JP4309103B2 - Radiation dose estimation apparatus and radiation diagnostic apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation dose estimation device for estimating a radiation dose by a radiation diagnostic device and a radiation diagnostic device having the estimation device.
[0002]
[Prior art]
In recent years, examinations using radiation diagnostic apparatuses such as X-ray diagnostic apparatuses and X-ray CT apparatuses have become widespread. The patient must be exposed to radiation to some extent by undergoing the examination by the radiation diagnostic apparatus. However, for example, Japanese Patent Application Laid-Open No. 2000-152924 describes the dose management at that time. The contents are that the dose on the body surface of the patient under examination by the X-ray diagnostic apparatus is displayed, and a warning is issued when the dose reaches a certain value.
[0003]
[Problems to be solved by the invention]
As described above, the management of the exposure dose of the patient by the conventional X-ray diagnostic apparatus is targeted only during the examination. Therefore, the X-ray irradiation amount by the X-ray diagnostic apparatus is not controlled until the patient exposure amount reaches a certain level during the actual examination.
[0004]
In other words, although the operator of the X-ray diagnostic apparatus can confirm the exposure dose, special consideration for the X-ray exposure dose until it is recognized or warned that the exposure dose has reached a certain level, I couldn't have existed unless I was an experienced person. Such a current situation means that a patient is forced to receive a large amount of radiation, and in some cases, the person may be at risk.
[0005]
On the other hand, medical staff including operators at the inspection site usually take measures against exposure by wearing protective apron or protective glasses. However, the current situation is that no measures are taken with respect to the medical staff regarding exposure management for a patient as a subject.
[0006]
Accordingly, an object of the present invention is to provide a radiation dose estimation apparatus and a radiation diagnostic apparatus that can avoid danger related to exposure of a subject or medical staff.
[0007]
[Means for Solving the Problems]
To achieve the above object, the radiation dose estimation apparatus according to claim 1 of the present invention creates first model creation means for creating model information relating to a radiation diagnostic apparatus, and model information including the internal tissue of the subject. Spatial radiation around the radiation diagnostic apparatus based on X-rays emitted from the radiation diagnostic apparatus using the second model creating means and the model information created by the first and second model creating means And an estimation means for estimating the quantity .
[0008]
According to a seventh aspect of the present invention, the radiation diagnostic apparatus of the present invention includes an X-ray generation unit that generates X-rays, an X-ray detection unit that detects X-rays generated by the X-ray generation unit and transmitted through the subject, Estimating means for estimating a spatial radiation dose around the apparatus based on information on the apparatus including at least information on the X-ray generating means and information on a subject irradiated with X-rays by the X-ray generating means; And a display means for displaying the radiation dose estimated by the estimation means.
[0009]
According to the present invention as described above, since the radiation dose can be estimated before or during the examination, it is possible to avoid the danger associated with the exposure of the subject or the medical staff and improve the safety of the examination by the radiation diagnostic apparatus. can do.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, the outline of the embodiment of the present invention will be described with reference to FIGS.
[0011]
FIG. 1 is a schematic diagram showing a flow of operation in the embodiment of the present invention. As shown in the figure, while creating the patient model 12 based on the patient information 11, the X-ray diagnostic apparatus model is also created 14 based on the information 13 related to the X-ray diagnostic apparatus. A calculation 15 of the patient radiation dose and the spatial radiation dose distribution around the patient and the X-ray diagnostic apparatus when the subject based on the patient model is examined under the condition based on the X-ray diagnostic apparatus model is performed. Based on the calculated result, display 16 of the dose distribution is performed.
[0012]
FIG. 2 is a configuration diagram according to the X-ray diagnostic apparatus for explaining the embodiment of the present invention.
[0013]
The patient information 11 described with reference to FIG. 1 is acquired from the radiology department or hospital information system 22 or taken into the radiation dose estimation unit 23 by manual input by a medical staff or the like, and the patient model creation 12 is performed.
[0014]
On the other hand, the X-ray apparatus information 13 is fetched from the X-ray diagnostic apparatus 20 into the radiation dose estimation unit 23, and the X-ray diagnostic apparatus model creation 14 is performed.
[0015]
After the creation of each model, the radiation dose estimation unit 23 calculates the radiation trajectory, the radiation dose to be exposed to the patient 21, and the spatial radiation dose distribution 15 around the patient 21 and the X-ray diagnostic apparatus 20. The result obtained by the radiation dose estimation unit 23, that is, the display 16 of the dose distribution is performed on the display unit 24 such as a monitor.
[0016]
The above is the outline in the embodiment of the present invention. Hereinafter, each item will be described in detail.
(First embodiment)
A first embodiment of the radiation dose estimation apparatus of the present invention will be described below with reference to FIGS.
[0017]
The first embodiment of the present invention estimates the amount of radiation produced under the same conditions, assuming the inspection conditions that would actually be performed before the inspection in the X-ray diagnostic apparatus 20. It is.
[0018]
[Information used for calculation]
First, information necessary for the radiation dose estimation unit 23 in this embodiment to operate will be described. This necessary information is roughly divided into two types, one of which is information on the X-ray diagnostic apparatus 20 that will be used in performing the examination. The other is information relating to a patient (subject) 21 who is scheduled to undergo an examination (assumed to actually undergo the examination). The information of the X-ray diagnostic apparatus 20 is various information related to X-ray irradiation assumed in an actual examination, and will be described in detail below together with information about the patient 21.
[0019]
<Information of X-ray diagnostic equipment>
The information of the X-ray diagnostic apparatus 20 is classified into two types, one is information that is input in advance, and the other is information that is input according to the examination conditions.
