JP5448676B2 - Radiography management system - Google Patents

Description

  The present invention relates to a radiography management system and method for managing the exposure dose to a patient during radiography.

  Conventionally, the inside of a human body is diagnosed with a radiographic image by performing radiography using chest X-ray imaging, a mammography apparatus, a CT apparatus, or the like. Since this radiography exposes the human body with a small amount of radiation, it is necessary to manage the radiation exposure in consideration of the safety of the human body. In order to manage the exposure dose, it is necessary to measure the exposure dose, and various methods for measuring the exposure dose have been proposed (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, the irradiation X-ray dose is calculated from the imaging conditions, or the accumulated X-ray dose is detected based on the radiation dose measured by the dosimeter by placing a dosimeter in the irradiation unit or the detection unit. Patent Document 2 discloses, for example, calculating an irradiation dose associated with image data in DICOM or the like.

JP 2004-201757 A JP 2007-97909 A

  However, as in Patent Document 1, there is a problem that a dosimeter is separately required and costs are increased. In addition, when the management based on the radiation dose is performed based on the imaging conditions as in Patent Documents 1 and 2, the accuracy of estimation of the recorded radiation dose itself may be lowered due to the influence of sensitivity fluctuations due to deterioration over time. However, there is a problem that the radiation dose cannot be accurately managed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a radiography management system and method capable of managing a radiography apparatus based on an exposure dose accurately detected with respect to a radiation dose exposed to a patient. Is.

  The radiation imaging management system of the present invention is an exposure by a radiation imaging apparatus that detects radiation transmitted through a subject when the subject is irradiated with radiation from a radiation source that irradiates the subject with a radiation detector and acquires a radiation image. A radiography management system for managing an amount, and detecting a blank region in which radiation from a radiation source is directly detected without passing through a subject from each divided region when a radiation image is divided into a plurality of divided regions. Detecting in the exposure amount detection means, the exposure amount detection means for detecting the divided exposure amount for each divided area using the pixel value of the background loss area detected by the background loss area detection means, and the exposure amount detection means An exposure dose comparison means for comparing a plurality of divided exposure doses, and a device management means for managing a radiographic apparatus based on a comparison result by the exposure dose comparison means. It is an.

  The radiography management method of the present invention is an exposure by a radiography apparatus that detects radiation transmitted through a subject when the subject is irradiated with radiation from a radiation source that irradiates the subject with a radiation detector and acquires a radiation image. A radiography management method for managing the amount of radiation, which divides a radiographic image into a plurality of divided areas and detects a blank area in which radiation from a radiation source is directly detected without passing through a subject from within each divided area. Detecting the divided exposure amount of each divided region using the pixel value of the detected blank region, comparing the plurality of detected divided exposure amounts, and managing the radiation imaging apparatus based on the comparison result It is a feature.

  Here, the radiation imaging apparatus may be anything as long as it detects a radiographic image by detecting radiation that has passed through the subject. For example, it may be a chest X-ray imaging apparatus, a mammography apparatus, a dental apparatus, or an internal organ. It may be a CT apparatus for observation.

  The radiation imaging management apparatus may be built in the radiation imaging apparatus, or connected to a plurality of radiation imaging apparatuses via a network so that data transmission is possible, and manages the plurality of radiation imaging apparatuses. You may do.

  Further, the radiation image or the detection area of the radiation detector may be divided into a plurality of two or more, may be set in advance, or may be set in an arbitrary area via the input means. There may be. In addition, the area division may be performed by dividing the detection area in a matrix shape or in a strip shape regardless of the number of divided areas and the division method.

  The area dividing means may be any means as long as it can divide the area so that the blank area exists in at least two of the divided areas. However, all the divided areas include the blank area. Preferably it is. Further, after the region division, the missing region may be detected from each divided region, or the region division may be performed so that the divided region is included in each divided region after detecting the missing region. Good.

  Note that the apparatus management means may have a function of outputting a warning when the difference between the divided exposure doses is equal to or greater than a set threshold value.

  Further, the apparatus management means may include a data analysis means for calculating statistical data using a divided exposure dose that is less than a set threshold value.

  Furthermore, the apparatus management means has a function of storing the largest maximum divided exposure amount as the exposure amount to the subject among a plurality of divided exposure amounts detected for one radiography. Also good.

  Furthermore, the radiation imaging management system may be built in the radiation imaging apparatus, or connected to a plurality of radiation imaging apparatuses via a network so that data transmission is possible, and manages the plurality of radiation imaging apparatuses. It may be a thing.

