JP2013150695A - X-ray measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray measuring apparatus such as a bone density measuring apparatus capable of preventing an emergency such as a forced outage due to an increase in temperature of a heat source, or delaying the generation of the emergency.SOLUTION: A sensor for measuring the temperature of a heat source (in-unit temperature) is attached to an X-ray generator as a heat source, and a sensor for measuring a room temperature (out-unit temperature) is placed at a position distant from the sensor. A message 56 is presented to a user on the basis of a combination of two temperatures, and control details 58 are also applied. The message includes an instruction of reducing the room temperature and an instruction of prolonging measurement intervals. The control details include control for changing the number of cooling fans and control for changing the rotation speed of each of the fans. It is also preferable that if an forced outage occurs, a resumption time is predicted and the information of the time may be provided.

Description

  The present invention relates to an X-ray measurement apparatus, and more particularly to an X-ray measurement apparatus having a function of forcibly stopping X-ray generation by monitoring the temperature (heat source temperature) of an X-ray generation unit.

  As an X-ray measuring apparatus for measuring a subject using X-rays, a bone mineral content measuring apparatus, an X-ray imaging apparatus, a CT apparatus, and the like are known. Among them, the bone density measuring device will be represented and described. The bone density measuring apparatus includes a mounting table (lower part) that stores an X-ray generation unit, an upper part that is provided above the mounting table via a subject storage space, and stores an X-ray detector, an X-ray generation unit, and an X-ray detection unit An arm mechanism for connecting the device, a scanning mechanism for scanning the arm mechanism, and the like. Usually, the X-ray generation unit is provided with a temperature sensor composed of a thermistor or the like, thereby detecting the temperature (heat source temperature) of the X-ray generation unit, particularly the X-ray generation tube. The heat source temperature is monitored, and the operation of the X-ray generation unit is forcibly stopped when the heat source temperature reaches a predetermined upper limit temperature.

  Patent Document 1 discloses a radiation imaging apparatus having a sensor that measures the temperature inside the housing, a sensor that measures the temperature outside the housing, and a sensor that measures the humidity outside the housing. . A Peltier element as a temperature adjusting unit is controlled from detection results of these sensors. However, the temperature control is for preventing condensation while maintaining the X-ray detector at a low temperature. Patent Document 2 discloses an X-ray CT apparatus having a sensor for measuring the temperature in the gantry, but does not disclose detection of room temperature and control based thereon.

JP 2009-72361 A JP 2000-342568 A

  Although it is necessary to forcibly stop the X-ray generation unit when it overheats, conventionally, it has been carried out without notice, and there has been a problem that the measurement schedule is confused by a sudden forced stop. For example, in a bone densitometer, when a measurement is suddenly stopped during a sequence of measurements for a plurality of subjects, the subject who was the measurement target at that time is again Measurement will be forced, and the waiting state of the subject who is the measurement target will be prolonged.

  In the past, it was unclear as to when it was possible to return after a forced stop, that is, what information should be waited for several tens of minutes or several hours before the temperature dropped. It was not obtained, and a great burden was caused on both the examiner and the subject.

  An object of the present invention is to provide an X-ray measuring apparatus that can avoid the situation of forced stop of an X-ray generation unit as much as possible or can delay the occurrence of such a situation as much as possible.

  An X-ray measurement apparatus according to the present invention detects an X-ray generation unit that generates X-rays irradiated on a subject, a heat source temperature detector that detects the temperature of the X-ray generation unit as a heat source temperature, and detects a room temperature. A room temperature detector, and a control unit that executes a temperature rise suppression control that prevents the occurrence of a forced stop due to overheating of the X-ray generation unit or delays the generation time based on a combination of the heat source temperature and the room temperature. Including.

