JP4950461B2 - Irradiation dose abnormality analyzer and irradiation dose abnormality analysis program - Google Patents

Description

  The present invention relates to an irradiation dose abnormality analysis apparatus and an irradiation dose abnormality analysis program for analyzing an abnormality of radiation irradiation dose in a medical device using radiation.

  Although using X-rays for the diagnosis or treatment of patients is still a useful method at present, it is inevitable that patients receive X-rays with the diagnosis. Therefore, the amount of X-ray irradiation (X-ray exposure) to a patient is an important issue for diagnostic diagnosis and treatment of X-rays, and is also an important concern for users (doctors, laboratory technicians, etc.). is there.

  An X-ray management apparatus that predicts and manages such an X-ray exposure amount based on inspection plan data is known.

  On the other hand, there is a service that distributes examination information of medical diagnostic apparatuses such as an X-ray CT apparatus to users as reports. In this type of service, information for helping to improve the inspection efficiency based on the inspection information and information for maintaining the quality of the diagnostic apparatus are sent to the user.

  In hospitals that perform X-ray diagnosis and treatment, there is an obligation to manage the X-ray exposure amount for safe examination, and it is checked whether an exceptional value such as an abnormally large X-ray exposure amount has occurred. Or change parameter settings so that inspection can be done with a small amount of X-rays. In addition, if an exceptional value has occurred, it is necessary to improve the parameters by pursuing the cause in order to prevent recurrence.

  However, since a system and service for assisting in managing the X-ray exposure dose have not been established in the past, it has been very difficult for the user to manage the X-ray exposure dose.

  As is well known, the environment surrounding hospital management has become increasingly severe. In particular, in the radiology department that introduces diagnostic imaging equipment and provides image information and diagnostic report information, device performance information, such as the operating status and usage status of diagnostic imaging equipment, is analyzed to improve the efficiency of radiation department management. Effective use of diagnostic equipment is an important management issue.

  There is also a need to provide an environment that can fully exploit the performance of expensive diagnostic imaging apparatuses and that can be used in a safe and reliable state. In particular, it goes without saying that the device utilization protocol is an important element in acquiring clinical images.

  However, since diagnostic imaging devices are used in various diseases and diagnostic areas such as cardiovascular, digestive organs, and brain surgery, the types and amounts of required images are very different. It is necessary to provide images according to the requirements. That is, it is required to provide an inspection protocol according to each user's problem and problem.

On the other hand, in order to manage the exposure dose, there is also a proposal to find an inspection or protocol with an abnormally large exposure dose and use it for business improvement.
JP-A-4-295172 JP 2003-271748 A

  However, depending on the various techniques as described above, it is only possible to know which inspection has an abnormally high irradiation dose, and it has not been understood why.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to enable the user to recognize the cause of the increased irradiation dose.

In order to achieve the above object , the present invention includes an irradiation dose related to an inspection performed by a medical inspection apparatus that performs an inspection by irradiating a subject with radiation, and first and second parameters different from the irradiation dose. In an irradiation dose abnormality analyzer that can access a database for registering a plurality of examination information for each of the plurality of examinations, a threshold value determined according to a distribution of irradiation doses included in each of the plurality of examination information registered in the database An extraction means for extracting inspection information including a large irradiation dose from the plurality of inspection information registered in the database as abnormal inspection information, and for each of the abnormal inspection information extracted by the extraction means, A first model representing the relationship between the irradiation dose included in the examination information and each of the first and second parameters. And a creation means for creating a presentation information including beauty second graph.

In order to achieve the above object, another aspect of the present invention provides an irradiation dose related to an inspection performed by a medical inspection apparatus that performs an inspection by irradiating a subject with radiation, and first and second parameters different from the irradiation dose. A computer capable of accessing a database for registering a plurality of examination information including a plurality of examination information larger than a threshold value determined according to a distribution of irradiation doses included in each of the plurality of examination information registered in the database Extraction means for extracting inspection information including irradiation dose from the plurality of inspection information registered in the database as abnormal inspection information, and abnormal inspection information for each of the abnormal inspection information extracted by the extraction means First and second representing the relationship between the irradiation dose contained in the first and second parameters, respectively. And to function as creating means for creating a presentation information including the graph.

