Temperature distribution information acquisition device and program

Abstract

To provide a temperature distribution information acquisition device with which it is possible to acquire temperature distribution information in which the influences of image noise are reduced.SOLUTION: The temperature distribution information acquisition device comprises: a calculation unit for calculating a dispersion of CT value of an inspection object from a CT image; a setting unit for converting the dispersion of the CT value into a dispersion of temperature using a conversion table that represents a relationship between the CT value and temperature of the inspection object and setting a temperature resolution with regard to the inspection object on the basis of the temperature dispersion; a conversion unit for converting the CT value of the inspection object in the CT image into a temperature using the conversion table; and a generation unit for generating, in a display mode differentiated for each temperature range based on the set temperature resolution, temperature distribution information in which the temperature distribution of the inspection object is visualized into an image.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a temperature distribution information acquisition device and a program. [Background technology]

[0002] Patent Document 1 discloses an apparatus that converts the CT values ​​of each part (for example, muscle and fat) of an object measured by an X-ray CT apparatus into temperature, and obtains temperature distribution information of the object. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6483473 Summary of the Invention [Problem to be solved by the invention]

[0004] Images captured by X-ray CT devices contain a lot of noise, which causes variations (standard deviation) in the CT values, and these variations are also reflected in the temperature values ​​converted from the CT values. When image information in which temperature values ​​are color-mapped is generated from the temperature distribution information acquired by the device described in Patent Document 1, there is a possibility that a display color different from the actual temperature will be displayed due to the influence of image noise. In other words, it may be difficult to accurately recognize the temperature value of each part.

[0005] The present disclosure has been made in consideration of such problems, and provides a temperature distribution information acquiring device and a program capable of acquiring temperature distribution information with reduced effects of image noise. [Means for solving the problem]

[0006] (1) According to a first aspect of the present disclosure, a temperature distribution information acquisition device includes a calculation unit that calculates a variation in CT value of an object to be inspected from a CT image; a setting unit that converts the variation in CT value into a variation in temperature using a conversion table representing a relationship between the CT value and temperature of the object to be inspected and sets a temperature resolution for the object to be inspected based on the variation in temperature; a conversion unit that converts the CT value of the object to be inspected in the CT image into a temperature using the conversion table; and a generation unit that generates temperature distribution information that visualizes the distribution of the temperature of the object to be inspected in a display mode that differs for each temperature range based on the set temperature resolution.

[0007] (2) According to a second aspect of the present disclosure, in the temperature distribution information acquisition device of the first aspect, the calculation unit accepts designation of a region of interest within the object of examination and calculates the variation in the CT number within the region of interest.

[0008] (3) According to a third aspect of the present disclosure, in the temperature distribution information acquisition device of the first or second aspect, the generation unit creates a lookup table in which a different color is set for each temperature range, and generates the temperature distribution information using the lookup table.

[0009] (4) According to a fourth aspect of the present disclosure, the temperature distribution information acquisition device relating to any one of the first to third aspects further includes an image processing unit that performs image processing on the CT image to reduce image noise, wherein the calculation unit calculates the variation in the CT value of the test object from the CT image after the image processing, and the conversion unit converts the CT value of the test object in the CT image after the image processing to the temperature.

[0010] (5) According to a fifth aspect of the present disclosure, the temperature distribution information acquisition device according to any one of the first to fourth aspects further includes a display unit that displays the temperature distribution information superimposed on the CT image.

[0011] (6) According to a sixth aspect of the present disclosure, the program causes a temperature distribution information acquisition device to execute the following steps: calculating a variation in CT value of the test object from a CT image; converting the variation in CT value into a variation in temperature using a conversion table representing the relationship between the CT value and temperature of the test object and setting a temperature resolution for the test object based on the variation in temperature; converting the CT value of the test object in the CT image into a temperature using the conversion table; and generating temperature distribution information that visualizes the distribution of the temperature of the test object in a display mode that differs for each temperature range based on the set temperature resolution. Effect of the Invention

