the addition ratio of the first reconstructed image created by the first image reconstruction function is shown in the upper row, and the second image reconstructed function created by the second image reconstruction function is shown in the middle row. The addition ratio of the reconstructed image is shown, and the amount of image noise is shown in the lower row.

The tables TA1 to TA4 will be described in more detail. The X-ray doses D1 and D2 are, for example, absorbed doses and CTDI values. Tables TA1 to TA4 are tables in which at least one of the first image reconstruction function for creating the first reconstruction image and the second image reconstruction function for creating the second reconstruction image is different from the other tables. Includes. Specifically, in the tables TA1 and TA3, the first image reconstruction function is the function Kernel1, and the second image reconstruction function is the function Kernel2. Further, in the tables TA2 and TA4, the first image reconstruction function is the function Kernel2, and the second image reconstruction function is the function Kernel3.

The first image reconstruction function and the second image reconstruction function included in the table TA are any one of a plurality of image reconstruction functions stored in advance in the storage device 63 or the external storage medium 90. These image reconstruction functions are used in the conventional image reconstruction processing, and are, for example, a plurality of image reconstruction functions from Kernel-1 to Kernel-n, as shown in FIG. In FIG. 5, the left side has a low spatial resolution and a small amount of image noise in the reconstructed image, and the right side has a high spatial resolution and a large amount of image noise in the reconstructed image.

In each of the tables TA1 to TA4, a plurality of addition ratios are defined. In each of the tables TA1 to TA4, the addition ratio is shown as a percentage (%), and the amount of image noise for each 10% is defined from 10% to 90%. Therefore, in the above-mentioned (Equation 1), 0.1 ≦ α ≦ 0.9.

The image noise amount in the tables TA1 to TA4 is the image noise amount in the third reconstructed image, and is, for example, the standard deviation (SD) of the CT value in the third reconstructed image.

In order to specify the addition ratio, the user inputs in the input device 61. The input received from the user by the input device 61 will be described. For example, the user inputs an X-ray dose at the input device 61. Based on the input X-ray dose, the display control unit 76 responds to an image corresponding to a normal image reconstruction function preset separately from the first image reconstruction function and the second image reconstruction function. The amount of noise is specified and displayed on the display device 62. As shown in FIG. 6, the display control unit 76 may display the user interface UI indicating the specified image noise amount on the display device 62. This user interface UI includes a bar B and a slider S that indicates the identified image noise amount in the bar B. On the bar B, a scale of 1 is displayed as the amount of image noise from the standard deviation of the CT value of 10 to 20. Here, the slider S is at the position of "10" on the bar B, and indicates that the standard deviation of the CT value specified as the amount of image noise is 10.

The user can set a desired amount of image noise using the displayed user interface UI. The desired amount of image noise is the amount of image noise in the third reconstructed image. Specifically, the input device 61 accepts an input by the user to slide the slider S. The input for sliding the slider S is an example of the embodiment of the image noise amount input in the present invention. The user uses the input device 61 to slide the slider S to the position of the desired image noise amount on the bar B.

When the input device 61 receives the input for sliding the slider S, the specific unit 75 uses the table TA from the image noise amount according to the position of the slider S and the X-ray dose input as described above. The addition ratio of the first reconstructed image and the second reconstructed image is specified. The specific unit 75 is created from the table TA by the first image reconstruction function, the second image reconstruction function, and the first image reconstruction function corresponding to the input image noise amount and the X-ray dose. The addition ratio of the first reconstructed image and the second reconstructed image created by the second image reconstructing function is specified. When at least one of the input image noise amount and the X-ray dose is not present in the table TA, the identification unit 75 specifies, for example, the image noise amount and the X-ray dose having the closest values in the table TA, and first. The image reconstruction function, the second image reconstruction function, and the addition ratio of the above may be specified.

The first reconstructed image creating unit 72 creates the data of the first reconstructed image Im1 by using the first image reconstructing function specified by the specific unit 75. Further, the second reconstructed image creating unit 73 creates the data of the second reconstructed image Im2 by using the second image reconstructing function specified by the specific unit 75. Then, the third reconstructed image creating unit 74 weights and adds the data of the first reconstructed image Im1 and the data of the second reconstructed image Im2 at the addition ratio specified by the specific unit 75, and the third The data of the reconstructed image Im3 of 3 is created. The third reconstructed image Im3 is an image noise amount input by the user or an image noise amount close to it.

According to the X-ray CT apparatus 1 of this example described above, when the user inputs the X-ray dose and the amount of image noise, the reconstructed image is not created by the stored image reconstruction function. The first reconstructed image Im1 and the second reconstructed image Im2 are added to create a third reconstructed image Im3. Therefore, it is possible to obtain a third reconstructed image Im3, which is a desired amount of image noise, at a dose of X-rays desired by the user.