[0020]
(Information to be entered in advance)
The information that is input in advance (the description relating to the input will be described later) is information on the shape and material of the apparatus that is unique to the apparatus regardless of the conditions for each inspection. Since the X-ray diagnostic apparatus is composed of a plurality of components, information on each part that affects X-ray irradiation is required.
[0021]
Specifically, an X-ray tube 201 that generates X-rays, an X-ray filter 202 that filters X-rays (but fixed), a collimator 203 that narrows an X-ray irradiation field, and an irradiation X shown in FIG. Information on apparatus shape, material, and arrangement of X-ray monitor 204 for monitoring dose, bed 205, X-ray grid 206 for reducing X-ray scattering, X-ray detector 207, support 208, etc., and standard This is installation information to be set at the time of installation, such as the analog gain, digital gain, X-ray tube voltage, X-ray tube current, and X-ray pulse width of the X-ray detector 207 for the subject.
[0022]
(Information to be entered for each inspection)
The information to be input for each examination (the description relating to the input will be described later) is information in which the setting conditions of the components related to X-ray irradiation of the X-ray diagnostic apparatus 20 change for each examination according to the contents of the examination. Here, prior to each actual inspection, conditions (information) that will be used in the actual inspection are assumed, and the conditions (information) (conditions (information) that are to be set for the actual inspection in some cases) Will be entered by the medical staff.
[0023]
Specifically, various X-ray conditions (tube voltage, tube current, pulse width, pulse rate, X-ray filter (if not fixed)), collimator opening information, (bed position, supporter position) X-ray incident angle , Information on the distance between the X-ray tube and the patient (or the detector).
[0024]
In addition, when the conditions used in the past actual examination and the conditions used in the examination about other patients are stored, these information should be selected and input from these conditions. Also good.
[0025]
<Patient information>
The information of the patient 21 is also classified into two, one is information related to the individual patient, and the other is patient position information.
[0026]
(Information about individual patients)
Examples of the information related to the individual patient include height, weight, body fat percentage, chest circumference, waist circumference, sex, and other information indicating the body type (physique) of the patient 21. It also contains information that can identify the organ position. These pieces of information may be input by the medical staff based on the assumed patient 21 (or the patient who is actually scheduled for the examination). If the examination has been accepted immediately before the actual examination, the necessary information can be obtained from the acceptance information. If the patient 21 to be examined has been accepted at the hospital, the necessary information can be obtained from other systems 22 in the hospital such as the hospital information system. You may make it receive all or one part electronically.
[0027]
(Patient location information)
The patient position information is information indicating what positional relationship the patient 21 has with respect to the X-ray diagnostic apparatus 20.
[0028]
If the position of the patient 21 on the bed 205 is confirmed using a patient monitoring TV camera immediately before the actual examination, the position information may be input by the medical staff. Alternatively, the position information may be taken into the radiation dose estimation unit 23 as electronic information.
[0029]
In addition, when the actual position information as described above cannot be obtained, not just before the examination, the position of the patient 21 is assumed, and the assumed information is input by the medical staff.
[0030]
[Model creation]
When the above-described various information is prepared, models of the X-ray diagnostic apparatus 20 and the patient 21 are created based on the information. Here, the “model” is not limited to a visible virtual object by two-dimensional representation or three-dimensional representation when actually displayed on the display unit 25, but may be any collection of data necessary for modeling as information. Good.
[0031]
In addition, the model creation for the X-ray diagnostic apparatus and the model creation for the patient may be realized by physically different means, or by physically having each creation function in one means (for example, by software) ) May be realized.
[0032]
<X-ray diagnostic equipment model>
As a model of the X-ray diagnostic apparatus 20, according to the above-mentioned <Information of the X-ray diagnostic apparatus>, the X-ray generation location, the generation intensity distribution at the generation location, the X-ray direction, the intensity, the spectrum distribution, the generation time, and The model creation 14 of the X-ray diagnostic apparatus is performed by collecting the X-ray absorption / scattering characteristics, the distance between the X-ray generation unit and the patient, and the incident direction of the X-ray with respect to the patient. In model creation, the basic part of the model is created based on the above (information entered in advance), and a typical pattern model based on this basis (for example, depending on the examination type, examination site, patient type, etc.) May be created in advance, and the most similar one typical pattern model may be selected automatically or manually based on the above (information input for each inspection). Note that the model creation method is not limited to the form described here.
[0033]
<Patient model>
The patient model creation 12 is also basically the same as the method described in the above <Model of X-ray diagnostic apparatus>. Here, the position and size of each organ in the body are determined from the external shape information indicating what type of body the patient 21 is. By using known information such as what kind of substance each organ is made of, the elements that make up that substance, its composition ratio, density, etc. Substance information is mapped. With this information, the trajectory of radiation inside the human body can be traced, and the X-ray absorbed dose can be calculated for each organ. An information patient model is created in three dimensions (or two dimensions) or as a collection of the above information (raw information / processed information) based on the above (information on individual patient).
[0034]
In the model creation, an arbitrary basic model may be created in advance, and an appropriate part may be enlarged or reduced based on the above (information on the patient individual) with respect to the basic model. With regard to the enlargement / reduction, one enlargement / reduction ratio that is the closest to the patient 21 may be selected, or the enlargement / reduction ratio may be selected for each part.
[0035]
As another method, a plurality of body type pattern models (for example, sex, age, type, etc.) are prepared in advance, and one of the most similar body type pattern models based on the above (information on individual patient) May be selected. Note that the model creation method is not limited to the form described here.
[0036]
FIG. 3 is a diagram illustrating the above description of the patient model creation 12. Based on the patient information 31, the patient model creation unit 32 performs scaling (scaling) of the basic model (322), or by selecting the most appropriate one from the body pattern model (321), the patient model 33 is Will be created.