[0012] According to the temperature distribution information acquisition device and program of the present disclosure, it is possible to acquire temperature distribution information with reduced influence of image noise. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram showing an overall configuration of a temperature distribution information acquisition system according to the present invention. [Diagram 2] 4 is a block diagram for explaining a functional configuration of a processor of the temperature distribution information acquisition device of the present invention. FIG. [Diagram 3] 4 is a first flowchart showing an example of processing by the temperature distribution information acquisition device of the present invention. [Figure 4] FIG. 2 is a first diagram for explaining the function of the temperature distribution information acquisition device of the present invention. [Diagram 5] FIG. 4 is a diagram showing an example of a conversion table according to the present invention; [Figure 6] FIG. 13 is a diagram showing an example of the temperature resolution for each organ according to the present invention. [Figure 7] 5 is a second flowchart showing an example of the process of the temperature distribution information acquisition device of the present invention. [Figure 8] FIG. 2 is a second diagram for explaining the function of the temperature distribution information acquisition device of the present invention. [Figure 9]FIG. 13 is a block diagram illustrating a functional configuration of a processor of a temperature distribution information acquisition device in a modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <First embodiment> Hereinafter, a temperature distribution information acquiring system 1 and a temperature distribution information acquiring device 20 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 8. FIG.

[0015] (Overall configuration of temperature distribution information acquisition system) FIG. 1 is a diagram showing the overall configuration of a temperature distribution information acquisition system according to the present invention. The temperature distribution information acquisition system 1 according to the present invention is a system for displaying an image of the temperature distribution inside an object to be inspected. The object to be inspected is a living body such as a patient undergoing treatment such as thermotherapy, cauterization, or cryotherapy. The object to be inspected is not limited to a human being, and in other embodiments, an animal may be the object to be inspected. In still other embodiments, a non-living body such as food (e.g., fermented food) may be the object to be inspected. In this embodiment, an example in which the object to be inspected is a living body will be described. As shown in FIG. 1, the temperature distribution information acquisition system 1 includes an X-ray CT (Computed Tomography) device 10 and a temperature distribution information acquisition device 20.

[0016] The X-ray CT device 10 irradiates a living body with X-rays and measures the amount of X-ray transmission (the amount of X-rays that have passed through the living body). The X-ray CT device 10 irradiates a living body with X-rays from multiple directions, measures the amount of X-ray transmission for each direction, analyzes the measurement results, and calculates the CT value of each part of the living body. The X-ray CT device 10 then transmits a CT image capable of detecting the calculated CT value to the temperature distribution information acquisition device 20. An existing X-ray CT device can be used as the X-ray CT device 10.

[0017] The CT value is a relative value indicating the degree of X-ray absorption, with air being -1000 and water being 0, and is expressed in units of HU (Hounsfield Unit). The CT value can be calculated, for example, by the method described in Patent Document 1.

[0018] The temperature distribution information acquisition device 20 calculates temperature distribution information of the living body based on the CT value received from the X-ray CT device 10, and displays the temperature distribution of the target object as an image. As shown in Fig. 1, the temperature distribution information acquisition device 20 is configured using a computer including, for example, a processor 200, a memory 201, a storage 202, an interface 203, a display unit 204, and an operation reception unit 205.

[0019] The processor 200 controls the overall operation of the temperature distribution information acquisition device 20 .

[0020] The memory 201 stores instructions and data for the processor 200 to operate based on a program.

[0021] The storage 202 is a so-called auxiliary storage device, and may be, for example, a hard disk drive (HDD) or a solid state drive (SSD).

[0022] The interface 203 is an interface (communication interface) for connecting to the X-ray CT apparatus 10 so as to be able to communicate with it.

[0023] The display unit 204 is a display that displays the temperature distribution information.

[0024] The operation reception unit 205 is an input device that receives input operations by an operator of the temperature distribution information acquisition device 20, and may be, for example, a general mouse, keyboard, touch sensor, or the like.

[0025] (Functional configuration of temperature distribution information acquisition device) FIG. 2 is a block diagram for explaining the functional configuration of the processor of the temperature distribution information acquisition device of the present invention. As shown in FIG. 2, the processor 200 of the temperature distribution information acquisition device 20 operates according to a predetermined program to function as a calculation unit 2001, a setting unit 2002, a conversion unit 2003, and a generation unit 2004.

[0026] The calculation unit 2001 calculates the variation in CT value of a living body from a CT image.

[0027] The setting unit 2002 converts the variation in CT value into the variation in temperature using a conversion table that indicates the relationship between the CT value and the temperature of the living body, and sets the temperature resolution for the living body based on the variation in temperature.

[0028] The conversion unit 2003 converts the CT value of the living body in the CT image into a temperature using a conversion table.

[0029] The generating unit 2004 generates temperature distribution information by imaging the temperature distribution of the living body in a display mode that differs for each temperature range based on the set temperature resolution. For example, the generating unit 2004 creates a lookup table in which a different color is set for each temperature range, and generates the temperature distribution information using the lookup table.

