JP2016202329A - Exposure dose calculation device, exposure dose management system, and control method and program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure dose calculation device capable of easily acquiring an expose dose according to a body type of a subject.SOLUTION: Using a Raysum image generated from a plurality of medical images acquired by photographing a subject by an X-ray device, an exposure dose calculation device identifies body type information on at least one of a body width and a body thickness of the subject, acquires a correction coefficient corresponding to the body type information on at least one of the identified body width and the identified body thickness from storage means for storing relationships between the body type information and the correction coefficient, and, from the acquired correction coefficient and a value indicating X-ray intensity at the time when the medical images are taken, calculates an exposure dose according to the body type of the subject, thereby easily acquiring the exposure dose(an exposure dose index) according to the body type of the subject.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an exposure dose calculation device, an exposure dose management system, a control method thereof, and a program thereof.

  In a medical image diagnosis taken using an X-ray CT apparatus or the like, it is common that an exposure dose value (CTDIvol: Volume Computed Tomography Dose Index) received during CT imaging is used as an index for managing the amount of exposure of the subject. It is. In such an X-ray CT apparatus, a detector is attached to a cylindrical reference phantom made of an acrylic resin (hereinafter also referred to as a CTDI phantom) at the time of shipment, and an X-ray dose is detected. Settings are being made. Therefore, CTDIvol can be output as supplementary information of medical image data as a value according to imaging conditions such as X-ray tube current during CT imaging, and CTDIvol can be used as an evaluation index of the exposure dose of the subject.

  CTDI phantoms used for initial setting of the apparatus include those for a body diameter of 32 cm and those for a head of 16 cm in consideration of the size of the examination site of the subject. The reference value acquired based on the phantom is stored, and CTDIvol calculated based on the reference value corresponding to the examination site is output as supplementary information of the medical image data. Thus, CTDIvol output as supplementary information of medical image data can be used as an evaluation index of the exposure dose of the subject, but does not strictly consider the body type of the subject, and depends on the body type of the subject. There was a need for a mechanism to calculate the exposure dose.

  As a technique capable of calculating an exposure dose in consideration of a body shape, Patent Document 1 discloses a body shape of a subject from a scan image (for example, an AP scan image: AP SCAN PROJECTION IMAGE) scanned with the subject lying on a bed. And a method of correcting CTDIvol to a value corresponding to the body shape is disclosed.

JP 2004-73397 A

  However, since the AP scan image used when obtaining the body shape in Patent Document 1 is not an image photographed by rotating the gantry, it is photographed as shown in FIGS. 14 (a-1) to (a-3). The distance between the subject 1400 and the X-ray tube 1402 and the X-ray detector 1403 changes according to the position of the bed 1301 when the bed is moved. The AP scan image captured in FIG. 14 (a-1) is FIG. 14 (b-1), the AP scan image captured in FIG. 14 (a-2) is FIG. 14 (b-2), The AP scan image photographed in FIG. 14A-3 is FIG. 14B-3. As described above, even if the subject is the same, the images are not always the same as shown in FIGS. 14B-1 to 14B-3. That is, since the body width obtained from the AP scan image varies depending on the distance from the X-ray tube 1402, it can be said that the exposure dose according to the body shape of the subject can be reliably calculated by the method disclosed in Patent Document 1. Absent.

  As a method of removing distortion caused by such an AP scan image, there is a method of acquiring body type information of a subject from a tomographic image taken while rotating a gantry with an X-ray CT apparatus. However, since recent CT imaging has taken a plurality of tomographic images, in order to calculate the exposure dose from such a plurality of tomographic images, after specifying any one tomographic image, from the image It is necessary to obtain body type information, which can be said to be quite complicated.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an exposure dose calculation apparatus that can easily acquire an exposure dose according to the body shape of a subject.

In order to achieve the above object, the exposure dose calculation apparatus according to the present invention uses a laysum image generated from a plurality of medical images, and specifies a body type information including at least one of a body width and a body thickness of the subject An acquisition means for acquiring a correction coefficient corresponding to the body shape information specified by the specifying means from a storage means for storing a relationship between the body shape information and the correction coefficient; and the correction coefficient acquired by the acquisition means and the medical use And a calculating means for calculating an exposure dose according to the body shape of the subject from a value indicating the X-ray intensity at the time of image capturing.
Exposure dose calculation device

  In this way, the value correction indicating the X-ray intensity at the time of medical image photographing is performed using the body type information including at least one of the body width and the body thickness of the subject specified by using the laysum image generated from a plurality of medical images. Thus, it is possible to easily obtain an index of the exposure dose according to the body shape of the subject.