[0037]
[Calculation of radiation locus and radiation dose]
<Calculation of radiation trajectory>
When the above models are created, the locus of radiation is obtained using these created models.
[0038]
In this embodiment, a Monte Carlo calculation known by software EGS4 or the like developed in the field of high energy physics (using a collision cross section representing an interaction between radiation and a substance, and follows the trajectory of each particle of radiation) The radiation trajectory is obtained by calculation. Note that when the radiation dose described later can be calculated without obtaining the radiation trajectory, the computation for obtaining the radiation trajectory is not necessary.
[0039]
In the Monte Carlo calculation, the calculation can be executed for all the X-ray photons generated in the X-ray tube. However, if the statistical accuracy necessary for dose estimation can be obtained, it is not necessary to execute the calculation. For example, in an actual apparatus, even if 1 million X-ray photons are generated, if the required statistical accuracy can be obtained by executing the calculation for 10,000 photons, the calculation is terminated at 10,000. The obtained dose data may be multiplied by 100 to obtain an estimated value. Thereby, the processing time concerning the calculation for obtaining the locus of radiation can be shortened.
[0040]
In actual calculation, the calculation is made based on the value input as <information of X-ray diagnostic apparatus>. First, the generated X-ray spectrum is determined from the tube voltage and the X-ray tube target material. The amount of X-rays generated is determined from the tube current, the X-ray pulse width, and the pulse rate. The X-ray tube specific filtration and the X-ray filter 202 are used for locus calculation as a substance that transmits the generated X-rays. The X-rays that have passed through the X-ray filter 202 are absorbed and scattered by the collimator 203, and then absorbed and scattered by the air and reach the patient body surface.
[0041]
By the way, the X-rays that have reached the surface of the patient are absorbed and scattered within the patient and give exposure to each part of the body. X-rays transmitted through the patient 21 are absorbed and scattered by the bed 205, the X-ray grid 206, and the X-ray detector 207. The scattered X-rays may enter the patient 21 again. In the present invention, such re-incident X-rays are also subject to calculation.
[0042]
<Calculation of radiation dose>
When the radiation trajectory is obtained by the method described in <Calculation of radiation trajectory>, the unit volume at each position in the whole space (inside / outside of the patient and the space around the apparatus) to be calculated from the trajectory. The number of incident particles of radiation and the energy absorbed are known.
[0043]
By the way, the following doses are defined as radiation doses.
・ Irradiation dose (E): Index of ionization ability to air 1R = 2.58 × 10 ⁻⁴ C / kg
Air absorbed dose (G): index of energy absorbed by air Gy = J / kg = 8.7 × 10 −3 × E (R) (1)
・ Absorbed dose (D): Energy given to mass J / kg
-Tissue absorbed dose (D _T ): Average value of absorbed dose over tissue In the above, irradiation dose and air absorbed dose are suitable as an index of air dose (dose in the space around the device), and absorbed dose and tissue The absorbed dose is suitable as an index of the exposure dose in the patient. These doses can be calculated according to the definition of each dose from the calculation result of the radiation trajectory.
[0044]
FIG. 4 is a diagram showing a conversion relationship to an irradiation dose when one X-ray photon having a certain energy is incident on a unit area in the air. The air absorbed dose can be obtained using the formula (1) based on the irradiation dose. On the other hand, the absorbed dose in the patient can be obtained as a difference between the energy of the radiation incident into the minute volume and the emitted radiation. Thus, the tissue absorbed dose can be calculated by averaging the absorbed dose within the same tissue defined in the patient model.
[0045]
<Display of radiation trajectory>
Next, display of the obtained radiation locus will be described. The radiation trajectory obtained by the Monte Carlo calculation or the like is displayed in a manner as shown in FIGS.
[0046]
FIG. 5 is a diagram showing trajectories of various kinds of radiation estimated to be generated under the conditions based on the <information on X-ray diagnostic apparatus> and the <patient information>.
[0047]
In the figure, a thick solid line indicates X-rays, a thin solid line indicates characteristic X-rays, and a dotted line indicates electrons. There are two types of X-rays depending on the generation process. There are X-rays called bremsstrahlung X-rays generated using bremsstrahlung and characteristic X-rays.
Characteristic X-rays are monochromatic X-rays having energy specific to a substance (element), and this X-ray is excited when atoms in the substance are excited by radiation (including X-rays) incident on the substance. It is released in the process where
[0048]
Next, FIG. 6 is a diagram showing an example of displaying the transition of the radiation trajectory. It shows the state of the radiation generated over time, and the trajectory displayed for a certain period of time fades out with the passage of time (dotted line on the drawing), while the newly generated radiation trajectory (solid line on the drawing) is displayed. The That is, as shown in FIG. 6, the first screen starts from the first screen in FIG. 6A, and after a certain time, the trajectory displayed on the first screen fades out and a new trajectory is displayed in FIG. ) Is displayed as shown on the second screen. Similarly, the second screen is switched to the third screen (FIG. 5C) as a certain time elapses.
[0049]
FIG. 7 shows a three-dimensional space including a patient, a medical staff, and an X-ray diagnostic apparatus at an arbitrary viewpoint (in the drawing, the patient's body side (the figure (a)), the patient's head (the figure (b)), And the case where the radiation locus | trajectory at the time of seeing from the patient front (examination room ceiling) (the figure 3 (c)) view is shown is shown. The viewpoints are not limited to these three viewpoints, and other medical staff may arbitrarily select them. If the number of display monitors is one, the trajectory from each viewpoint may be switched and displayed. If a plurality of monitors are provided, the trajectory from each viewpoint is simultaneously displayed on a plurality of monitors. May be. By displaying simultaneously, it becomes easier to grasp the state of radiation scattering in three dimensions.