  According to the present invention, it is possible to allow a user to recognize the cause of an increase in irradiation dose.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an irradiation dose abnormality analyzer 1 according to this embodiment.

  The irradiation dose abnormality analyzer 1 is used in, for example, a medical institution or an information service providing organization for a medical institution.

  The X-ray CT apparatus 2 has a function of transmitting inspection information related to the performed inspection to the network 3. The examination information includes information such as examination date, irradiation dose, examination site, patient age, patient weight, and various setting parameter values. The inspection information is received by the inspection information receiving device 4 via the network 3 and registered in the database 5. The irradiation dose abnormality analyzer 1 can acquire examination information from the database 5. Then, the irradiation dose abnormality analyzer 1 analyzes the abnormality of the X-ray irradiation dose in the inspection using the X-ray CT apparatus 2 based on the above inspection field method.

  The web server 6 and the mail server 7 are connected to the network 3. The web server 6 distributes web page data such as HTML (hypertext markup language) data via the network 3. The mail server 7 transmits e-mail data via the network 3. Irradiation dose abnormality analysis apparatus 1 enables browsing of analysis results using web server 6 or mail server 7.

  The irradiation dose abnormality analyzer 1 includes a processor 11, a main memory 12, a hard disk device 13, an input device 14, a display 15, and a network interface unit 16. These units are connected to each other via a bus 17.

  The processor 11 performs various control processes by executing software processes in accordance with programs stored in the hard disk device 13.

  The main memory 12 temporarily stores software extracted from the hard disk device 13 for the processor 11 to actually use. The main memory 12 is used as a work area for the processor 11.

  The hard disk device 13 stores an operating system program used by the processor 11. In addition, the hard disk device 13 stores various programs and other data. The data stored in the hard disk device 13 includes an irradiation dose abnormality analysis program 13a.

  The input device 14 receives various instruction inputs from the operator. As the input device 14, for example, a known device such as a keyboard, a mouse, and a touch panel can be used.

  The display 15 displays an image for presenting various information to the operator.

  The network 3 is connected to the network interface unit 16. The network interface unit 16 performs communication processing via the network 3.

  By the way, as this irradiation dose abnormality analyzer 1, a general purpose computer can be used, for example. In this case, the irradiation dose abnormality analysis program 13a is not initially installed. Therefore, as part of the introduction work of the irradiation dose abnormality analyzer 1, the irradiation dose abnormality analysis program 13a stored in a removable storage medium such as a CD-ROM is installed in the hard disk device 13. Alternatively, the irradiation dose abnormality analysis program 13a downloaded via the network 3 may be installed.

  By performing processing based on the irradiation dose abnormality analysis program 13a, the processor 11 realizes various functions as described below. One function compares and analyzes the relationship of a plurality of parameters related to the irradiation dose in one examination. One function identifies an abnormal cause of an examination in which the irradiation dose is abnormal based on the result of the comparative analysis. One function creates information for presenting the identified cause of abnormality. Another function creates information for presenting the result of the comparative analysis.

  Next, the operation of the irradiation dose abnormality analyzer 1 configured as described above will be described.

  FIG. 2 is a flowchart showing a processing procedure of the processor 11 based on the irradiation dose abnormality analysis program 13a.

In step Sa <b> 1, the processor 11 collects inspection information from the database 5. In step Sa2, the processor 11 extracts an abnormal test based on the collected test information. For this detection, for example, the following algorithm is used. This is used when creating a graph called Boxplot, and has a function to detect outliers. The extraction of the abnormal test is performed for each of a plurality of groups determined according to the age category to which the age of the patient to be tested belongs and the examination site.

(1) Data Alignment The irradiation doses shown in the collected examination information are arranged in ascending order.

Given the number of tests that have been extracted and N, the n-th irradiation dose to table as D (n).

  As a premise, the number of examinations extracted is N, and the nth irradiation dose is represented as D (n).

・ V75 (75% value)
Quarter1 ＝ (int) (N + 1) × 0.75
ADP (afte_the_decimal_point) = (N + 1) × 0.75−Quarter1
V75 ＝ D (Quarter1) + ADP × {D (Quarter1 + 1) -D (Quater1)}
・ V50 (50% value: mean)
If N is even
V50 = [D {(N + 1) / 2} + D {(N + 1) / 2 + 1}] / 2
If N is odd
V50 = D {(N + 1) / 2}
・ V25 (25% value)
Quarter3 = (int) (N + 1) 0.25
ADP (after_the_decimal_point) = (N + 1) × 0.25−Quarter3
V25 = D (Quarter3) + ADP × {D (Quarter3 + 1) −D (Quarter3)}
・ V0
V0 = V25−1.5 × (V75−V25)
(3) Calculation of threshold value The threshold value Thr1 is obtained from the following formula using the 75% value and the 25% value calculated above.