It is a figure which shows an example of the system configuration | structure of an exposure dose management system. 2 is a diagram illustrating an example of a hardware configuration of a medical image display apparatus (information processing apparatus) 102 and server apparatuses 103 and 104. FIG. It is a flowchart for demonstrating the flow which calculates the exposure dose according to the physique of a subject. It is an example of the initial screen of a medical image display apparatus. It is an example of an exposure dose management screen. It is an example of an exposure dose management screen. It is a figure explaining the process which produces | generates a Latham image (AP direction). It is a figure explaining the process which produces | generates a Latham image (Lateral direction). It is a correction table which shows the correction coefficient with respect to the body width and the body thickness of the subject used when correcting the exposure dose according to the body type of the subject. It is a flowchart for demonstrating the flow which displays an exposure dose graph. It is a list screen which displays a patient's exposure dose. It is an example of an exposure dose graph. It is an example of an exposure dose graph. It is a figure for demonstrating the problem in a prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration of an exposure dose management system in the present embodiment.

  The exposure dose management system of the present invention includes a modality 101 such as an X-ray CT apparatus, a medical image display device 102 (exposure dose calculation device), an in-hospital image management server 103 (server device), and a LAN (Local Area Network) or WAN. They are connected to each other via a hospital network such as (Wide Area Network) so that data communication is possible. Furthermore, the hospital network can also be connected to an out-of-hospital image management server 104 (exposure dose management apparatus) via the network so that data communication can be performed with each other, and in-hospital images can be stored outside the hospital.

  Note that each terminal configuration in FIG. 1 is an example, and it goes without saying that there are various configuration examples depending on applications and purposes.

  Hereinafter, in this embodiment, an X-ray CT apparatus will be described as an example as a modality, but the present invention is not limited to this, and any modality that requires dose management is applicable.

  The X-ray CT apparatus 101 can transmit and store a captured medical image to a medical image display apparatus 102 set in advance, an in-hospital image management server 103, or an external image management server 104. Medical image data (DICOM image data) imaged by the X-ray CT apparatus 101 and transmitted to the server includes the patient name, patient ID, patient sex, the value of the X-ray tube current at the time of imaging by the X-ray CT apparatus, It consists of incidental information such as CTDIvol (dose information) indicating the X-ray intensity at the time of medical image capturing and image data.

  The medical image display apparatus 102 is a workstation that can perform various image processing based on medical image data (a plurality of tomographic image data) captured by the X-ray CT apparatus 101. In the present embodiment, the medical image display apparatus 102 generates a laysum image obtained by viewing a plurality of tomographic images taken by the X-ray CT apparatus 101 from a predetermined direction, and the body shape index of the subject on the laysum image. Body width and / or body thickness values are acquired, correction values are acquired from the correction value table using values corresponding to the body type of the subject, and CTDIvol provided in the incidental information of DICOM image data By correcting, the exposure dose reflecting the body shape of the subject is calculated.

  The image management server 103 is a server device for storing and managing images captured mainly by in-hospital modalities. The image management server 103 is a medical image transmitted from the modality or after being processed by the medical image display device 102. Medical images can also be saved. By accessing the image management server 103 from an in-hospital information processing apparatus (not shown), it is possible to browse medical images in the image management server 103 from a desired location.

  The image management server 103 is a server device that is provided outside the hospital and can store and manage medical images taken from hospital modalities, medical images processed by the medical image display device 102, and the like. . The image management server 103 can receive storage requests from a plurality of hospitals and can manage radiation doses at a plurality of hospitals.

  FIG. 2 is a diagram illustrating an example of a hardware configuration of the medical image display apparatus 102, the image management server 103, and the image management server 104.

  The CPU 201 comprehensively controls each device and controller connected to the system bus 204.

  Further, the ROM 202 or the external memory 211 (storage means) has a BIOS (Basic Input / Output System) or an operating system program (hereinafter referred to as OS), a medical image display device 102, an image management server 103, an image, and the like as a control program of the CPU 201. Various programs described below necessary for realizing the function executed by the management server 104 are stored. The RAM 203 functions as a main memory, work area, and the like for the CPU 201.

  The CPU 201 implements various operations by loading a program necessary for execution of processing into the RAM 203 and executing the program.

  The input controller 205 controls input from an input device 209 such as a keyboard or a pointing device such as a mouse (not shown).

  The video controller 206 controls display on a display device such as the display 210. The type of the display device is assumed to be a CRT or a liquid crystal display, but is not limited thereto.

  The memory controller 207 is a card type memory connected via an adapter to a hard disk, a flexible disk, or a PCMCIA card slot for storing a boot program, browser software, various applications, font data, user files, editing files, various data, etc. The access to the external memory 211 is controlled.

  A communication I / F controller (communication I / FC) 208 is connected to and communicates with an external device via a network, and executes communication control processing in the network. For example, Internet communication using TCP / IP is possible.

  Note that the CPU 201 enables display on the display 210 by executing outline font rasterization processing on a display information area in the RAM 203, for example.

Further, the CPU 201 enables a user instruction with a mouse cursor (not shown) on the display 210.

Various programs and the like used for each terminal of the present invention to execute various processes to be described later are recorded in the external memory 211, and are executed by the CPU 201 by being loaded into the RAM 203 as necessary.
Furthermore, definition files and various information tables used by the program according to the present invention are stored in the external memory 211.

  Next, the flow of calculating the exposure dose reflecting the body shape of the subject will be described with reference to FIGS.