  According to the above configuration, the necessary control for suppressing the temperature rise can be executed in consideration of the room temperature as well as the heat source temperature, so that the control content can be made appropriate and appropriate for the situation. For example, in general, heat radiation from the heat source is weakened when the room temperature is high, and heat radiation from the heat source is strengthened when the room temperature is low. Therefore, the room temperature is an important factor in managing the temperature of the heat source. Other factors may be further considered. The heat source temperature detector can be installed inside or on the outer surface of the heat source (X-ray generation unit). It is also possible to detect the heat source temperature indirectly. It is desirable to provide the room temperature detector at a position on the apparatus where the heat from the heat source and conduction are not so much generated. It is also possible to install it outside the device. You may make it utilize the temperature sensor installed in the air conditioner. Each detector is composed of one or more sensors. When a plurality of sensors are used, for example, the maximum value, the average value, etc. are used as the temperature value. The temperature rise suppression control may include an increase in air cooling capability, current limitation, air conditioning temperature adjustment, and the like, and may further include provision of a message prompting the user to perform a predetermined action. According to the temperature rise suppression control, the occurrence of a forced stop of the X-ray generator unit due to heating can be delayed in time, or the occurrence of such a situation can be avoided in advance. It can be increased and the burden on the subject can be reduced. In particular, a forced stop during measurement can cause problems of re-measurement from the beginning, which should be avoided as much as possible. According to the said structure, possibility that such a problem will arise can be reduced.

  Preferably, the temperature rise suppression control includes providing a message to the user, and the content of the message is switched according to a combination of the heat source temperature and the room temperature. Preferably, the content of the message includes an instruction recommending that the set temperature of the air conditioning equipment be lowered, an instruction recommending a change to an operation mode that reduces heat generation, and a non-irradiation time ratio by increasing the measurement interval. At least one of the instructions to recommend increasing is included. If the user performs a predetermined action in accordance with such an instruction, the heat source temperature or the room temperature can be directly lowered, or the rise can be suppressed, so that the situation of reaching the upper limit of the heat source temperature can be avoided. Of course, it is also possible not to perform such a predetermined action at the discretion of the user. It is desirable to determine appropriately whether to automatically determine and control, or leave it to the user's determination and action according to the individual control contents.

  Desirably, the temperature rise suppression control includes a change in apparatus operating conditions, and the apparatus operating conditions are changed according to a combination of the heat source temperature and the room temperature. Preferably, the change in the apparatus operating condition includes at least one of a change in the number of cooling fan operations and a change in the cooling fan rotation speed. According to this configuration, the temperature rise is suppressed by adjusting the air cooling capacity. Or excessive air cooling can also be prevented.

  Preferably, when a forced stop of the X-ray generation unit occurs, a release time when the forced stop is released is predicted according to a combination of the heat source temperature and the room temperature, and time information indicating the prediction is provided to the user. Includes time information providing means. Preferably, the time information providing unit predicts the release timing at each time point and updates the time information according to a combination of the heat source temperature and room temperature detected at each time point at and after the occurrence of the forced stop. . According to this configuration, it is possible to predict the time until an operable state is reached from the combination of the heat source temperature and the room temperature. If it is provided to the user, it will be an indication of the resumption time. The prediction calculation may be performed by further referring to information other than the heat source temperature and room temperature at each time. Since the heat source temperature changes due to the forced stop and subsequent cooling measures, and the room temperature also changes due to temperature adjustment or the like, it is desirable to perform a prediction calculation in real time from the heat source temperature and the room temperature at each time.

  The prediction calculation of the release timing based on the combination of the heat source temperature and the room temperature can be used independently from the above temperature rise suppression control.

  Preferably, the X-ray measurement apparatus is a bone density measurement apparatus for measuring a bone density of a bone portion in a subject, and includes a lower part in which the X-ray generation unit is accommodated, and a subject accommodation space above the lower part. And an upper part that accommodates the X-ray detection unit, and the heat source temperature detector is disposed inside or outside the medium-filled container that accommodates the X-ray generation tube in the X-ray generation unit. And the room temperature detector is provided on the upper part. According to this configuration, since heat conduction from the heat source to the room temperature detector can be prevented, more accurate room temperature can be measured.

  According to the present invention, it is possible to avoid the situation of forced stop of the X-ray generation unit as much as possible, or to delay the occurrence of such a situation as much as possible.

It is a block diagram which shows suitable embodiment of the bone density measuring apparatus which concerns on this invention. It is a figure which shows the content of temperature rise suppression control. It is explanatory drawing which shows a temperature rise curve. It is a figure for demonstrating the calculation and display of resumption estimated time. It is a figure which shows an example of the table for calculating resumption estimated time.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of an X-ray measuring apparatus according to the present invention, and the X-ray measuring apparatus shown in FIG. 1 is a bone density measuring apparatus. The present invention can also be applied to other X-ray measuring apparatuses.