Thr1 = V75 + 1.5 × (V75−V25)
(4) Extraction of Abnormal Examination Of the irradiation doses respectively represented in the plurality of examination information collected in step Sa1, a dose larger than the threshold Thr1 calculated above is set as an outlier. The inspection information including the irradiation dose corresponding to the outlier is hereinafter referred to as abnormal inspection information. The inspection related to the abnormality inspection information is defined as an abnormality inspection.

  The processor 11 extracts an abnormal test in the same manner as described above even for each of a plurality of groups determined according to the weight category to which the weight of the patient to be tested belongs and the examination site.

  In step Sa <b> 3, the processor 11 creates a character string report that represents information related to the abnormality inspection as a character string. FIG. 3 is a diagram showing an example of a character string report. The character string report shown in FIG. 3 displays a list of various types of information included in the inspection information related to the abnormal inspection.

  In step Sa4, the processor 11 creates a graph indicating the presence of outliers. FIG. 4 is a diagram showing an example of the graph created here. The graph shown in FIG. 4 relates to one examination site. The outliers extracted as described above are plotted with the irradiation dose (CTDIw) on the vertical axis and the age division on the horizontal axis. In FIG. 4, for reference, V75, V50, V25, V0 and threshold value Thr1 are shown as shown in FIG.

  The processor 11 also creates a similar graph for the result of the abnormal test extraction process performed for each of a plurality of groups determined according to the weight category and the test site. In this case, however, the horizontal axis is the weight category.

  In step Sa5, the processor 11 determines a threshold value Thr2 relating to the irradiation time. This threshold value Thr2 can be determined by analyzing the irradiation time with the Boxplot algorithm. That is, after replacing D (n) with the n-th irradiation time, the above-described algorithm applied when extracting the abnormal inspection is applied.

  Thereby, for example, the threshold value Thr2 is determined as shown in FIG.

  In step Sa6, the processor 11 determines a threshold value Thr3 relating to the irradiation dose (irradiation intensity). For example, the following algorithm is used to determine the threshold Thr3.

(1) Least square method This time, the irradiation time is analyzed for the inspection information collected in step Sa1.

  A straight line indicating the overall trend is obtained using a least square method which is a kind of regression analysis. The straight line expression obtained here is determined as follows.

y = bx + a
In this equation, x is the irradiation time and y is CTDIw. a and b can be obtained by the following equation using the least square method.

b ＝ Σ (deviation of x) ・ (deviation of y) / Σ (deviation of x) ²
(deviation of x) = x-(average of x), (deviation of y) = y-(average of y)
a = (average of y)-b · (average of x)
The straight line obtained by such a method represents a tendency regarding the irradiation time and the irradiation dose as shown in FIG.
(2) Calculation of setting error threshold Perform Boxplot analysis again using the straight line obtained as described above and the distance to each plot. That is, the straight line obtained as described above is regarded as a horizontal axis, and the distance from the straight line to each plot is regarded as a value for each plot, and the above-described algorithm applied when extracting the abnormality test is used. Apply. Thereby, a straight line as shown by a broken line in FIG. 8 is obtained. A straight line indicated by a broken line in FIG. 8 is defined as a threshold value Tr3. The threshold value Tr3 determined in this way is a threshold value for eliminating an increase in irradiation dose due to an increase in irradiation time.

  In step Sa7, the processor 11 specifies the cause of the abnormality inspection. This is performed as follows by determining which of the four ranges delimited by the threshold values Thr2 and Thr3 belongs to the plot position of each examination in the graph representing the relationship between the irradiation time and CTDIw.

  (1) A plot position exceeding the threshold Thr2 line is specified as an examination in which the examination time is increased due to a lack of skill of the engineer and a longer examination time.

  (2) For a plot position that exceeds the threshold Thr3 straight line, it is specified that the irradiation dose is increased because the setting parameter at the time of imaging is not appropriate and the irradiation intensity is high.