  FIG. 3 is a flowchart showing processing performed by the medical image display apparatus 102 according to the embodiment of the present invention. The process shown in the flowchart of FIG. 3 is realized by the CPU 201 reading and executing the stored control program. FIG. 4 is an example of an initial screen of the image processing program of the medical image display apparatus 102. FIG. 5 is an example of an initial screen of the dose management screen 500 displayed on the medical image display apparatus 102. FIG. 6 is an example of a state in which the exposure dose reflecting the body type of the subject is calculated on the dose management screen 500 displayed on the medical image display apparatus 102. FIG. 7 is a diagram for explaining a laysum image in the front-rear direction of the subject. FIG. 8 is a diagram for explaining a left-right laysum image of the subject. FIG. 9 shows a correction coefficient 903 used when correcting the CTDIvol to correspond to the body shape of the subject stored in advance in the storage means of the medical image display apparatus 102, and the body shape information (body width + body thickness) of the subject. 901, body thickness 911, body width 921), and effective diameter 912. FIGS. 9A to 9C show the correction coefficient used when correcting the CTDIvol calculated based on the initial value acquired with the 16 cm phantom according to the body shape, the body shape information and the effective diameter of the subject. It is a table which shows. FIGS. 9D to 9F show the correction coefficient used when correcting the CTDIvol calculated based on the initial value acquired with the 32 cm phantom according to the body shape, the body shape information and the effective diameter of the subject. It is a table which shows.

  In S301 of FIG. 3, the CPU 201 of the medical image display apparatus 102 determines whether the dose management tool has been activated. If it is determined that the dose management tool has been activated, the process proceeds to S302.

  Specifically, it can be determined whether or not the dose management button 446 is pressed on the initial screen of the medical image processing program installed in the medical image display apparatus 102 shown in FIG.

  The initial screen of the medical image display apparatus 102 in FIG. 4 is displayed in the medical image display apparatus 102 or image management by pressing the search button 405 in a state where the patient name 401, patient ID 402, examination date 406, calendar 407, etc. are selected. Medical images stored in the servers 103 and 104 can be searched.

  As the retrieved information, information acquired from supplementary information of medical image data such as patient name 411, patient ID 412, gender 413, latest date 414, modality 415, age 416, state 417, and comment 418 is displayed as a list screen 410. Is done.

  When the user selects a desired patient on the list screen 410, examination information such as the patient attribute 421, examination date 422, modality 423, examination description 424, patient name 425, examination ID 426, etc. is displayed on the examination information list screen 420. Is done. When the user selects desired inspection information on the inspection information list screen 420, the series number of the inspection information is displayed on the series information list screen 430. Series information such as 431, pixel size 432, FOV 433, inspection date and time 434, modality 435, slice thickness 436, number of images 437, and the like are displayed. When any series information is selected, thumbnails or the like of images of the series can be displayed in the display area 440.

  Further, the user selects, for example, a plurality of tomographic images captured by the X-ray CT apparatus 101 in a state where desired series information is selected on the series information list screen 430 (or a state where one image in the series is selected). In addition, a 3D drawing button 441 for performing three-dimensional display, a viewer button 442 for viewing a tomographic image, a printer transfer button 443, a report registration button 444 for registering a report, and saving a selected image in the image management servers 103 and 104 An instruction for performing each desired process such as an external storage button 445 for performing a dose calculation, a dose management button 446 for performing a dose calculation process, and the like can be given. It is also possible to select a desired medical image after pressing a button for starting each desired process.

  In S302, the CPU 201 of the medical image display apparatus 102 reads the medical image data (DICOM image data) selected by the user. If a series is selected before the dose management button 446 is pressed, the medical image data of the selected series is read. On the other hand, if not selected, the medical image data can be read by pressing the DICOM image reading button 511 on the exposure dose management screen in FIG. 5 and selecting the medical image data for which the exposure dose is to be calculated.

  In S303, the CPU 201 of the medical image display apparatus 102 acquires dose information (CTDIvol) and the like from the medical image data acquired in S302. Specifically, when the DICOM image data is read, the subject parameter 512 for performing dose calculation, the CTDIvol for the CT dose index 514, and the parameters for dose calculation shown in the dose management screen 500 of FIG. 5 from the incidental information of the DICOM data. 515 etc. are read. (Fig. 6)

  In S304, the CPU 201 of the medical image display apparatus 102 displays a dose management screen 500 shown in FIG. 5, and accepts a designation of a calculation processing method and other inputs from the user via this screen.

  In step S <b> 305, the CPU 201 of the medical image display apparatus 102 determines which is the body shape calculation processing method designated by the user.

  Specifically, the calculation processing method is designated by the user selecting a calculation method for the body type of the subject on the dose management screen of FIG. The body type information of the subject can be acquired from a laysum image generated based on a plurality of medical images (tomographic images) acquired as DICOM image data. Does the user use the body width acquired from the AP image (front-rear direction image) of the subject as the body shape (AP diameter), or uses the body thickness acquired from the lateral image (left-right direction image) (Lateral diameter)? ), Whether to use both body width and body thickness (Lateral + AP diameter) can be selected in the selection field 523.