[0050]
The X-rays, characteristic X-rays, and electron radiation trajectories in each display example may be displayed in different colors in addition to being distinguished by thick solid lines, thin solid lines, dotted lines, and the like.
[0051]
<Indication of radiation dose>
8 to 11 are display examples of the estimated radiation dose in the embodiment of the present invention.
(Space radiation dose display)
FIG. 8 is a diagram illustrating an example of displaying the spatial radiation dose. The figure (a) is an example of a cross-section designation screen. The medical staff wants to know an arbitrary cross-section (for example, spatial radiation dose) for a three-dimensionally displayed space around the X-ray diagnostic apparatus including the patient. The cross section with respect to the space (the cross sections A, B, and C in FIG. 8A) can be designated.
[0052]
When a cross section is designated in FIG. 8A, the radiation dose in the spatial plane corresponding to the designated cross section is calculated by the above-described calculation method. FIG. 8B is an example of a screen that displays the radiation dose for the cross section designated in FIG. 8A, and the spatial radiation dose calculated for the designated cross section is displayed together with the patient and the X-ray diagnostic apparatus in each cross section. Is done. At that time, grayscale gradation display is performed according to the radiation dose concentration. By this gray level display, it is possible to easily determine which position or region in the space (cross section) has a high radiation concentration, that is, whether the exposure radiation dose is large and dangerous.
[0053]
For this reason, the medical staff can grasp | ascertain beforehand the space which should avoid entering more than necessary in an actual test | inspection.
(Display patient exposure dose)
Next, FIG. 9 is a diagram showing an example of displaying the radiation dose exposed in the patient. FIG. 9A shows an example of a cross-section designation screen. For a patient displayed three-dimensionally, the medical staff can select an arbitrary cross-section (for example, a cross-section for a site for which the exposure dose is desired) (FIG. 9A). Then, sections A, B, and C) can be designated.
[0054]
When the cross section is designated in FIG. 9A, the absorbed radiation dose in the patient corresponding to the designated cross section is calculated by the above-described calculation method. FIG. 9B is an example of a screen that displays the radiation dose for the cross section designated in FIG. 9A, and the radiation dose within the patient calculated for the designated cross section is displayed together with the patient in each cross section. . At that time, grayscale gradation display is performed according to the radiation dose concentration. By this gray level display, it is possible to easily determine which part (which organ, which body surface) in the patient's body has a high radiation concentration, that is, whether the radiation dose is large.
[0055]
For this reason, it becomes possible to take measures against exposure in advance, such as lowering the X-ray irradiation dose to a necessary minimum level in actual inspection.
[0056]
In addition, the radiation dose concentration display may be color-coded display using a color scale instead of the gray scale in both the spatial radiation dose display and the patient internal radiation dose display.
[0057]
The patient or X-ray diagnostic apparatus displayed at the same time when the radiation dose is displayed may be an image obtained by photographing an actual patient or X-ray diagnostic apparatus, or based on the information on the patient model or apparatus model described above. It may be anything such as a general composite image that is completely created independently of the actual device or patient information.
(Internal patient tissue absorbed dose display)
The above (in-patient exposure dose display) is an example of displaying the radiation dose in a specific cross section of the patient. In the present invention, the absorbed dose in the tissue (organ) in the patient may also be calculated and displayed. In this case, the tissue may be displayed three-dimensionally as shown in FIG. 9 and the concentration may be displayed using a galley scale or a color scale, or the absorbed dose may be displayed as a list as shown in FIG. Also good.
[0058]
FIG. 10 is a diagram showing an example of displaying a list of estimated absorbed doses for patient body tissues. In the figure, the estimated absorbed dose in each of the lens, heart, and liver is listed. Moreover, by setting a ROI (Region of Interest) (region of interest) on the skin by specifying a cross section, the absorbed dose in the skin in the region can also be estimated, and the estimated value of the skin absorbed dose in each ROI is also calculated. List display is possible. Regarding the absorbed skin dose, not only the X-ray dose by X-ray irradiation from the outside of the body but also the radiation reflected in the body is absorbed by the patient's body surface as the absorbed skin dose, so far known. It becomes possible to show a more accurate value than the absorbed skin dose calculated from the X-ray irradiation dose and the distance to the patient.
(Warning display)
By setting the allowable radiation dose for each site in the patient in advance, a warning is given when the estimated radiation dose exceeds this allowable value. The warning may be a sound (voice) or a display warning on the monitor.
[0059]
Regarding the setting of the allowable radiation exposure dose, a generally determined value may be set and registered in advance for each part (or for each part for each patient model) as a default value, or by a doctor for each patient. Different allowable values may be set and changed individually.
[0060]
FIG. 11 is a diagram showing a display example of a screen for setting / changing the allowable exposure radiation dose. In the same figure, the case where the allowable value of each part corresponding to the estimated absorbed dose shown in FIG. 10 is set / changed is shown.
[0061]
By setting an allowable exposure radiation dose and issuing a warning when it exceeds that value, if the warning is received at the estimated amount before the inspection as in this embodiment, it is actually In this examination, it can be determined in advance that there is a problem in proceeding with the examination as it is (in terms of the radiation dose to the patient). In other words, by knowing in advance that there is a possibility that the patient's radiation dose may exceed the allowable value, such as reviewing the plan in the actual examination, reducing the X-ray irradiation dose to the minimum necessary level, It is possible to take measures against exposure in advance.