  According to the radiography management system and method of the present invention, radiography that acquires radiation images by detecting radiation transmitted through a subject when the subject is irradiated with radiation from a radiation source that irradiates the subject with a radiation detector. The exposure amount is controlled by the device, and the detection area of the radiation detector is divided into a plurality of divided areas, and the radiation from the radiation source is directly detected from each divided area without passing through the subject. Detect the missing area, detect the divided exposure amount of each divided area using the pixel value of the detected blank area, compare the plurality of detected divided exposure amounts, and based on the comparison result, By performing management, it is possible to detect the exposure amount with high accuracy even when sensitivity fluctuations occur in the radiation detector, and to manage the radiation imaging apparatus based on accurate exposure amount detection. Kill.

  In addition, if the device management means has a function of outputting a warning when the difference between the divided exposure amounts is equal to or larger than the set threshold value, the divided exposure amounts are separated from the set threshold value or more. In this case, it is possible to determine that the apparatus needs to be maintained due to sensitivity fluctuations due to deterioration over time, and therefore appropriate maintenance management of the radiation imaging apparatus can be performed.

  Further, when the device management means has a data analysis means for calculating statistical data using the divided exposure dose that is less than the set threshold value, the data using the exposure dose error error due to the sensitivity fluctuation is used. Since it is possible to manage the exposure amount during radiography, appropriate maintenance management of the radiography apparatus can be performed.

  Furthermore, if the device management means has a function of storing the largest maximum divided exposure amount among a plurality of divided exposure amounts as the exposure amount to the subject at the time of radiography, local sensitivity fluctuations Even when the radiation detection performance of a certain divided area deteriorates due to the above or the like, it is possible to accurately detect the exposure amount to the subject based on the detection result of another divided area with little sensitivity variation or the like.

  Furthermore, if it is connected to a plurality of radiation imaging apparatuses via a network so that data transmission is possible and a plurality of radiation imaging apparatuses are managed, a plurality of radiation imaging using a single exposure dose management apparatus is possible. The device can be managed efficiently.

Schematic which shows preferable embodiment of the radiography management system of this invention. 1 is a system diagram showing an example of a radiation imaging apparatus connected to the radiation imaging management system of FIG. The schematic diagram which shows an example of the radiography apparatus connected to the radiography management system of FIG. The schematic diagram which shows an example of the radiation detector in the radiography apparatus of FIG. The schematic diagram which shows an example of the state by which the detection area | region was divided | segmented in the area | region division means of FIG. The schematic diagram which shows another example of the state by which the detection area | region was divided | segmented in the area | region division means of FIG. The flowchart which shows preferable embodiment of the radiography management method of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a preferred embodiment of the radiation imaging management system of the present invention. The radiation imaging management system 1 manages the exposure dose by the radiation imaging apparatus 10 installed in each hospital or the like for each patient, and a plurality of radiation imaging apparatuses 10 and the exposure dose management apparatus 20 are networked. 2 is connected so that data transmission is possible.

  FIG. 2 is a schematic diagram illustrating an example of the radiation imaging apparatus 10. The radiation imaging apparatus 10 in FIG. 2 is a saddle-type radiation imaging apparatus, and includes a radiation source 11 and a radiation detector 12. Then, radiation is applied to the patient S from the radiation source 11, and the radiation transmitted through the patient S is detected as a radiation image by the radiation detector 12. The radiation source 11 and the radiation detector 12 are controlled by the imaging control means 13.

  FIG. 4 is a circuit configuration block diagram of the radiation detector 12. In the radiation detector 12, a photoelectric conversion layer 51 made of a substance such as amorphous selenium (a-Se) that senses radiation and generates charges is arranged on an array of thin film transistors (TFTs) 52. After the charge generated in the photoelectric conversion layer 51 is stored in the storage capacitor 53, the TFTs 52 are sequentially turned on for each row, and the charge stored in the storage capacitor 53 is read as an image signal. In FIG. 4, only the connection relationship between one pixel 50 including the photoelectric conversion layer 51 and the storage capacitor 53 and one TFT 52 is shown, and the configuration of the other pixels 50 is omitted.

  A gate line 54 extending in parallel to the row direction and a signal line 56 extending in parallel to the column direction are connected to the TFT 52 connected to each pixel 50 of the radiation detector 12. Each gate line 54 is connected to a line scan driver 58, and each signal line 56 is connected to a multiplexer 66. Control signals Von and Voff for controlling on / off of the TFTs 52 arranged in the row direction are supplied from the line scanning drive unit 58 to the gate line 54. In this case, the line scan driving unit 58 includes a plurality of switches SW1 for switching the gate lines 54 and an address decoder 60 for outputting a selection signal for selecting one of the switches SW1. The address decoder 60 is supplied with an address signal from the imaging control means 13.