[0030] (Processing flow of temperature distribution information acquisition device) FIG. 3 is a first flowchart showing an example of processing by the temperature distribution information acquisition device of the present invention. First, the flow of the temperature resolution setting process by the temperature distribution information acquisition device 20 will be described in detail with reference to Fig. 3. Here, an example will be described in which the temperature distribution information acquisition device 20 acquires temperature distribution information inside the body of a patient undergoing treatment such as thermotherapy, cauterization, or cryotherapy (particularly, the area to be treated).

[0031] The temperature distribution information acquiring device 20 acquires a CT image from the X-ray CT device 10 (step S01). This CT image is displayed on the display unit 204 of the temperature distribution information acquiring device 20.

[0032] Next, the operation receiving unit 205 of the temperature distribution information acquiring device 20 receives an operation by the operator to designate the target region R1 and the region of interest R2 on the CT image (step S02).

[0033] FIG. 4 is a first diagram for explaining the function of the temperature distribution information acquisition device of the present invention. As shown in Fig. 4, the display unit 204 displays a CT image of the patient acquired from the X-ray CT device 10. While viewing the CT image displayed on the display unit 204, the operator performs an operation to specify a target region R1 for generating temperature distribution information of the patient and a region of interest R2. The target region R1 is, for example, a region indicating an organ to be treated. The region of interest R2 is a region within the target region R1 in which the CT value is closer to uniform, and for example, the operator visually checks the CT image to determine the position for setting the region of interest R2.

[0034] At this time, the range of the target region R1 and the region of interest R2 may be manually specified by the operator using the operation reception unit 205 (such as a mouse).

[0035] Also, when an operator performs an operation to specify a point on a CT image, the calculation unit 2001 of the temperature distribution information acquisition device 20 may automatically set the range of the target region R1 and the region of interest R2 based on the point. For example, the calculation unit 2001 may use known image processing to extract the contour of an organ (e.g., muscle, fat, liver, kidney, etc.) existing around the specified point on the CT image, and set the region within this contour as the target region R1. Also, the calculation unit 2001 may set a circular region at a predetermined distance from the specified point on the CT image as the region of interest R2. The predetermined distance may be a fixed value set in advance for each organ, or the operator may specify an arbitrary value. Also, the region of interest is not limited to a circle, and may be another shape such as a rectangle.

[0036] Note that a plurality of target regions R1 may be set. In addition, when a plurality of target regions R1 are set, one region of interest R2 is set for each of the target regions R1.

[0037] Next, the calculation unit 2001 calculates the variation of the CT value in the region of interest R2 of the target region R1 (step S03). Here, the calculation unit 2001 calculates the standard deviation SD (σ CT ) is calculated.

[0038] When a plurality of target regions R1 (for example, four organs T1 to T4) are set, the calculation unit 2001 calculates the standard deviation SD (σ CT1 ~σ CT4 ) is calculated.

[0039] Furthermore, the setting unit 2002 converts the variation in the CT value into the variation in temperature (step S04). Specifically, the setting unit 2002 calculates the standard deviation SD (σ CT ) to the standard deviation SD(σ T )

[0040]

number

[0041] In addition, in formula (1), f'(T) is the slope of the function f(T) (hereinafter, also referred to as "conversion table") that represents the relationship between the CT value and the temperature.

[0042] FIG. 5 is a diagram showing an example of a conversion table according to the present invention. 5 is a graph showing a linear approximation of the relationship between the CT value and temperature of each of multiple organs T1 to T4 of a living body. For example, the organs T1 to T4 are the liver, muscle, kidney, and fat, respectively. These graphs are calculated in advance based on the measured values ​​of the CT value and temperature of each organ T1 to T4 (for example, the liver, muscle, kidney, and fat), and are recorded in the storage 202 as a conversion table used for converting the CT value to temperature. The same conversion table may be used for all patients.

[0043] Also, a conversion table may be prepared for each group classified by, for example, sex, age, height, weight, etc., and the conversion table corresponding to the group to which the patient belongs may be used.

[0044] For example, it is assumed that an organ T1 is set as the target region R1 in step S02. In this case, the setting unit 2002 uses the gradient f'(T) of the conversion table for the organ T1 to obtain the standard deviation SD(σ CT ) and the standard deviation of temperature SD(σ T )

[0045] When a plurality of target regions R1 (for example, four organs T1 to T4) are set, the setting unit 2002 sets the standard deviation SD (σ CT1 ~σ CT4 ) to the standard deviation SD(σ T1 ~σ T4 )

[0046] Next, the setting unit 2002 calculates the standard deviation SD (σ T ) based on the temperature resolution in the target region R1 (step S05). For example, the setting unit 2002 sets the temperature resolution based on the standard deviation SD(σ T ), which is twice the value of 2σ T (i.e. ±σ T (range) is set as the temperature resolution of the target region R1.