  Furthermore, the user can select the setting of the user selection item 513, the phantom size of the exposure dose calculation parameter 518, and the like on the dose management screen. If the phantom size and the like can be acquired from the accompanying information of the DICOM data, the contents of the DICOM data are reflected.

  In addition, when dose information (CTDIvol) cannot be acquired from incidental information of DICOM data, a user can input appropriately on a dose management screen.

  If it is determined in S305 that the body width obtained from the AP image is used as the body shape information of the subject (AP diameter is selected), the process proceeds to S306, and the CPU 201 of the medical image display apparatus 102 extracts a laysum image from a plurality of medical images. Generated and displayed in the display area 516.

  For example, in the X-ray CT apparatus 101, imaging is performed with the subject lying on the bed 701 as shown in FIG. 7A, and a plurality of tomographic images as shown in FIG. The laysum image is an image generated based on a value obtained by integrating the CT values of the plurality of tomographic images (or volume images) along a predetermined direction. FIG. 7C shows an example of an AP image generated along the direction (AP direction) from the front surface to the rear surface of the subject. The generated ray-sum image is displayed in the display area 516 of the dose management screen 500.

  In step S307, the CPU 201 of the medical image display apparatus 102 acquires body width information of the subject specified by the laysum image generated in step S306. As an acquisition method, the width of the subject at the center position in the body axis direction of the subject in the region examined by the X-ray CT apparatus can be automatically obtained from the laysum image. In addition, it is possible to accept designation of two points from the user for the laysum image displayed in the display area 516 of FIG. 6 (611), and obtain the distance between the two points as body width information.

  In S308, the CPU 201 of the medical image display apparatus 102 acquires the phantom size. The phantom size can be referred to when there is data in the accompanying information of the DICOM data. On the other hand, when there is no phantom size data in the incidental information of DICOM data, information set by the user via the exposure dose calculation parameter 518 of the dose management screen 500 is acquired.

  In step S308, the CPU 201 of the medical image display apparatus 102 specifies a table to be used based on the body width information acquired in step S307 and the phantom size acquired in step S308, and further acquires a correction coefficient from the table. To do.

  In S318, the CPU 201 of the medical image display apparatus 102 corrects (integrates) the dose information (CTDIvol) acquired in S303 using the correction coefficient acquired in S308, and corrects the exposure dose according to the body type of the subject. Is calculated.

  In S319, the CPU 201 of the medical image display apparatus 102 stores the ray-sum image generated in S306, the exposure dose calculated in S318, and the like in the storage unit. Such storage processing can be automatically performed after the exposure dose is calculated, but may be stored when the user presses the data storage button 522 of the dose management screen 500.

  Further, the storage means to be stored may be storage means in the medical image display apparatus 102 or may be stored in the database 1040 on the image management server 104 outside the hospital.

  Next, in steps S304 to S309, S318, and S319, AP diameter is selected in the selection field 523 in FIG. 6 (601), and the distance between the two points is represented by the AP-direction laysum image displayed in the display area 516. This will be specifically described based on an example in which 32 cm is used as the width information and the phantom.

  When “20.6 cm” is acquired as the distance (body width information) between two points of the laysum image displayed in the display area 516, the information is displayed in the column 602 of the dose management screen 500. The In the display area 517, a medical image of the surface from which body width information has been acquired is displayed.

  9F, which is a correction table corresponding to the AP image of the 32 cm phantom, is specified from the storage unit of the medical image display apparatus 102, and the correction coefficient “20.6 cm” corresponding to “20.6 cm” is determined based on the correction table. 1.48 ”and effective coefficient“ 25 ”are acquired. Even when the correction table is not provided, a necessary correction coefficient can be obtained as appropriate based on correction coefficients corresponding to two adjacent body widths. The acquired correction coefficient “1.48” is displayed in the conversion coefficient column 519, and the effective coefficient “25” is displayed in the effective coefficient column.

  When the CTDIvol acquired from the incidental information of the DICOM data is “8.9216” as shown in the CT dose index column 603 of FIG. 6, the correction coefficient “1.48” and the CTDIvol “8.9216” are used. And “13.204” is calculated as the exposure dose according to the body width.

  Note that the two points that can be selected in the display area 516 in FIG. 6 are selected at the center position in the body axis direction of the layham image in this embodiment, but are acquired at any position in the Z axis direction of the layham image. May be. In that case, the exposure dose according to the body shape can be calculated based on the body width (body shape) acquired at this time.

  By pressing the data save button 522 in such a state, the correction coefficient “1.48” and the exposure dose “13.204” are saved together with the subject information acquired from the DICOM image.

  In addition, as shown in this example, by accepting a desired designated site from the user on the latham image and calculating the exposure dose according to the body shape of the corresponding subject, the exposure dose for the imaging position including the desired organ can be obtained. It can be easily calculated.

  Returning to FIG. 3, the description will be continued. When it is determined in S305 of FIG. 3 that the body thickness obtained from the lateral image is used as the body shape information of the subject (when the lateral diameter is selected), the process proceeds to S310. In step S <b> 310, the CPU 201 of the medical image display apparatus 102 generates a laysum image from a plurality of medical images and displays it in the display area 516. In this case, as shown in FIG. 8 (a), a lateral image (FIG. 8 (b)) obtained by accumulating CT values along the direction (lateral direction) from the left surface to the right surface of the subject is dose management. It is displayed in the display area 516 of the screen 500.