  In addition, the charge held in the storage capacitor 53 of each pixel 50 flows out to the signal line 56 through the TFTs 52 arranged in the column direction. This charge is amplified by the amplifier 62. A multiplexer 66 is connected to the amplifier 62 via a sample and hold circuit 64. The multiplexer 66 includes a plurality of switches SW2 for switching the signal line 56 and an address decoder 68 for outputting a selection signal for selecting one of the switches SW2. Address data 68 is supplied with an address signal from the imaging control means 13. An A / D converter 70 is connected to the multiplexer 66, and a radiographic image signal converted into a digital signal by the A / D converter 70 is output to the imaging control means 13.

In particular, the radiation detector 12 of FIG. 4 includes a multiplexer 66 _{2n + 1} for reading a signal from the TFT52 of odd-numbered pixel lines, and a multiplexer 66 _2n for reading the signals from the even lines TFT. That is, the radiation image signal is output to the imaging control means 13 via the multiplexers 66 _{2n + 1} and 66 _2n different from the TFT 52 of the odd pixel line and the TFT 52 of the even line.

  In FIG. 4, the case where the TFT method is adopted as the radiation detector 12 is illustrated, but an optical readout type radiation detector 12 may be used. Specifically, the radiation detector 12 of the optical readout method is a phosphor material and a photoelectric conversion element (photographing element) instead of the radiation-to-charge conversion material that directly converts the radiation X such as amorphous selenium into charges. It is converted into charge indirectly using a diode. As phosphor materials, gadolinium sulfate (GOS) and cesium iodide (CsI) are well known. In this case, radiation X-light conversion is performed by a fluorescent material, and light-charge conversion is performed by a photodiode of a photoelectric conversion element.

  Further, the radiographic apparatus 10 of FIG. 3 includes an area dividing unit 14, a blank area detecting unit 15, and an exposure amount detecting unit 16. The area dividing means 14 divides the radiation detection area DR or the radiation image P of the radiation detector 12 into a plurality of divided areas BR. In particular, the area dividing unit 14 divides the area so that each divided area BR includes the blank area TER. 5A and 5B are schematic views showing an example in which the detection area is divided. In FIG. 5A, the plurality of divided regions BR1 to BR4 are formed by dividing the detection region DR of the radiation detector 12 into a matrix. Even in the case of a chest X-ray as shown in FIG. 5A, each of the divided regions BR1 to BR4 has a missing region TER.

  In FIG. 5B, the plurality of divided regions BR1 to BR4 are formed by dividing the detection region DR of the radiation detector 12 into strips (stripes). For example, even when the missing region TER exists only on the clavicle as shown in FIG. 3B, the missing region exists in each of the divided regions BR1 to BR4. The divided area BR may be set in advance, or one setting may be selected from a plurality of area division settings and divided.

  Further, the region dividing means 14 is not limited to the region dividing as shown in FIGS. 5A and 5B, and the region dividing unit 14 divides the region into regions formed by even pixel lines and regions formed by odd pixel lines as shown in FIG. You may do it. Further, not only in the case of the radiation detector 12 having the structure as shown in FIG. 4, but also in the case of a normal TFT method or light readout method, the region is divided into even pixel lines and odd pixel lines of the radiation image. It may be.

  The blank area detection means 15 detects a blank area TER in which the radiation from the radiation source 11 is directly detected without passing through the subject S in each of the divided areas BR1 to BR4. It is to be noted that a known technique can be used for the detection of the background region TER. For example, a region having a pixel value greater than or equal to a predetermined size among the pixel values of the radiation image P is detected as the background region TER.

  3 detects the exposure amount in each of the divided regions BR1 to BR4 as the divided exposure amount BDR using the pixel value of the background region TER detected by the background region detection unit 15. It is. It is to be noted that a known technique can be used to detect the exposure amount based on the background region, and the exposure amount detection means 16 is, for example, the pixel average value, maximum pixel value, intermediate value of the background region TER in the divided region BR. A value or the like is detected as the divided exposure dose BDR.

  The warning output unit 17 outputs a warning for alerting the radiation exposure amount of the patient to an operator such as a radiologist or a doctor. For example, the warning output unit 17 outputs a warning as a display unit or a voice.