[0047] FIG. 6 is a diagram showing an example of the temperature resolution for each organ according to the present invention. As in the example of FIG. 6, when a plurality of target regions R1 (for example, four organs T1 to T4) are set, the setting unit 2002 sets the temperature resolution of each target region.

[0048] In the example of FIG. 6, the setting unit 2002 sets the standard deviation SD (σ CT1 = 1.3) and the slope of the conversion table for organ T1 (-0.5) are substituted into the above formula (1) to obtain the standard deviation SD of temperature (σ T1=2.6). In addition, the setting unit 2002 converts the temperature resolution of the organ T1 into 2σ T The setting unit 2002 sets the temperature resolution of each of the other target regions R1 (organs T2, T3, and T4) in the same manner.

[0049] In addition, when one CT image includes multiple target regions R1, the setting unit 2002 may set one temperature resolution to be applied to the entire CT image according to the one having the highest (worst) temperature resolution among the multiple target regions R1. In the example of Fig. 6, since the temperature resolution of the organ T3 (9.4) is the highest, the setting unit 2002 sets the value (10.0) obtained by rounding up the temperature resolution of this organ T3 as the temperature resolution of the entire CT image.

[0050] The temperature distribution information acquisition device 20 performs the series of processes shown in Fig. 3 once, for example, immediately before treating a patient. When treating another patient, the temperature distribution information acquisition device 20 performs the series of processes shown in Fig. 3 again to set a temperature resolution appropriate for the patient.

[0051] Furthermore, when the imaging conditions of the X-ray CT device 10 are changed during treatment of a patient, the variation in the CT value may change. In this case, the temperature distribution information acquisition device 20 may perform the series of processes in FIG. 3 again to update the temperature resolution for this patient.

[0052] FIG. 7 is a second flowchart showing an example of the process of the temperature distribution information acquisition device of the present invention. Next, the flow of the temperature distribution information generation process by the temperature distribution information acquisition device 20 will be described in detail with reference to Fig. 7. When the setting of the temperature resolution is completed by the series of processes in Fig. 3, the temperature distribution information acquisition device 20 executes the process of generating temperature distribution information of the target region during treatment.

[0053] 7, the temperature distribution information acquiring device 20 acquires a CT image from the X-ray CT device 10 (step S11). This CT image is displayed on the display unit 204 of the temperature distribution information acquiring device 20.

[0054] Next, the conversion unit 2003 converts the CT value of the target region R1 into a temperature using the conversion table f(T) for the target region R1 (step S12).

[0055] Next, the generation unit 2004 creates a lookup table D1 (FIG. 8) in which a different color is assigned to each temperature range based on the temperature resolution set by the setting unit 2002, and generates temperature distribution information D2 (FIG. 8) in which the temperature distribution of the target region R1 is color-coded using this lookup table D1 (step S13).

[0056] FIG. 8 is a second diagram for explaining the function of the temperature distribution information acquisition device of the present invention. As shown in FIG. 8, the lookup table D1 defines a predetermined temperature range with a temperature resolution of 2σ T The lookup table D1 is a table in which the temperature range is divided into eight gradations and a different color is set for each gradation. In the example of FIG. 8, the temperature range is −20° C. to 60° C. and the temperature resolution is 10.0° C. Therefore, the lookup table D1 is divided into eight gradations and a different color is set for each gradation. As shown in FIG. 8, the lookup table D1 may be displayed on the display unit 204 so that the operator can understand the correspondence between the color and the temperature. The lookup table D1 may also include information indicating the body temperature of the patient when the CT image was taken.

[0057] The generating unit 2004 references the lookup table D1 and generates temperature distribution information D2, which is an image in which each portion (each pixel) of the target region R1 is painted in a color corresponding to the temperature.

[0058] Furthermore, the display unit 204 superimposes the temperature distribution information D2 generated by the generation unit 2004 on the CT image (step S14), allowing the operator to easily grasp the temperature distribution of the target region R1 (treatment site of the patient) on the CT image.