[0062]
As described above, according to the first embodiment of the present invention, it is shown in FIG. 12 showing the relationship between the radiation dose estimation in the actual examination according to the present embodiment and the second embodiment. As described above, it is assumed that the conditions of the inspection that will be actually performed before the actual inspection, that is, the patient information to be inspected, the apparatus information of the X-ray diagnostic apparatus, and the setting conditions at the time of the inspection of the apparatus, etc. It is possible to estimate how much radiation is produced under the conditions.
[0063]
In other words, by feeding this result back to the actual examination plan, it is possible to make a plan in advance to avoid the risk that the patient will exceed the allowable exposure radiation dose in the actual examination. In addition, since the amount of space radiation around the patient and the X-ray diagnostic equipment can be grasped, the area to be avoided by the medical staff as much as possible in the actual examination can be grasped in advance. It is possible to avoid exposure.
(Second Embodiment)
The left half of FIG. 12 shows an example according to the first embodiment of the present invention, but the second embodiment of the present invention is a portion corresponding to the right half of FIG. A case where the radiation dose in the examination is estimated and grasped in real time will be described.
[0064]
First, the operation of the X-ray diagnostic apparatus will be described with reference to FIG. 2 briefly described in the first embodiment.
[0065]
In the X-ray diagnostic apparatus 20 shown in the figure, the X-ray generated by the X-ray tube 201 is filtered by the X-ray filter 202, and the solid angle of the X-ray that can reach the subsequent X-ray detector 207 by the collimator 203 is limited. The The X-ray monitor 204 can monitor the amount of X-rays focused on the patient 21 by the collimator 203. X-rays transmitted through the patient 21 sleeping on the bed 205 are also detected by the X-ray detector 207 via the X-ray grid 206 after passing through the bed 205. By providing the X-ray grid 206, the influence of scattered radiation is reduced, so that the contrast of the image detected by the X-ray detector 207 is improved. Note that the bed 205 (X-ray grid 206, X-ray detector 207) is moved up and down by the support 208 according to the necessity of inspection. Further, the bed 205 is further moved horizontally back and forth and left and right according to the necessity of inspection.
[0066]
In the second embodiment of the present invention, in order to estimate the radiation dose in the actual examination, the information of the X-ray diagnostic apparatus 20 and the information of the patient 21 are necessary as in the case of the first embodiment. It is.
[0067]
<Information of X-ray diagnostic equipment>
The information of the X-ray diagnostic apparatus 20 is classified into two types, one is information that is input in advance, and the other is information that is input according to the examination conditions.
[0068]
(Information to be entered in advance)
Basically, this is the same as in the first embodiment.
[0069]
The information that is input in advance is information relating to the shape and material of the apparatus as unique to the apparatus regardless of the conditions for each inspection. Since the X-ray diagnostic apparatus 20 is composed of a plurality of components, information on each part that affects X-ray irradiation is required.
[0070]
Specifically, an X-ray tube 201 that generates X-rays, an X-ray filter 202 that filters X-rays (but fixed), a collimator 203 that narrows an X-ray irradiation field, and an irradiation X shown in FIG. Information on the apparatus shape and material of the X-ray monitor 204 for monitoring the dose, the bed 205, the X-ray grid 206 for reducing X-ray scattering, the X-ray detector 207, the support 208, and the like, and further the X-ray detector 207 Installation information to be set at the time of installation, such as analog gain, digital gain, X-ray tube voltage, X-ray tube current, and X-ray pulse width.
[0071]
(Information to be entered for each inspection)
The information is the same as in the first embodiment, but in the second embodiment, information related to the actual inspection is input.
[0072]
The information input for each examination is information in which the setting conditions of the components related to the X-ray irradiation of the X-ray diagnostic apparatus 20 change for each examination according to the contents of the examination. In fact, the following pieces of information can be automatically taken into the radiation dose estimation unit 23 automatically from the X-ray diagnostic apparatus 20. When it cannot be automatically captured (information that cannot be automatically captured), it is input by the medical staff at any time.
[0073]
Specifically, various X-ray conditions (tube voltage, tube current, pulse width, pulse rate, X-ray filter (if not fixed)), collimator opening information, (bed position, supporter position) X-ray incident angle , Information on the distance between the X-ray tube and the patient (or the detector).
[0074]
<Patient information>
The information of the patient 21 is also classified into two, one is information related to the individual patient, and the other is patient position information.
[0075]
(Information about individual patients)
The information is the same as in the first embodiment.
[0076]
Examples of the information related to the individual patient include height, weight, body fat percentage, chest circumference, waist circumference, sex, and other information indicating the body type (physique) of the patient 21. It also contains information that can identify the organ position. These pieces of information may be input by the medical staff based on the patient 21 who is actually scheduled for the examination. Note that all or part of necessary information may be electronically received from the examination reception information or from another system 22 in the hospital such as a hospital information system.
[0077]
(Patient location information)
The patient position information is information indicating what positional relationship the patient 21 has with respect to the X-ray diagnostic apparatus 20.
[0078]
In the second embodiment, information in an actual inspection is input.
[0079]
FIG. 13 is a diagram showing an example of determining the positional relationship between the patient and the X-ray diagnostic apparatus.
[0080]
As shown in the figure, the relative positional relationship between the patient and the X-ray diagnostic apparatus can be obtained from two pieces of information.
(1) Rough position of the entire patient The human body is recognized based on the patient's TV camera image taken using the patient monitoring TV camera, and the position information of the bed at that time is acquired based on the bed control information. . From these pieces of information, a rough positional relationship between the entire human body of the patient and the X-ray diagnostic apparatus can be obtained, and this is replaced with a positional relationship between a patient model and an X-ray diagnostic apparatus model, which will be described later.