  In S <b> 311, the CPU 201 of the medical image display apparatus 102 acquires the body thickness information of the subject specified by the laysum image generated in S <b> 310. As an acquisition method, the image may be acquired automatically from the laysum image, or the user accepts designation of two points for the laysum image displayed in the display area 516 of FIG. 6 (611), and between the two points Can be acquired as body thickness information.

  In step S312, the CPU 201 of the medical image display apparatus 102 acquires the phantom size. The phantom size can be referred to when there is data in the incidental information of the DICOM data. If there is no data in the incidental information of the DICOM data, the user can calculate the exposure dose calculation parameter on the dose management screen 500. What is set via 518 is acquired.

  In step S313, the CPU 201 of the medical image display apparatus 102 identifies a table to be used based on the body thickness information acquired in step S311 and the phantom size acquired in step S312, and further acquires a correction coefficient from the table. To do.

  In S318, the CPU 201 of the medical image display apparatus 102 corrects (integrates) the dose information (CTDIvol) acquired in S303 using the correction coefficient acquired in S313, and corrects the exposure dose according to the body type of the subject. Is calculated.

  In S319, the CPU 201 of the medical image display apparatus 102 stores the ray-sum image generated in S310, the exposure dose calculated in S318, and the like in the storage unit. Such storage processing can be automatically performed after the exposure dose is calculated, but may be stored when the user presses the data storage button 522 of the dose management screen 500.

  As described above, when the body type information of the subject is obtained using the lateral laysum image, the exposure dose can be calculated in the same manner as the case of obtaining the body type information of the subject using the AP direction laysum image.

  If it is determined in S305 that the body width and body thickness obtained from the AP image and the lateral image are used as the body shape information of the subject (when Lateral + AP diameter is selected), the process proceeds to S314.

  In S <b> 314, as in S <b> 306 and S <b> 310, the CPU 201 of the medical image display apparatus 102 generates two laysum images in the AP direction and the lateral direction from a plurality of medical images and displays them in the display area 516.

  In S315, as in S307 and S311, the CPU 201 of the medical image display apparatus 102 acquires the body width and body thickness information of the subject specified by the laysum image generated in S314.

  In S316, as in S308 and S312, the CPU 201 of the medical image display apparatus 102 acquires the phantom size.

  In S317, as in S309 and S313, the CPU 201 of the medical image display apparatus 102 specifies a table to be used based on the body width and body thickness information acquired in S315 and the phantom size acquired in S316, Further, a correction coefficient is acquired from the table.

  In S318, the CPU 201 of the medical image display apparatus 102 corrects (integrates) the dose information (CTDIvol) acquired in S303 using the correction coefficient acquired in S317, and corrects the exposure dose according to the body type of the subject. Is calculated.

  In S319, the CPU 201 of the medical image display apparatus 102 stores in the storage means the ray-sum image generated in S314, the exposure dose calculated in S318, and the like. Such storage processing can be automatically performed after the exposure dose is calculated, but may be stored when the user presses the data storage button 522 of the dose management screen 500. The storage destination is not limited to the medical image display apparatus 102, but can be stored in the in-hospital image management server 103 or the out-of-hospital image management server 104.

  As described above with reference to FIGS. 3 to 9, in the present embodiment, the subject information of at least one of the body width and the body thickness of the subject specified by using a laysum image generated from a plurality of medical images. Is used to correct CTDIvol, which is the X-ray intensity at the time of medical image capturing.

  The body shape of the subject is obtained from a scan image (for example, AP scan image: AP SCAN PROJECTION IMAGE) that has been scanned while the subject is lying on the bed as disclosed in JP 2004-73397 A, and CTDIvol is calculated. A method for correcting the value according to the body shape has been known. However, since this conventional AP scan image is not an image photographed by rotating the gantry, it depends on the position of the bed 1301 when photographed as shown in FIGS. 14 (a-1) to (a-3). Thus, the distance between the subject 1400, the X-ray tube 1402 and the X-ray detector 1403 changes. The AP scan image captured in FIG. 14 (a-1) is FIG. 14 (b-1), the AP scan image captured in FIG. 14 (a-2) is FIG. 14 (b-2), The AP scan image photographed in FIG. 14A-3 is FIG. 14B-3. As described above, even if the subject is the same, the images are not always the same as shown in FIGS. 14B-1 to 14B-3. In other words, the body width obtained from the AP scan image differs depending on the distance from the X-ray tube 1402, and the method disclosed in Patent Document 1 cannot reliably calculate the exposure dose according to the body shape of the subject.

  On the other hand, in the present embodiment, by acquiring a body shape using a lathe image, the actual body shape of the subject is used compared to the case where the body shape of the subject is used from a scan image taken without rotating the gantry as in the past. Therefore, it can be said that a highly reliable exposure dose can be obtained.