  In FIG. 1, a bone density measuring device is a device that measures the bone density (bone mineral content) of a bone part in a subject. Bone density measuring devices are installed in medical institutions such as hospitals. In particular, it is installed in a radiation control area. It generally constitutes a measurement chamber, and the measurement chamber is provided with air conditioning equipment for adjusting the room temperature. It is possible to adjust the room temperature by changing the set temperature of the air conditioning equipment.

  As shown in FIG. 1, the bone density measuring apparatus includes a measuring unit 10 and a controller 12. The controller 12 is constituted by a personal computer, for example.

  The measurement unit 10 will be described. The measurement unit 10 is roughly divided into a lower part 10A, an intermediate part 10B, and an upper part 10C. A bed 14 is provided in the lower part 10 </ b> A, and a subject (subject) 16 is placed on the bed 14. The measuring unit 10 as a whole extends in the direction of the central axis of the subject, and the subject 16 is placed on the bed 14 in a supine state, for example.

  An X-ray generation unit 18 is provided in the lower part 10A. The X-ray generation unit 18 has a case, and an X-ray generation tube 20 is provided in the case. The case is filled with insulating oil. In the present embodiment, a temperature sensor 21 that measures the heat source temperature (device internal temperature) is provided on the inner side surface of the case. Electric power is supplied from the high voltage source 22 to the X-ray generation tube 20. As the X-rays are generated, the X-ray generation tube 20 generates heat, so that the temperature of the X-ray generation unit 18 rises. When the upper limit of the temperature is reached, this is detected by the temperature sensor 21, and the operation of the X-ray generation unit 18, that is, the X-ray generation tube 20 is forcibly stopped by the temperature control unit 50 described later. This is the same control as the conventional bone density apparatus. However, in the present embodiment, the temperature control unit 50 performs the temperature rise suppression control so that such a forced stop situation does not occur or occurs after the situation becomes as late as possible. . The details will be described later.

  A filter unit 24 is provided above the X-ray generation unit 18. The filter unit 24 has a filter set 26 for alternately generating high energy X-rays and low energy X-rays, and the filter set 26 has a drum shape in the example shown in FIG. The filter set 26 is rotationally driven by a motor 30. High energy X-rays and low energy X-rays may be generated by controlling the applied voltage by the high voltage source 22. Reference numeral 23 denotes an X-ray beam. In this embodiment, a fan beam is generated.

  The lower portion 10A has a box-like shape extending in the horizontal direction, and several vent holes are formed on the side surface. The lower portion 10A is provided with a plurality of cooling fans 32, 34, 36, and 38 corresponding to the vent holes, and in the illustrated example, four fans are provided. Each fan is a suction fan or a blower fan. In any case, the air cooling can be performed on the inside of the lower portion 10 </ b> A, more specifically, the X-ray generation unit 18. Of course, a water cooling method may be applied.

  The upper part 10C is provided above the measurement space for accommodating the subject 16, and the X-ray detection unit 40 is provided in the upper part 10C. In the present embodiment, the X-ray detection unit 40 includes a plurality of X-ray sensors arranged one-dimensionally. These detection signals are output to a bone density image forming unit 44 described later.

  A temperature sensor 42 is provided in or outside the upper portion 10C. This temperature sensor 42 is a sensor for measuring the temperature outside the apparatus, that is, the room temperature. If the temperature sensor 42 is provided in the upper part 10C in this manner, it is possible to avoid the problem of heat wraparound from the X-ray generation unit 18 that is a heat source. Therefore, accurate room temperature can be measured.

  Reference numeral 46 denotes a transport mechanism. The transport mechanism 46 moves the measurement unit 18 and the detection unit 40 together in the body axis direction, that is, the direction perpendicular to the paper surface. As a result, the fan beam-shaped X-ray beam 23 moves linearly to form a two-dimensional data capturing area. Of course, a pencil beam may be formed in this embodiment. In that case, a two-dimensional zigzag scan is performed. As described above, high energy X-rays and low energy X-rays are alternately irradiated for each measurement position, and two detection data corresponding to them are acquired.

  Next, the controller 12 will be described. As shown in the figure, the controller 12 includes a bone density image forming unit 44, a control unit 48, a display unit 47, and the like. The controller 48 has a temperature control function as its main function, and is represented as a temperature controller 50.

  The bone density image forming unit 44 is a module that forms a bone density image (two-dimensional image) representing a bone part of the subject based on the detection data described above. The image data is sent to the display unit 47, and a bone density image is displayed on the display screen of the display unit 47. The control unit 48 has an image analysis function in addition to the function as the temperature control unit 50 described above, and calculates various types of information such as an average bone density within a region of interest set on the bone density image. The calculation result is also sent to the display unit 47.