(2) Patient local position The human body is recognized by obtaining a fluoroscopic image / photographed image immediately after the actual examination starts, and the position information of the bed at that time is acquired based on the bed control information. From these pieces of information, a rough positional relationship between the local area of the human body (such as an organ) and the X-ray diagnostic apparatus can be obtained, and this is replaced with the positional relationship between the patient model and the X-ray diagnostic apparatus model described later.
[0081]
From the information of (1) and (2) above, it is possible to obtain patient position information with respect to the X-ray diagnostic apparatus using the patient model and the X-ray diagnostic apparatus model.
[0082]
The patient position information is initially obtained based on information immediately after the start of the examination. However, if the patient moves with respect to the apparatus during the examination, the position of the patient can be obtained by performing the above (1) and (2) as needed. Information may be updated in real time. In this way, it is possible to estimate the radiation dose and the spatial radiation dose of the patient more accurately.
[0083]
Not only patient position information but also device information may be updated in real time in real time. That is, as described in the description of FIG. 2, for example, there is a setting according to the necessity during the inspection, such as the vertical and horizontal movement of the bed 205, the irradiation dose in the X-ray tube 201, or the X-ray filter. By capturing the information as needed, it is possible to estimate the radiation dose and the spatial radiation dose of the patient more accurately.
[0084]
Note that the irradiation dose from the X-ray tube 201 can be corrected at any time using this result because the system having the X-ray monitor 204 can know the actual irradiation X-ray dose through the collimator 203. Is possible.
[0085]
FIG. 14 is a schematic diagram showing a flow of operation in the present embodiment. As shown in the figure, the patient model generation 146 is performed based on the patient personal information 141 and the patient position information 142 that may change at the time of the examination, while the installation information and the like are input in advance as information of the X-ray diagnostic apparatus. The X-ray diagnostic apparatus model generation 147 is also performed based on the information 143 to be performed and the information 144 for each examination that may change during the examination. The patient position information 142 is updated in real time. In addition, the information 144 for each examination of the X-ray diagnostic apparatus also changes as the X-ray diagnostic apparatus 145 updates in real time.
[0086]
Based on the information relating to the actual examination, calculation 148 of the patient radiation dose estimated by modeling the X-ray diagnostic apparatus and the patient and the spatial radiation dose distribution around the patient and the X-ray diagnostic apparatus is performed. Based on the calculated result, the dose distribution display 149 is performed.
[0087]
Note that [model creation] [calculation of radiation trajectory / radiation dose] is the same as that described in the first embodiment, and therefore description thereof is omitted here.
(Display format)
FIG. 15 is a diagram showing an example of a display form of the display unit 24 during the examination.
[0088]
As shown in the figure, when the display unit 24 is used in a two-monitor format or in a form in which two windows are displayed side by side, a real-time (instantaneous) radiation dose is displayed on one (for example, the left side) display frame. You may make it display the integral value of the radiation dose until then on the other (for example, right side) display frame. As specific display information, for example, a spatial radiation dose around the patient or the X-ray diagnostic apparatus and / or an exposed radiation dose on the patient's skin can be considered as a real-time display (display examples: FIGS. 8 and 9). Further, as an example of the integral value display, exposure radiation dose in an organ or tissue in a patient can be considered (display examples: FIGS. 9 and 10).
[0089]
FIG. 16 is a diagram showing an example of another display form of the display unit 24 during the examination. The example shown in the figure is a case where the display unit 24 is displayed in one monitor format or in one window by switching display contents during X-ray irradiation and non-X-ray irradiation.
[0090]
FIG. 15A shows the case where the contents shown as the display example in the left display frame in FIG. 15 are displayed. While X-rays are being emitted, real-time display of the radiation dose related to the irradiated X-rays is performed. Is what you do. The display content is a spatial radiation dose around the patient or the X-ray diagnostic apparatus and / or an exposure radiation dose on the patient's skin.
[0091]
FIG. 15B shows a case where the content shown as the display example in the right display frame in FIG. 15 is displayed, and displays the integrated value of the radiation dose until then when X-rays are not irradiated. It is. The displayed content is the radiation dose in the organ or tissue in the patient. In this way, even when the display unit 24 cannot display two monitors (two windows), a sufficiently effective display can be performed.
[0092]
Although the radiation dose display form is shown in FIGS. 15 and 16 as the second embodiment of the present invention, actually, the locus calculation of the radiation and the calculation of the radiation dose usually take time.
[0093]
Accordingly, it may be difficult to calculate the radiation exposure accumulation amount (integrated value) in the patient body including the radiation dose due to the X-ray irradiation while calculating for real-time display during the X-ray irradiation. Therefore, for such a case, the display methods shown in FIGS. 17 and 18 can be considered as examples according to the processing capability of the radiation dose estimation unit.
[0094]
FIG. 17 is a diagram showing, in time series, an example of the relationship between X-ray irradiation, radiation dose display, and radiation dose calculation processing.
[0095]
As shown in the figure, during the X-ray irradiation (on), the spatial radiation dose around the patient and the X-ray diagnostic apparatus and / or the exposure radiation dose on the patient's skin are displayed in real time. During the X-ray irradiation, recording of various conditions in the X-ray diagnostic apparatus and the state transition of the apparatus is performed inside the radiation dose estimation unit (background).
[0096]
When the X-ray irradiation is stopped due to the interruption or termination of the X-ray irradiation (off), the real-time display related to the irradiation ends, and the radiation dose (integrated value) accumulated in the patient's body is displayed. However, immediately after the end of the X-ray irradiation, an integrated value not including the radiation dose due to the X-ray irradiation performed immediately before the end is displayed. In addition, during the integral value display period, in the radiation dose estimation unit (background), based on the various conditions in the X-ray diagnostic apparatus recorded during X-ray irradiation and the transition information of the state of the apparatus, the patient Calculation of the latest radiation trajectory in the body and the amount of radiation dose is calculated. When the calculation is completed, the latest radiation dose (the radiation dose accumulated in the patient) is displayed instead of the integral value being displayed. This display continues until X-ray irradiation is started again.