  (3) For plot positions that exceed both the threshold Thr2 straight line and the threshold Thr3 straight line, specify that the examination is a combination of both insufficient skill and inappropriate setting parameters.

  In step Sa8, the processor 11 creates a graph representing the identified cause. FIG. 9 is a diagram showing an example of the graph created here. In the graph shown in FIG. 9, the relationship between the irradiation time and CTDIw for each inspection is indicated by a △ mark for the abnormal inspection identified as the cause of (1) above, and the abnormal inspection identified as the cause of (2) is ☆ Marks, abnormal tests identified as the cause of (3) are plotted by □ marks, and normal tests are plotted by ○ marks. In addition, a straight line with a threshold Thr2 and a straight line with a threshold Thr3 are shown.

  In step Sa9, the processor 11 creates a report report for reporting the analysis result. FIG. 10 is a diagram showing an example of a report report created here. In the report shown in FIG. 10, the character string report created in step Sa3 and the graph generated in step Sa8 are displayed side by side.

  In step Sa10, the processor 11 creates web page data and mail data. The web page data represents a web page for enabling browsing of the various reports created in the report report and the processing shown in FIG. The mail data directly represents the above report and various graphs, or represents an electronic mail representing a URL (uniform resource locater) for accessing the above web page data.

  In step Sa <b> 11, the processor 11 uploads the web page data and mail data created as described above to the web server 6 and the mail server 7. As a result, the web page can be viewed from a predetermined terminal via the network 3. The mail data is transmitted by the mail server 7 to a predetermined destination mail terminal, and the mail can be viewed on the mail terminal.

  As described above, according to the present embodiment, the cause of the increase in the irradiation dose in the abnormal inspection is specified for the abnormal inspection in which the irradiation dose is larger than those in other inspections. Therefore, the user can easily recognize the cause of the increased irradiation dose by confirming the identified result.

  Further, according to the present embodiment, for example, information for presenting a report as shown in FIG. 10 is created, so that the user's effort to confirm the result specified by the irradiation dose abnormality analyzer 1 is reduced. can do.

This embodiment can be variously modified as follows.
FIG. 4 and FIG. 4 show the result of comparative analysis of a plurality of examinations on the relationship between a plurality of parameters related to the radiation report and the irradiation dose without specifying the cause of the abnormal irradiation dose. A graph as shown in FIG. 7 may be presented. At this time, the corresponding character report or graph may be displayed alone, or may be presented as a report report as shown in FIG. 11, for example. At this time, it is effective to use at least two of the examination part, examination purpose, examination time, imaging time, CTDIw, DLP, slice width, imaging distance, tube current, and tube voltage as the parameters. . The combination of these parameters includes examination time and CTDIw, examination time and DLP, imaging time and CTDIw, imaging time and DLP, tube current and tube voltage, examination time and imaging time, imaging distance and CTDIw, imaging distance and DLP. The shooting distance and the slice width are effective.

  If such information is presented, the user can relatively easily determine the cause of the abnormality based on this information. Moreover, it represented to each graph like the straight line represented by the graph which showed the relationship between the irradiation time in FIG. 11, and CTDIw, and the curve represented by the graph which showed the relationship between tube current and tube voltage. By presenting the auxiliary line representing the tendency of the relationship on the graph, the user can more easily determine the cause of the abnormality.

  When one of plots represented in various graphs is selected, as shown in FIG. 12, it is possible to discriminate a plot of another graph related to the same inspection as that plot by changing the color, for example. , Improve convenience.

  When one of the plots represented in various graphs is selected, if information for specifying the examination related to the plot is presented as shown in FIG. 12, for example, convenience is improved.

  In addition to the method of least squares, a well-known analysis method such as an outlier detection method, principal component analysis, or cluster analysis that is used in BoxPlot can be applied to the determination of the line representing the relationship trend represented in the graph.

  The abnormality cause presentation method can be arbitrarily changed. For example, instead of changing the plot marks as shown in FIGS. 9 and 10, the colors may be different. In addition, for example, it may be possible to present a sentence such as “irradiation dose is excessive due to lack of skill in the inspection of ****”.

  The function of the inspection information receiving device 4 and the database 5 may be incorporated in the irradiation dose abnormality analyzing device 1.