  The exposure dose management device 20 of FIG. 1 includes an exposure dose comparison unit 21 and a device management unit 22. The exposure dose comparison means 21 compares a plurality of divided exposure doses BDR detected by the exposure dose detection means 16. For example, when the detection area is divided into four divided areas BR1 to BR4 as shown in FIGS. 5A and 5B, six difference values are calculated.

  The apparatus management unit 22 manages the radiation imaging apparatus 10 based on the comparison result in the exposure amount comparison unit 21. Specifically, when it is determined that the difference between the divided exposure doses BDR is equal to or greater than a set threshold value, control is performed to output a warning indicating that maintenance is required via the warning output unit 17. Furthermore, the device management means 22 has a function of creating and storing statistical data relating to radiation imaging based on the divided exposure dose BDR in which a plurality of differences are less than a set threshold value. Specifically, the apparatus management unit 22 analyzes an average value (including a weighted average by one area), a maximum value, and an intermediate value of a plurality of divided exposure doses BDR obtained for each radiography and stores them in the database DB. To do. In particular, the device management means 22 stores the maximum divided exposure dose BDR as the exposure dose irradiated to the patient S. Even when the sensitivity due to aging deteriorates, the maximum divided exposure dose BDR estimated to have the highest sensitivity is managed as the exposure dose irradiated to the patient S, so that the exposure dose with high accuracy can be obtained. Can be managed.

  As described above, the detection area DR is divided into a plurality of divided areas BR1 to BR4, and the divided exposure dose BDR is detected from the blank area TER in each of the divided areas BR1 to BR4, and the comparison result of the divided exposure dose BDR. By managing the radiation imaging apparatus 10 based on the above, it is possible to perform maintenance management based on the detection result of the exposure amount with high accuracy at low cost. In particular, when only one exposure dose is detected from one radiation detector 12 and management is performed based on the detected exposure dose, it is difficult to determine whether or not local sensitivity fluctuations have occurred. It is difficult to determine whether or not management is necessary, and as a result, management may be performed in a state where the detection accuracy of the exposure dose is lowered. On the other hand, the radiation imaging apparatus 10 is managed by the divided exposure amount BDR based on the unexposed area TER for each of the divided areas BR1 to BR4, thereby improving the detection accuracy of the exposure amount to the subject S and the radiation imaging apparatus. Ten states can be grasped with high accuracy.

  FIG. 6 is a flowchart showing a preferred embodiment of the radiography management method of the present invention. The radiography management method will be described with reference to FIGS. When radiation imaging is performed in the radiation imaging apparatus 10, the background missing area is detected for each of the divided areas BR1 to BR4 set in advance in the background missing area detecting means 15 (step ST1). Thereafter, the divided exposure amount BDR is detected by the exposure amount detection means 16 from the blank regions of the divided regions BR1 to BR4 (step ST2).

  Next, the divided exposure dose BDR is transmitted to the apparatus management means 22 via the network 2, and the difference of the divided exposure dose BDR is calculated by the exposure dose comparison means 21 (step ST3). And it is judged in the apparatus management means 22 whether the difference of division | segmentation exposure amount BDR is more than a setting threshold value (step ST4), and the difference of division | segmentation exposure amount BDR is more than a setting threshold value, It is determined that the radiation imaging apparatus 10 has deteriorated due to sensitivity fluctuation or the like, and a warning is output from the warning output means 17 (step ST5). On the other hand, if the difference in the divided exposure dose BDR is less than the set threshold value, the apparatus management means 22 calculates and stores the statistical data of the exposure dose to the patient S using the divided exposure dose data (step) ST6).

  According to the embodiment described above, the radiation imaging apparatus that acquires the radiation image by detecting the radiation transmitted through the subject S by the radiation detector 12 when the subject is irradiated with radiation from the radiation source 11 that irradiates the subject S with radiation. 10 for detecting the amount of exposure by the radiation detector 12, and detecting the blank region TER in which the radiation from the radiation source 11 is directly detected without passing through the subject for each of the divided regions BR in the detection region DR of the radiation detector 12. Then, the divided exposure dose BDR of each divided region is detected using the pixel value of the detected blank region TER, the plurality of detected divided exposure doses BDR are compared, and based on the comparison result, the radiation imaging apparatus 10 Even if radiation detection performance deteriorates due to sensitivity fluctuations, etc., it is possible to detect the exposure amount to the subject with high accuracy and perform radiography based on accurate exposure amount detection. It is possible to carry out the management of the location.