  The temperature control unit 50 is a module that manages the temperature of the measurement unit 18, that is, the heat source, and executes control for suppressing the temperature rise. In order to perform such control, output signals from the temperature sensors 21 and 42 are given to the temperature control unit 50. The temperature control unit 50 executes control for suppressing temperature rise in the X-ray generation unit 18 as a heat source based on a combination of the apparatus internal temperature (heat source temperature) and the apparatus external temperature (room temperature). The contents of the control include message display on the display unit 47, change of operating conditions, and the like. This will be described in detail below with reference to FIG.

  Reference numeral 52 indicates an apparatus internal temperature, that is, a heat source temperature. In the example shown in the figure, it is divided into four sections, that is, a normal temperature, a warning level (low), a warning level (medium), and a warning level (high). The outside temperature 54 means room temperature, which is distinguished in this embodiment by two sections, high and low. Of course, three or more categories may be set. Based on the combination of the device internal temperature 52 and the device external temperature 54, a message 56 is provided to the inspector as the content of the temperature suppression control, and the control content 58 is applied as the device operating condition.

  For example, in the normal case indicated by reference numeral 60, no special control is executed. As indicated by reference numeral 62, if the warning level is low and the temperature outside the apparatus is high, an instruction to lower the room temperature and an instruction to set the measurement interval of the subject to 2 minutes or more are displayed as shown in the figure. The At the same time, control for operating one cooling fan and control for rotating the cooling fan at a low speed are executed. Next, as indicated by reference numeral 64, if the internal temperature 52 is a warning level (low) and the external temperature 54 is low, the message 56 only gives an instruction to set the measurement interval of the subject to 2 minutes or more. The control contents 58 are the same as those described above. That is, since the room temperature has already dropped to some extent, no instruction to lower the room temperature has been issued, and the temperature rise is suppressed by slightly increasing the degree of air cooling while increasing the measurement interval.

  As indicated by reference numeral 66, if the apparatus internal temperature 52 is a warning level (medium) and the apparatus outside temperature 54 is high, an instruction to lower the room temperature as a message 56, an instruction to increase the measurement interval, and high accuracy An instruction to refrain from the measurement in the mode and an instruction to refrain from the lateral measurement are issued, and control for operating two cooling fans and control for rotating these cooling fans at medium speed are executed as the control content 58. Since the measurement is performed at a slow speed in the high-accuracy mode, an instruction to refrain from such measurement is issued because the measurement time becomes long and the calorific value increases. Similarly, in the lateral measurement, the measurement is performed over a long and large range, and the measurement time increases. Therefore, an instruction to refrain from such a measurement is issued as described above. As indicated by reference numeral 68, if the apparatus internal temperature 52 is a warning level (medium) and the apparatus outside temperature 54 is low, an instruction to set the measurement interval as 5 minutes or more as a message, measurement in the high accuracy mode, Instructions to refrain from lateral measurements are given. In that case, it is recognized that the room temperature has already dropped to some extent, and no instruction to lower the room temperature has been issued. As the control content 58, the same as described above is applied.

  As indicated by reference numeral 70, if the device internal temperature 52 is at a warning level (high) and the device outside temperature is high, a message 56 indicates an instruction to lower the room temperature and a notification that the device cannot be operated until the device cools down. Is issued. That is, at that stage, the operation of the apparatus is forcibly stopped, and measures for increasing air cooling are applied. As the control contents 58, control for operating all four cooling fans, control for rotating the cooling fans at high speed, control for prohibiting X-ray irradiation, and control for stopping the rotation operation of the X-ray filter are executed. That is, a state where heat generation is not generated as much as possible and a state where air cooling is promoted is formed. At that time, a message indicating that the user cannot operate is provided to the user. As indicated by reference numeral 72, if the apparatus internal temperature 52 is a warning level (high) and the apparatus outside temperature 54 is low, a message 56 indicates that the apparatus cannot be operated until it cools down, and the control content 58 is the above. The same applies.

  As described above, by prompting a user to perform a predetermined action based on a combination of the internal temperature 52, that is, the heat source temperature, and the external temperature 54, that is, the room temperature, and appropriately changing the operating conditions of the apparatus The temperature rise of the heat source can be suppressed, the time to reach the upper temperature limit can be delayed, or such a situation can be prevented from occurring. Further, when cooling is not necessary, excessive cooling can be prevented, so that energy saving can be realized.