[0059] The temperature distribution information acquiring device 20 may perform the series of processes shown in Fig. 7 each time a CT image is captured before, during, and after performing thermotherapy on a patient. This allows the operator to perform treatment while checking whether the treatment site is at an appropriate temperature.

[0060] (Effects of the temperature distribution information acquisition device) As described above, the temperature distribution information acquiring device 20 according to the present invention obtains the temperature variation from the CT number variation of a living body (test subject) in a CT image, and sets the temperature resolution for the living body based on this temperature variation. The temperature distribution information acquiring device 20 also generates temperature distribution information that visualizes the distribution of temperature converted from the CT number of the living body in a different display mode (color) for each temperature range based on the temperature resolution.

[0061] In this way, the temperature distribution information acquiring device 20 can acquire temperature distribution information in which the temperature variation caused by image noise is reduced.

[0062] Moreover, the temperature distribution information acquiring device 20 displays this temperature distribution information in a superimposed manner on the CT image.

[0063] In this manner, the temperature distribution information acquiring device 20 can allow the operator to easily understand whether the temperature distribution within the living body has been brought to an appropriate state as a result of treatment such as hyperthermia.

[0064] <Modification> FIG. 9 is a block diagram for explaining the functional configuration of a processor in a temperature distribution information acquisition device in a modified example of the present invention. As shown in FIG. 9, the processor 200 of the temperature distribution information acquisition device 20 according to the modified example may further function as an image processing unit 2005.

[0065] The image processing unit 2005 performs image processing for reducing image noise on the CT image received from the X-ray CT apparatus 10. The image processing is, for example, smoothing processing.

[0066] In the modified example of the present invention, in step S01 of Fig. 3, the image processing unit 2005 performs image processing (such as smoothing processing) to reduce image noise on the CT image acquired from the X-ray CT device 10. In this case, in step S03 of Fig. 3, the calculation unit 2001 calculates the variation in CT value based on the CT image after image processing.

[0067] Similarly, in step S11 of Fig. 7, the image processing unit 2005 performs image processing to reduce image noise on the CT image acquired from the X-ray CT device 10. In this case, in step S12 of Fig. 7, the conversion unit 2003 converts the CT value into temperature based on the CT image after image processing.

[0068] In this way, the temperature distribution information acquiring device 20 can acquire temperature distribution information with further reduced influence of image noise.

[0069] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and gist of the invention. [Explanation of symbols]

[0070] 1. Temperature distribution information acquisition system 10 X-ray CT device 20 Temperature distribution information acquisition device 200 processors 2001 Calculation Department 2002 Setting Department 2003 Conversion Department 2004 Generator 2005 Image Processing Unit 201 Memory 202 Storage 203 Interface 204 Display section 205 Operation reception section

Claims

1. A calculation unit that calculates the variation in CT value of the inspection object from the CT image; a setting unit that converts the variation in the CT number into a variation in temperature using a conversion table that indicates a relationship between the CT number and the temperature of the object to be inspected, and sets a temperature resolution for the object to be inspected based on the variation in temperature; a conversion unit that converts the CT value of the object in the CT image into a temperature using the conversion table; a generating unit that generates temperature distribution information by imaging the distribution of the temperature of the inspection object in a display mode that differs for each temperature range based on the set temperature resolution; A temperature distribution information acquisition device comprising:

2. The calculation unit receives a designation of a region of interest within the examination object, and calculates a variation in the CT value within the region of interest. The temperature distribution information acquisition device according to claim 1 .

3. the generating unit creates a lookup table in which a different color is set for each of the temperature ranges, and generates the temperature distribution information using the lookup table. The temperature distribution information acquisition device according to claim 1 .

4. An image processing unit that performs image processing on the CT image to reduce image noise, The calculation unit calculates a variation in the CT value of the object from the CT image after the image processing, The conversion unit converts the CT value of the object in the CT image after the image processing into the temperature. The temperature distribution information acquiring device according to claim 1 .

5. a display unit that displays the temperature distribution information superimposed on the CT image, The temperature distribution information acquiring device according to claim 1 .

6. Calculating the variation in CT value of the object from the CT image; converting the variation in the CT number into a variation in temperature using a conversion table that indicates a relationship between the CT number and the temperature of the object to be inspected, and setting a temperature resolution for the object to be inspected based on the variation in temperature; converting the CT value of the object in the CT image into a temperature using the conversion table; generating temperature distribution information by imaging the distribution of the temperature of the inspection object in a display mode that differs for each temperature range based on the set temperature resolution; A program for causing a temperature distribution information acquisition device to execute the above.

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