[0097]
Next, FIG. 18 is a diagram showing in time series another example of the relationship between X-ray irradiation, radiation dose display, and radiation dose calculation processing.
[0098]
As shown in the figure, during the X-ray irradiation (on 1), the spatial radiation dose around the patient and the X-ray diagnostic apparatus and / or the exposure radiation dose on the patient's skin are displayed in real time. During the X-ray irradiation, recording of various conditions in the X-ray diagnostic apparatus and the state transition of the apparatus is performed inside the radiation dose estimation unit (background). At the same time, the radiation dose (integrated value) accumulated in the patient's body is calculated including the radiation dose at the previous X-ray irradiation (however, this time does not include the radiation dose in X-ray irradiation (on1)).
[0099]
When the X-ray irradiation is stopped due to the interruption or termination of the X-ray irradiation (off), the real-time display related to the irradiation ends, and the radiation dose (integrated value) accumulated in the patient's body is displayed. However, the integrated value not including the radiation dose due to the X-ray irradiation (on1) this time is displayed. Further, during the integral value display period, inside the radiation dose estimation unit (background), based on the various conditions in the X-ray diagnostic apparatus recorded during the X-ray irradiation (on1) and the transition information of the state of the apparatus. Thus, the calculation of the latest radiation trajectory in the patient and the radiation dose is calculated. This calculation is continued until the next X-ray irradiation (on2), and is completed by the end of the X-ray irradiation (on2) at the latest. When the calculation is completed, the radiation dose accumulated in the patient is displayed after the end of the X-ray irradiation (on2). This display continues until X-ray irradiation is started again.
(Preservation of estimated radiation dose)
In the present invention, the estimated radiation dose may be stored in a nonvolatile memory or the like. By storing it, it becomes possible to refer to it later or add it to the radiation dose in another examination.
(Application to multiple inspections)
When multiple examinations by the X-ray diagnostic apparatus are performed on the same patient, the estimated radiation dose in the examination prior to the latest examination, particularly the radiation dose accumulated in the patient's body, is saved, Alternatively, the estimated radiation exposure dose (for the same part in each examination) may be added.
[0100]
FIG. 19 is a conceptual diagram showing a case where the radiation doses in the two examinations are added. As shown in the figure, the radiation dose estimation calculation result based on the X-ray diagnostic apparatus information in the examination 1 and the radiation exposure estimation calculation result based on the X-ray diagnostic apparatus information in the examination 2 (at least first) for the same patient. Add (by saving the results of the tests performed) and display the results.
[0101]
By doing in this way, the radiation dose accumulated in the body can be confirmed by the patient undergoing examinations a plurality of times. Depending on the accumulation result, it is also possible to send a notification to the next inspection such as “the exposure is already quite high”. Also, even if you do not send such a request, by confirming the past radiation dose before a new examination, if necessary, that is, if the radiation dose has already reached a certain amount, In this new inspection, it is possible to review the inspection plan in advance, such as reducing the X-ray irradiation dose to the specified minimum.
[0102]
In addition, for a new examination, estimation (simulation) before the examination as described in the first embodiment is performed, and the result and the stored result of the past examination are added and confirmed. It is possible to review the inspection plan for the new inspection before implementation.
[0103]
Therefore, even if the estimated radiation dose does not reach the critical dose that would be a warning target in a single test, it can be judged by the radiation dose combined with the previous exam, so carelessly And the patient can feel confident in the examination.
[0104]
When adding multiple examinations as described above, each examination is not intended for only those performed in a short period of time, but is intended for long-term examinations and managed as exposure history information for the patient. Also good.
[0105]
In addition, although the case where the X-ray diagnostic apparatus was used as an embodiment of the present invention has been described, in the present invention, not only the X-ray diagnostic apparatus but also, for example, an X-ray CT apparatus may be targeted. In addition, regarding addition and comparison of radiation doses in a plurality of examinations, the estimation result obtained by the examination in the X-ray diagnostic apparatus and the estimation result obtained by the examination in the X-ray CT apparatus may be added.
(Radiation dose estimation support service)
The radiation dose estimation according to the present invention described above may be performed as an estimation support service for a third party. That is, it is implemented as a remote service via a network for a facility (examination room, hospital, etc.) that does not have the radiation dose estimation apparatus according to the present invention or the radiation diagnostic apparatus having the radiation dose estimation function. It may be.
[0106]
Examples of the place where the estimation support service is performed include an examination room, a hospital different from the facility, or a facility specializing in the service.
[0107]
In this case, it is assumed that device information such as an X-ray diagnostic apparatus, patient information, and medical staff information are input by a medical staff or the like on the side receiving the estimation support service.
[0108]
The input information is sent via the network to the estimation support service implementation facility having the radiation dose estimation apparatus according to the present invention. In the radiation dose estimation apparatus, a radiation trajectory and various radiation doses are calculated based on information received via a network. The obtained calculation result or the display content based on the result is transmitted again to the request source via the network.
[0109]
On the side receiving the estimation support service, it is possible to obtain the same effect as in the case of having the radiation dose estimation apparatus according to the present invention.
[0110]
This estimation support service can be received not only during the pre-inspection but also during the inspection. In particular, if the requesting facility and the service providing facility are different laboratories in the same hospital, there is a high possibility that they are connected to a common LAN. If they are connected, even if there is a slight time difference, the benefits of this estimation support service can be enjoyed with little practical problem.