Further, as in the present embodiment, by acquiring the body width and body thickness of the subject from the laysum image, it is possible to reduce the trouble of selecting the position for acquiring the subject information from a plurality of medical images. It can be said that the exposure dose according to the body type of the subject is acquired.
In the present embodiment, the generation of the laysum image from the plurality of medical images (tomographic images) and the calculation of the exposure dose are described as a series of flows.

If the representative value of CTDIvol, which is the X-ray intensity at the time of medical image capturing, is stored, the body shape and the representative CTDIvol can be acquired at a desired timing, and the exposure dose according to the body shape can be calculated. Specifically, after generating any one of the laysum images, the data save button 522 is pressed without specifying 611 two points. Thereby, the representative value of CTDIvol which is the X-ray intensity at the time of radiographic imaging or medical image imaging (for example, DICOM image data at the center of the imaging area is stored without calculating the exposure dose according to the body type of the subject. CTDIvol) is stored. By storing the laysum image in this way, the user obtains the body shape information of the subject from the laysum image at a desired timing, and the exposure dose obtained by correcting CTDIvol, which is a representative value at the time of medical image capturing, according to the body shape. Can be obtained. As a result, it is possible to calculate the exposure dose as appropriate even if a plurality of medical images are not stored to calculate the exposure dose. Therefore, the exposure dose according to the body type of the subject at a desired timing while reducing the capacity of the image management server. Can be calculated.

  Next, a mechanism for managing the exposure dose according to the body shape of the subject will be described with reference to FIGS. The exposure dose calculated as shown in S319 of FIG. 3 can be managed by the medical image display apparatus 102, the in-hospital image management server 103, or the out-of-hospital image management server 104. The exposure dose managed by such management means can be referred to as a list from the medical image display apparatus 102, an information processing apparatus (not shown), or the like. Based on this list information, it is possible to generate a list and an exposure dose management graph by referring to information managed by the management means for the exposure dose.

  Here, an exposure dose management graph generated in response to a graph generation instruction from the medical image display device 102 is displayed based on the exposure dose corresponding to a plurality of subjects managed by the image management server 104 outside the hospital. An example will be described.

  FIG. 10 is a flowchart for explaining a series of flows for displaying an exposure dose graph. The processing shown in the flowchart of FIG. 10 is realized by reading and executing a control program stored in the CPU 201 of the medical image display apparatus 102 and the CPU 201 of the image management server 104. FIG. 11 is a list of exposure doses of a plurality of subjects (patients) managed by the image management server 104, and is generated by the image management server 104 in response to a request from the medical image display device 102. 2 is a list screen displayed at 102. The user can instruct display of the exposure dose graph via this screen. An example of the exposure dose management graph displayed in this way is shown in FIGS.

  In S <b> 1001 of FIG. 10, the CPU 201 of the medical image display apparatus 102 requests the image management server 104 to display a list image.

  In step S <b> 1002, the CPU 201 of the image management server 104 responds to a display request from the medical image display apparatus 102 based on a plurality of X-ray CT examination information managed in the image management server 104, such as a laysum image, exposure dose, and the like. A list screen that can grasp the management information of is generated. At the same time, a display screen 1101 including a list screen and a condition column 1130 for setting a graph display condition is transmitted to the medical image display apparatus 102 in S1003.

  In step S <b> 1004, the CPU 201 of the medical image display apparatus 102 displays the display screen 1101 transmitted from the image management server 104 on the display.

  An example of such a display screen 1101 is shown in FIG. As can be seen from the display screen 1101 shown in FIG. 11, in the image management server 104, the selection box 1102 and the management number 1103, the examination date 1104 acquired from the DICOM data, the patient ID 1105, the patient name 1106, the gender 1107, the age 1108, and the weight 1109 The imaging region 1110 is managed. Furthermore, the number of images 1111 indicating the number of stored laysum images, CTDIvol 1112 which is the X-ray intensity at the time of taking a medical image (specified when the CTDIvol or data save button 522 used to calculate the exposure dose is pressed) DPI 1113 and phantom size 1114 are managed. Further, the exposure dose 1115 calculated by correcting CTDIvol according to the body shape of the subject, the effective diameter 1116 acquired from the correction table, the conversion coefficient 1117, and the like are managed.

  On the list screen, the inspection information in which data is registered after the exposure dose 1115 is calculated and the inspection information in which data is registered in a state where the ray dose image 1115 has been calculated but the exposure dose 1115 has not been calculated can be identified. It is displayed. In the example of FIG. 1 and No. 2 and No. 3 and no. Reference numeral 5 denotes examination information in which data is registered after the exposure dose 1115 corresponding to the body type of the subject is calculated. And No. 4 and no. Reference numeral 6 denotes examination information in which data is registered in a state in which a ray-sum image is generated but an exposure dose 1115 is not calculated. In this example, it is possible to determine which state is in accordance with whether or not a value such as the exposure dose 1115 is entered. By displaying in such a way that it can be judged on the list screen, it is possible to easily confirm whether or not the exposure dose according to the body type of the subject is calculated in the inspection information managed by the exposure dose management means. Can do.