Further, since the reconstructed image is not created by the stored image reconstructing function, the X-ray dose in creating the third reconstructed image, the first image reconstructing function, and the second It is possible to increase the degree of freedom of user combination of the image reconstruction function and the amount of image noise.

Although the present invention has been described above with reference to the above-described embodiment, it goes without saying that the present invention can be modified in various ways without changing the gist thereof. For example, the input items by the user for specifying the addition ratio are not limited to those described in the above embodiment. For example, the user may input the X-ray dose and the amount of image noise in the third reconstructed image, and at least one of the first image reconstructed function and the second image reconstructed function may be input. In this case, the identification unit 75 identifies an image reconstruction function that has not been input among the first image reconstruction function and the second image reconstruction function based on the input items and the table TA. Further specify the addition ratio. Further, the user may input the first image reconstruction function and the second image reconstruction function, and at least one of the X-ray dose and the image noise amount in the third reconstruction image may be input. In this case, the specifying unit 75 identifies which of the X-ray dose and the image noise amount is not input based on the input item and the table TA, and further specifies the addition ratio.

Further, in the storage device 63 or the external storage medium 90, instead of the table TA, a table that defines the relationship between the addition ratio and the X-ray dose, which is determined according to the amount of image noise in the third reconstructed image, is stored. It may have been done. In this case, a plurality of tables may be stored according to the amount of image noise.

Further, in the storage device 63 or the external storage medium 90, instead of the above table, a transfer function that inputs the X-ray dose and the amount of image noise in the third reconstructed image and outputs the addition ratio is stored. It may have been done. The transfer function is a function that can specify the first image reconstruction function and the second image reconstruction function in addition to the addition ratio based on the input. The first image reconstruction function and the second image reconstruction function are also the storage device 63 and the external storage medium 90, similarly to the first image reconstruction function and the second image reconstruction function in the above table TA. It may be any one of a plurality of image reconstruction functions stored in advance in. When the input device 61 receives the input of the X-ray dose and the amount of image noise by the user, the identification unit 75 specifies the first image reconstruction function and the second image reconstruction function by the transfer function, and the addition ratio. To identify.

Further, the first reconstructed image creating unit 72 and the second reconstructed image creating unit 73 may perform the image reconstructing process by the successive approximation method instead of the image reconstructing process using the image reconstructing function. .. In this case, the first image reconstruction condition is the first convergence condition in the successive approximation method, and the second image reconstruction condition is the second convergence condition in the successive approximation method. Therefore, in the above table and transfer function, the first convergence condition and the second convergence condition are used instead of the first image reconstruction function and the second image reconstruction function.

Further, a program for making a computer function as each means for performing control and processing in the X-ray CT apparatus is also an example of an embodiment of the invention.

1 X-ray CT device 3 Central processing unit 21 X-ray tube 24 X-ray detector 61 Input device 63 Storage device 72 First reconstructed image creation unit 73 Second reconstructed image creation unit 74 Third reconstructed image creation Part 75 Specific part 90 External storage medium

Claims (13)