  In addition, when the apparatus management unit 22 has a function of outputting a warning when the difference between the respective divided exposure doses BDR is equal to or larger than the set threshold value, a sensitivity variation or the like due to aged deterioration has occurred. Therefore, appropriate maintenance management of the radiation imaging apparatus can be performed.

  In addition, when the device management means 22 has data analysis means for calculating statistical data using the divided exposure dose BDR that is less than the set threshold value, data with less exposure dose error due to sensitivity fluctuations is obtained. Since it is possible to manage the exposure dose during radiography, appropriate maintenance management of the radiography apparatus 10 can be performed.

  Further, if the apparatus management means has a function of storing the maximum divided exposure dose BDR among the plurality of divided exposure doses BDR as the exposure dose to the subject at the time of radiography, local sensitivity fluctuations, etc. Thus, even when the radiation detection performance of a certain divided region is deteriorated, the exposure amount to the subject can be detected with high accuracy based on the detection result of the other divided regions with little sensitivity variation or the like.

  In addition, if connected to a plurality of radiation imaging apparatuses via a network so as to be able to transmit data and manage a plurality of radiation imaging apparatuses, a plurality of radiation imaging using a single exposure dose management apparatus. The device can be managed efficiently.

  The embodiment of the present invention is not limited to the above embodiment. For example, FIG. 1 illustrates the case where the radiation imaging apparatus 10 and the exposure dose management apparatus 20 are connected via a network so that data transmission is possible. However, the exposure dose management apparatus 20 is connected to the radiation imaging apparatus 10. The radiation amount may be managed in each radiation imaging apparatus 10.

  Further, in the above-described embodiment, the case where the missing region TER is detected after the region division is illustrated, but it is sufficient that the missing region TER exists in two or more different divided regions BR. After the area TER is detected, the area division may be performed so that the divided areas BR1 to BR4 each include the blank area TER.

  Further, in FIG. 1, an area dividing unit 14, a missing region detecting unit 15, and an exposure amount detecting unit 16 are provided on the radiation imaging apparatus 10 side, and an exposure amount comparing unit 21 and apparatus management are provided on the exposure amount management apparatus 20 side. Although the case where the means 22 is provided is illustrated, the radiation dose management apparatus 20 may be built in the radiation imaging apparatus 10, or the area dividing means 14 and the blank area detection means are provided on the exposure dose management apparatus 20 side. 15. An exposure amount detection means 16 may be provided.

DESCRIPTION OF SYMBOLS 1 Radiation imaging management system 2 Network 10 Radiography apparatus 11 Radiation source 12 Radiation detector 13 Imaging control means 14 Area dividing means 15 Element missing area detection means 16 Exposure amount detection means 20 Exposure amount management apparatus 21 Exposure amount comparison means 22 device management means BDR divided exposure dose BR divided region DB database DR detection region P radiographic image S subject TER missing region

Claims (7)

Radiography management for managing the exposure dose by a radiography apparatus that detects radiation transmitted through the subject by a radiation detector when the subject is irradiated with radiation from a radiation source that irradiates the subject. A system,
A blank region detection means for detecting a blank region in which radiation from the radiation source is directly detected without passing through the subject from each divided region when the radiation image is divided into a plurality of regions,
Exposure amount detection means for detecting a divided exposure amount for each of the divided regions using a pixel value of the background loss region detected by the background loss region detection means;
An exposure dose comparison means for comparing the plurality of divided exposure doses detected by the exposure dose detection means;
A radiography management system comprising: an apparatus management unit that manages the radiography apparatus based on a comparison result by the exposure amount comparison unit.   The radiation imaging management system according to claim 1, wherein the apparatus management unit has a function of outputting a warning when a difference between the divided exposure doses is equal to or greater than a set threshold value. The apparatus management means includes data analysis means for calculating statistical data using the divided exposure doses in which a difference between the divided exposure doses is less than a set threshold value. 1 Symbol placement radiography management system of.   The apparatus management means has a function of storing a largest maximum divided exposure amount among the plurality of divided exposure amounts as an exposure amount to the subject at the time of radiography. Item 4. The radiation imaging management system according to any one of Items 1 to 3.   The radiation imaging management system according to claim 1, further comprising region dividing means for setting a divided region of the radiation image.   The radiation imaging management system according to any one of claims 1 to 4, wherein the plurality of divided regions are obtained by dividing the radiation image into strips.   6. The radiation according to claim 1, wherein the radiation imaging apparatus is connected to the plurality of radiation imaging apparatuses via a network so as to be able to transmit data, and manages the plurality of radiation imaging apparatuses. Shooting management system.

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