  In order to analyze abnormalities in irradiation dose in other medical examination apparatuses that use X-rays such as an X-ray diagnostic apparatus that switches between fluoroscopic mode and imaging mode, and medical examination apparatuses that use radiation other than X-rays The present embodiment can also be applied.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

The block diagram which shows the structure of the irradiation dose abnormality analyzer 1 which concerns on one Embodiment of this invention. The flowchart which shows the process sequence of the processor 11 based on the irradiation dose abnormality analysis program 13a in FIG. The figure which shows an example of a character string report. The figure which shows an example of the graph which shows the presence condition of an outlier. The figure which shows how to represent V75, V50, V25, V0 and threshold value Thr1 in the graph shown in FIG. The figure which shows the example of determination of threshold value Thr2. The figure which shows an example of the straight line showing the tendency regarding irradiation time and irradiation dose. The figure which shows the example of determination of threshold value Thr3. The figure which shows an example of the graph showing the identified cause. The figure which shows an example of a report report. The figure which shows the modification of a report. The figure which shows the modification of an information presentation method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Irradiation dose abnormality analyzer, 2 ... X-ray CT apparatus, 3 ... Network, 4 ... Examination information receiving device, 5 ... Database, 6 ... Web server, 7 ... Mail server, 11 ... Processor, 12 ... Main memory, 13 ... Hard disk device, 13a ... Irradiation dose abnormality analysis program, 14 ... Input device, 15 ... Display, 16 ... Network interface unit.

Claims (8)

The radiation dose related to the examination performed by the medical examination apparatus that performs the examination by irradiating the subject with radiation and examination information including the first and second parameters different from the radiation dose are registered for each of the plurality of examinations. In the irradiation dose abnormality analyzer that can access the database ,
A plurality of inspections registered in the database as abnormal inspection information including inspection information including an irradiation dose larger than a threshold determined according to a distribution of irradiation doses included in each of the plurality of inspection information registered in the database Extraction means for extracting from the information;
For each of the abnormal inspection information extracted by the extraction means, the first and second graphs representing the relationship between the irradiation dose included in the abnormal inspection information and each of the first and second parameters are included. An irradiation dose abnormality analyzing apparatus comprising: a creating unit that creates presentation information. The creation means represents a relationship between an irradiation dose included in each of the plurality of inspection information registered in the database and a parameter different from the irradiation dose included in the same inspection information as the irradiation dose. The irradiation dose abnormality analysis apparatus according to claim 1, wherein a third graph is included in the presentation information. It said creation means, irradiation dose fault analysis according to claim 2, characterized in the inclusion of auxiliary lines representing the trend of variation of the irradiation dose definitive in the third graph in a state superimposed on the third graph apparatus. 2. The irradiation dose abnormality analysis apparatus according to claim 1, wherein the examination information includes CTDIw (computed tomography dose index 100) or DLP (dose length product) as the irradiation dose. The examination information, examination site, the inspection object, the inspection time, photographing time, slice width, Range, characterized in that it contains as said first and second parameters two of tube current and tube voltage The irradiation dose abnormality analyzer according to claim 1 . The radiation dose related to the examination performed by the medical examination apparatus that performs the examination by irradiating the subject with radiation and examination information including the first and second parameters different from the radiation dose are registered for each of the plurality of examinations. A computer that can access the database
A plurality of inspections registered in the database as abnormal inspection information including inspection information including an irradiation dose larger than a threshold determined according to a distribution of irradiation doses included in each of the plurality of inspection information registered in the database Extraction means for extracting from the information;
For each of the abnormal inspection information extracted by the extraction means, the first and second graphs representing the relationship between the irradiation dose included in the abnormal inspection information and each of the first and second parameters are included. An irradiation dose abnormality analysis program which functions as a creation means for creating presentation information. The creation means represents a relationship between an irradiation dose included in each of the plurality of inspection information registered in the database and a parameter different from the irradiation dose included in the same inspection information as the irradiation dose. The irradiation dose abnormality analysis program according to claim 6, wherein the program is made to function so as to include a third graph in the presentation information. It said creating means, according to the auxiliary line representing a trend of variation of the irradiation dose definitive in the third graph in claim 6, characterized in that to function to include in a state superimposed on the third graph Irradiation dose abnormality analysis program.

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