  A new registration button 1118 on the display screen 1101 is a button for registering information such as a new patient's laysum image and exposure dose 1115 without using the dose management screen 500. A delete button 1119 on the display screen 1101 is a button that can delete examination information for which the selection box 1102 is selected. A download button 1120 on the display screen 1101 is a button for downloading information such as a ray-sum image of examination information in which the selection box 1102 is selected and exposure dose 1115 managed as a management item. The overwrite save button on the display screen 1101 is a button for saving the overwrite on the examination information selected in the selection box 1102.

  Here, a Latham image was generated but the exposure dose 1115 was not calculated. 4 or No. The case where it is desired to register the exposure dose according to the body type of the subject for the examination 6 will be described. No. 4 or No. When the download button 1120 is pressed while 6 is selected, the CPU 201 of the medical image display apparatus 102 activates the dose management tool. Then, the corresponding laysum image stored in the management server 104 and the representative value of CTDIvol are acquired. Similar to the flow of calculating the exposure dose described with reference to FIGS. 3 to 9, the subject information of at least one of the body width and the body thickness is specified from the Latham image, and the CTDIvol is corrected using the specified subject information. Calculate the exposure dose.

  In addition, by pressing a data save button 522 on the dose management screen 500, the calculated exposure dose can be overwritten with respect to the downloaded examination information.

  In addition, it is possible to directly save the overwriting without performing the calculation process in the medical image display apparatus 102 as described above.

In this way, even if a plurality of tomographic images are not stored, since the laysum image is stored, the exposure dose can be calculated at a desired timing, and further stored.

  Returning to FIG. 10, the description of the graph generation processing will be continued. In step S1005, the CPU 201 of the medical image display apparatus 102 determines whether the graph display button 1131 has been pressed by the user. If it is determined that the graph display button 1131 has been pressed by the user, the CPU 201 of the medical image display apparatus 102 sends a graph display request to the image management server 104 together with the conditions in the condition column 1130 of the graph display conditions in S1006. I do. Specifically, when the graph display button 1131 is pressed, a graph display request corresponding to the item checked in the condition column 1130 is made to the image management server 104.

  In step S <b> 1007, the CPU 201 of the medical image display apparatus 102 generates a graph according to conditions specified by the user. Specifically, a graph template to be applied for each condition setting is prepared in advance, the template is selected according to the condition set in the condition column 1130, and the data managed as the exposure dose is reflected on the template. To generate a graph.

  In step S <b> 1008, the CPU 201 of the image management server 104 transmits the graph generated in step S <b> 1007 to the medical image display apparatus 102.

  In step S1009, the CPU 201 of the medical image display apparatus 102 displays the graph transmitted from the image management server 104, and the process ends.

  Next, an example of the graph generated in this way will be specifically described. FIG. 12 shows a case where the graph display button 1131 is pressed in the condition column 1130 of FIG. 11 with the imaging region: chest, abdomen, sex: female, male, item: CTDIvol, and exposure dose selected. In this case, a template that is divided into a chest and an abdomen, is divided into a woman and a man, and is divided into a CTDIvol and an exposure dose, and a graph on which managed examination information is plotted is displayed.

  Further, in the condition column 1130 shown in FIG. 11, when the imaging region: chest is checked, the gender: female is checked, the item: CTDIvol is checked, and the percentile display is checked, FIG. A template as shown is selected, and a graph on which inspection information is plotted is displayed.

  Furthermore, in the condition column 1130 shown in FIG. 11, when the imaging region: chest is checked, gender: male is checked, item: exposure dose is checked, and percentile display is checked, FIG. 13 (b) A template as shown in FIG. 5 is selected, and a graph on which inspection information is plotted is displayed.

  In the condition column of FIG. 11, the graph cannot be displayed when any one of the items is not selected. Therefore, when any one is not selected, the graph display button 1131 is grayed out. For example, the selection may be disabled.

  Based on the examination information managed as described above, a graph according to a desired condition can be displayed, so that the user can grasp an index for an appropriate exposure dose.

  The present invention can be implemented as a system, apparatus, method, program, storage medium, or the like, and can be applied to a system including a plurality of devices. You may apply to the apparatus which consists of one apparatus.

  Note that the present invention includes a software program that implements the functions of the above-described embodiments directly or remotely from a system or apparatus. The present invention also includes a case where the information processing apparatus of the system or apparatus is achieved by reading and executing the supplied program code.

  Therefore, the program code itself installed in the information processing apparatus in order to realize the functional processing of the present invention with the information processing apparatus also realizes the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  Examples of the recording medium for supplying the program include a flexible disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, and CD-RW. In addition, there are magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R), and the like.

  As another program supply method, a browser on a client computer is used to connect to an Internet home page. The computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, the present invention also includes a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention with an information processing apparatus.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let The downloaded key information can be used to execute the encrypted program and install it in the information processing apparatus.