A scanning device that irradiates the object to be photographed and scans it,
Based on the projection data obtained by the scan, the first reconstructed image creating unit that creates the first reconstructed image by performing the image reconstructing process according to the first image reconstructing condition.
A second reconstructed image creation unit that creates a second reconstructed image by performing an image reconstructed process according to the second image reconstructed condition based on the projection data.
A third reconstructed image creating unit that creates a third reconstructed image by adding the first reconstructed image and the second reconstructed image.
An input device that accepts input from the operator, the input being an input of the radiation dose and the amount of image noise in the third reconstructed image, or the radiation dose and the third reconstructed image. Is an input including the amount of image noise in the above and at least one of the first image reconstruction condition and the second image reconstruction condition, or the first image reconstruction condition and the second image reconstruction condition. An input device that is an input that includes conditions and at least one of the radiation dose and the amount of image noise in the third reconstructed image.
A storage device that stores the relationship between the radiation dose, the image noise amount, the addition ratio of the first reconstructed image and the second reconstructed image, and the like.
A specific unit that specifies the addition ratio based on the input received by the input device and the relationship.
With
The third reconstructed image creating unit is a radiation tomography apparatus characterized in that the third reconstructed image is created at the addition ratio specified by the specific unit. The addition ratio in the relationship stored in the storage device is different from the first reconstructed image created by each of the different first image reconstruction conditions and a plurality of different second image reconstructions. It is an addition ratio of the second reconstructed image created by each of the constituent conditions.
The specific unit accepts the radiation dose, the image noise amount, the first image reconstruction condition, and the second image reconstruction condition that the input device does not accept. The radiation tomography apparatus according to claim 1, wherein the addition ratio is specified by further specifying based on the input and the relationship. The specific unit has the first image reconstruction condition and the second image reconstruction condition based on the radiation dose received by the input device and the input of the image noise amount in the third reconstruction image and the relationship. The radiation tomography apparatus according to claim 2, wherein the image reconstruction condition is further specified to specify the addition ratio . The radiation fault according to any one of claims 1 to 3, wherein the first image reconstruction condition is the first image reconstruction function, and the second image reconstruction condition is the second image reconstruction function. Shooting device. The first image reconstruction condition is the first convergence condition in the successive approximation method, and the second image reconstruction condition is the second convergence condition in the successive approximation method. The radiation tomography apparatus according to any one item. The radiation tomography apparatus according to any one of claims 1 to 5, wherein the relationship is a table that defines the relationship between the addition ratio determined according to the dose of radiation and the amount of image noise. .. The radiation tomography apparatus according to any one of claims 1 to 5, wherein the relationship is a table that defines the relationship between the addition ratio determined according to the amount of image noise and the radiation dose. .. The radiation tomography apparatus according to claim 6 or 7, wherein the table includes a plurality of addition ratios. As the table, a plurality of tables are stored in the storage device, and the plurality of tables are different from the other tables in at least one of the first image reconstruction condition and the second image reconstruction condition. The radiation tomography apparatus according to any one of claims 6 to 8, wherein the radiation tomography apparatus includes a table. The radiation tomography apparatus according to any one of claims 1 to 5, wherein the relationship is a transfer function in which the dose of radiation and the amount of image noise are input and the addition ratio is output. .. Any of claims 1 to 10, wherein the first image reconstruction condition and the second image reconstruction condition are any one of a plurality of image reconstruction conditions stored in the storage device. The radiation tomography apparatus according to item 1. A scanning device that irradiates the object to be photographed and scans it,
An input device that accepts input by the operator and
With storage devices
With the processor
It is characterized by having
The processor may be programmed
A first reconstructed image creation function that creates a first reconstructed image by performing an image reconstructed process according to the first image reconstructed condition based on the projection data obtained by the scan.
A second reconstructed image creation function that creates a second reconstructed image by performing an image reconstructed process according to the second image reconstructed condition based on the projection data.
A third reconstructed image creation function that creates a third reconstructed image by adding the first reconstructed image and the second reconstructed image, and
With specific functions
Is characterized by the execution of
The input received by the input device is an input of the radiation dose and the image noise amount in the third reconstructed image, or the radiation dose and the image noise amount in the third reconstructed image, and the said. An input that includes at least one of the first image reconstruction condition and the second image reconstruction condition, or the first image reconstruction condition, the second image reconstruction condition, and the dose of the radiation. And an input including at least one of the image noise amounts in the third reconstructed image.
The storage device stores the relationship between the radiation dose, the image noise amount, and the addition ratio of the first reconstructed image and the second reconstructed image.
The specific function specifies the addition ratio based on the input received by the input device and the relationship.
The radiation tomography apparatus characterized in that the third reconstructed image creating function is for creating the third reconstructed image at the addition ratio specified by the specific unit. A scanning device that irradiates the object to be photographed and scans it,
An input device that accepts input by the operator and
With storage devices
With the processor
It is a control program of a radiation tomography apparatus characterized by being equipped with
To the processor
A first reconstructed image creation function that creates a first reconstructed image by performing an image reconstructed process according to the first image reconstructed condition based on the projection data obtained by the scan.
A second reconstructed image creation function that creates a second reconstructed image by performing an image reconstructed process according to the second image reconstructed condition based on the projection data.
A third reconstructed image creation function that creates a third reconstructed image by adding the first reconstructed image and the second reconstructed image, and
With specific functions
It is a control program characterized by executing
The input received by the input device is an input of the radiation dose and the image noise amount in the third reconstructed image, or the radiation dose and the image noise amount in the third reconstructed image, and the said. An input that includes at least one of the first image reconstruction condition and the second image reconstruction condition, or the first image reconstruction condition, the second image reconstruction condition, and the dose of the radiation. And an input including at least one of the image noise amounts in the third reconstructed image.
The storage device stores the relationship between the radiation dose, the image noise amount, and the addition ratio of the first reconstructed image and the second reconstructed image.
The specific function specifies the addition ratio based on the input received by the input device and the relationship.
The third reconstructed image creation function is a control program of a radiation tomography apparatus, which creates the third reconstructed image at the addition ratio specified by the specific unit.