[0111]
As described above, according to the present invention, at the stage of an examination plan before an actual examination by the radiation diagnostic apparatus, the radiation dose of the patient (particularly the patient's body), the spatial radiation dose around the patient / radiological diagnosis apparatus, and the spatial radiation dose. Since the risk of exposure of medical staff can be estimated, it becomes possible to review the inspection plan before conducting the actual inspection.
[0112]
In addition, during the actual examination, the radiation dose of the patient (especially in the patient's body) and the spatial radiation dose around the patient / radiological diagnosis device are estimated and displayed as the amount of change and accumulation of the radiation increases as the examination time passes. As the patient's body position changes and the examination environment changes every moment, the patient's radiation dose can be taken into consideration during the examination. The present invention has an effect that it is possible to grasp a place where the entry is dangerous (the concentration of the spatial radiation dose is high).
[0113]
【The invention's effect】
According to the present invention, by displaying by estimating the spatial radiation dose near the device, it is possible to improve the possibility allowed, safety inspection by radiodiagnostic device risk aversion regarding exposure of the subject or medical staff .
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a flow of operations in an embodiment of the present invention.
FIG. 2 is a configuration diagram relating to an X-ray diagnostic apparatus for explaining an embodiment of the present invention.
FIG. 3 is a view for explaining patient model creation according to the embodiment of the present invention;
FIG. 4 is a diagram showing an X-ray photon / irradiation dose conversion relationship according to the embodiment of the present invention.
FIG. 5 is a view showing a locus of radiation related to X-ray irradiation according to the embodiment of the present invention.
FIG. 6 is a view showing a transition display example of a radiation locus according to the embodiment of the present invention.
FIG. 7 is a view showing a display example of a radiation locus viewed from an arbitrary viewpoint in the three-dimensional space according to the embodiment of the present invention.
FIG. 8 is a view showing a display example of a spatial radiation dose with respect to a selected cross section according to the embodiment of the present invention.
FIG. 9 is a view showing a display example of an exposure radiation dose in a patient with respect to a selected section according to the embodiment of the present invention.
FIG. 10 is a view showing a list display example of an estimated absorbed dose of a patient body tissue according to the embodiment of the present invention.
FIG. 11 is a view showing a display example of a screen for setting / changing the allowable exposure radiation dose of the patient body tissue according to the embodiment of the present invention.
FIG. 12 is a diagram showing a relationship of radiation dose estimation before and after the examination according to the embodiment of the present invention.
FIG. 13 is a diagram showing an example of determining the positional relationship between a patient and an X-ray diagnostic apparatus according to an embodiment of the present invention.
FIG. 14 is a schematic diagram showing a flow of another operation in the present embodiment.
FIG. 15 is a diagram showing an example of a display form during an inspection according to the embodiment of the present invention.
FIG. 16 is a diagram showing another example of the display form during the inspection according to the embodiment of the present invention.
FIG. 17 is a diagram showing an example of the relationship of X-ray irradiation / display / calculation processing according to an embodiment of the present invention in time series.
FIG. 18 is a diagram showing another example of the relationship of X-ray irradiation / display / calculation processing according to the embodiment of the present invention in time series.
FIG. 19 is a conceptual diagram showing addition of radiation doses for a plurality of examinations according to an embodiment of the present invention.
[Explanation of symbols]
11, 31 ... Patient information 12, 146 ... Creation of patient model 13 ... Information related to X-ray diagnostic apparatus 14, 147 ... Creation of X-ray diagnostic apparatus model 15, 148 ... Patient Calculation of exposure radiation dose and spatial radiation dose distribution around patient and X-ray diagnostic apparatus 15
16, 149 ... Dose distribution display 20, 145 ... X-ray diagnostic apparatus 21 ... Patient 22 ... Radiology or hospital information system 23 ... Radiation dose estimation unit 24 ... Display unit 32 ... Patient model creation unit 33 ... Patient model 141 ... Patient personal information 142 ... Patient position information 143 ... Information 144 input in advance as information of the X-ray diagnostic apparatus ... X-ray Information for each examination of diagnostic equipment

Claims (7)

First model creating means for creating model information relating to the radiation diagnostic apparatus;
A second model creating means for creating model information including the internal tissue of the subject;
Estimating means for estimating a spatial radiation dose around the radiation diagnostic apparatus based on X-rays irradiated by the radiation diagnostic apparatus using model information created by the first and second model creating means; A radiation dose estimation apparatus characterized by:   The radiation dose estimation apparatus according to claim 1, further comprising display means for displaying the radiation dose estimated by the estimation means.   The apparatus further comprises means for obtaining a radiation locus by X-ray irradiation using the model information created by the first and second model creation means, and the display means also displays the radiation locus. Item 3. The radiation dose estimation apparatus according to Item 2.   The radiation dose estimation apparatus according to claim 1, further comprising transmission means for transmitting the radiation dose estimated by the estimation means to the outside via a network. The radiation dose estimation apparatus according to any one of claims 1 to 4 , wherein the first model creation means creates model information related to a radiation diagnostic apparatus assumed before an actual examination. The radiation dose estimation apparatus according to any one of claims 1 to 4 , wherein the second model creation means creates model information related to a subject assumed before an actual examination. X-ray generation means for generating X-rays;
X-ray detection means for detecting X-rays generated by the X-ray generation means and transmitted through the subject;
Estimating means for estimating a spatial radiation dose around the apparatus based on information on the apparatus including at least information on the X-ray generating means and information on a subject irradiated with X-rays by the X-ray generating means;
A radiation diagnostic apparatus comprising: a display unit configured to display a radiation dose estimated by the estimation unit.

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