  Further, the functions of the above-described embodiment are realized by the information processing apparatus executing the read program. In addition, based on the instructions of the program, the OS or the like operating on the information processing apparatus performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the information processing apparatus or a function expansion unit connected to the information processing apparatus. Thereafter, the CPU of the function expansion board or function expansion unit performs part or all of the actual processing based on the instructions of the program, and the functions of the above-described embodiments are realized by the processing.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

101 Modality 102 Medical Image Display Device 103 Image Management Server 104 Image Management Server

Claims (15)

A specifying means for specifying body type information of at least one of a body width and a body thickness of a subject using a laysum image generated from a plurality of medical images acquired by imaging the subject with an X-ray device;
An acquisition means for acquiring a correction coefficient corresponding to at least one body shape information of the body width and body thickness specified by the specifying means from a storage means for storing a relationship between the body shape information and the correction coefficient;
A calculating means for calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired by the acquiring means and a value indicating the X-ray intensity at the time of medical image capturing;
An exposure dose calculation device comprising:   The exposure dose calculation apparatus according to claim 1, further comprising storage means for storing the exposure dose calculated by the calculation means together with body type information.   The exposure dose calculation apparatus according to claim 2, wherein the storage unit also stores a Latham image used when the specifying unit specifies body type information.   4. The laysum image used by the specifying unit to specify the body type information is at least one of a front-rear direction laysum image and a left-right direction rasom image of the subject. 5. The exposure dose calculation apparatus according to any one of the above items.   5. The exposure dose calculation apparatus according to claim 1, wherein the specifying unit specifies a length of a subject at a central position in a body axis direction of the subject from the latham image. .   The specification unit receives a specification of two positions from a user in a state where the laysum image is displayed, and specifies a distance corresponding to the body shape of the subject from the two points. The exposure dose calculation apparatus according to any one of 1 to 4.   The exposure dose calculation apparatus according to claim 1, wherein the value indicating the X-ray intensity at the time of taking a medical image is CTDIvol. A generation step of generating a laysum image from a plurality of medical images acquired by imaging a subject with an X-ray device;
A specifying step of specifying at least one body type information of the body width and body thickness of the subject using the latham image generated in the generating step;
An acquisition step of acquiring a correction coefficient corresponding to at least one body shape information of the body width and body thickness specified in the specifying step from a storage unit that stores a relationship between the body shape information and the correction coefficient;
A calculation step of calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired in the acquisition step and a value indicating the X-ray intensity at the time of medical image capturing;
A method for controlling an exposure dose calculation apparatus comprising: An executable program for the exposure dose calculation device,
The exposure dose calculation device,
A specifying means for specifying body type information of at least one of a body width and a body thickness of a subject using a laysum image generated from a plurality of medical images acquired by imaging the subject with an X-ray device;
An acquisition means for acquiring a correction coefficient corresponding to at least one body shape information of the body width and body thickness specified by the specifying means from a storage means for storing a relationship between the body shape information and the correction coefficient;
A calculating means for calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired by the acquiring means and a value indicating the X-ray intensity at the time of medical image capturing;
A program characterized by functioning as An exposure dose management system in which an exposure dose calculation device and a server device are connected via a network,
A specifying means for specifying body type information including at least one of a body width and a body thickness of a subject using a latham image generated from a plurality of medical images acquired by imaging the subject with an X-ray device;
Obtaining means for obtaining a correction coefficient corresponding to the body type information specified by the specifying means from a storage means for storing a relationship between the body type information and the correction coefficient;
A calculating means for calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired by the acquiring means and a value indicating the X-ray intensity at the time of medical image capturing;
A dose management system with exposure.     The exposure dose management system according to claim 10, further comprising storage means for storing the exposure dose calculated by the calculation means together with body type information.   12. The exposure dose management according to claim 11, wherein the specifying unit, the acquisition unit, and the calculation unit are provided in the exposure dose calculation device, and the storage unit is provided in the server device. system. The server device
13. The exposure dose management system according to claim 12, further comprising a graph generation unit that generates an exposure dose management graph corresponding to a predetermined condition based on the exposure dose stored in the storage unit. A method for controlling an exposure dose management system in which an exposure dose calculation device and a server device are connected via a network,
A specifying step of identifying body type information including at least one of a body width and a body thickness of a subject using a laysum image generated from a plurality of medical images acquired by imaging the subject with an X-ray device;
An acquisition step of acquiring a correction coefficient corresponding to the body type information specified in the specifying step from a storage unit that stores a relationship between the body type information and the correction coefficient;
A calculation step of calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired in the acquisition step and a value indicating the X-ray intensity at the time of medical image capturing;
A control method comprising: An exposure dose management system in which an exposure dose calculation device and a server device are connected via a network,
The exposure dose management system,
A specifying means for specifying body type information including at least one of a body width and a body thickness of a subject using a latham image generated from a plurality of medical images acquired by imaging the subject with an X-ray device;
Obtaining means for obtaining a correction coefficient corresponding to the body type information specified by the specifying means from a storage means for storing a relationship between the body type information and the correction coefficient;
A calculating means for calculating an exposure dose according to the body shape of the subject from the correction coefficient acquired by the acquiring means and a value indicating the X-ray intensity at the time of medical image capturing;
A program characterized by functioning as

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