  FIG. 3 shows a temperature rise curve. The horizontal axis is the time axis, and the vertical axis indicates the temperature in the apparatus, that is, the heat source temperature. Reference numeral 80 indicates a case where no control is performed. In this case, the operation of the apparatus is forcibly stopped at the time when the heat source temperature gradually rises from the start of measurement and reaches the warning level (high) 74, that is, at the time indicated by reference numeral 86. On the other hand, in this embodiment, the warning level (low) 78 and the warning level (medium) 76 are set, and optimum control contents are applied to them when they reach the respective points. As shown in FIG. 5, it is possible to avoid reaching the warning level (high) in advance, or even if such a situation occurs, the time of occurrence can be delayed considerably.

  Next, the calculation display of the estimated restart time will be described based on FIG. 4 and FIG. If the time when the X-ray generation unit is cooled to a certain level and can be used is unknown to the inspector when the device is forcibly stopped, the inspection may be hindered or unnecessary for the subject. There is a problem of generating a heavy burden. Therefore, in the present embodiment, in the step indicated by reference numeral 88, a time during which the operation can be restarted, that is, a predicted restart time, is calculated based on the internal device temperature and the external device temperature. In that case, the table etc. which are demonstrated below are utilized. In the step indicated by reference numeral 90, the estimated restart time calculated in this way is displayed on the screen. An example of this is indicated by reference numeral 92, which includes information on the resumption time of X-ray irradiation, that is, information on how long to wait from the present time is provided. At the same time, information on the estimated restart time when the room temperature is lowered is also displayed.

  FIG. 5 shows a table that is referred to when calculating the estimated restart time. The horizontal axis 94 indicates the temperature outside the apparatus, and the vertical axis 96 indicates the temperature inside the apparatus. Each cell 98 represents time. For example, if the temperature inside the device is a specific temperature and the temperature outside the device is a specific temperature, the cell determined by them is referred to, and the estimated restart time is calculated based on the time information written therein. The There is a possibility that both the temperature inside the apparatus and the temperature outside the apparatus may change with time. In the above embodiment, the temperatures are referred to at each time, and the time determined by them is displayed. Therefore, the user can obtain an indication of how long to wait before starting measurement. In the example illustrated in FIG. 5, the combination of the device internal temperature and the device external temperature is referred to, but other information may be referred to.

  In any case, if the control for suppressing the temperature rise before the forced stop due to the temperature rise is applied, it is possible to prevent the situation such as the forced stop of the operation or to delay the timing of the occurrence of such a situation. . In addition, even if a forced stop occurs, measures for speeding up cooling can be applied, so that the forced stop period can be shortened, and in addition, time information that can be restarted in the meantime can be provided. Although the bone density measuring device is taken up in the above embodiment, which is convenient for the above, the present invention can be applied to other X-ray measuring devices.

  DESCRIPTION OF SYMBOLS 10 Measuring part, 12 Controller, 18 X-ray generation unit, 20 X-ray generation tube, 21 Temperature sensor, 24 Filter unit, 40 X-ray detection unit, 42 Temperature sensor, 50 Temperature control part.

Claims (8)

An X-ray generation unit for generating X-rays irradiated on the subject;
A heat source temperature detector for detecting the temperature of the X-ray generation unit as a heat source temperature;
A room temperature detector for detecting the room temperature;
Based on the combination of the heat source temperature and the room temperature, a controller that performs temperature rise suppression control that prevents the occurrence of a forced stop due to overheating of the X-ray generation unit or delays the generation time thereof;
An X-ray measuring apparatus comprising: The apparatus of claim 1.
The temperature rise suppression control includes providing a message to the user,
The X-ray measuring apparatus, wherein the content of the message is switched according to a combination of the heat source temperature and the room temperature. The apparatus of claim 2.
The content of the message includes an instruction to reduce the set temperature of the air conditioning equipment, an instruction to recommend switching to an operation mode that reduces heat generation, and increase the non-irradiation time ratio by increasing the measurement interval. Including at least one of the recommended instructions,
An X-ray measuring apparatus characterized by that. The device according to any one of claims 1 to 3,
The temperature rise suppression control includes a change in device operating conditions,
The apparatus operating conditions are changed according to the combination of the heat source temperature and the room temperature.
An X-ray measuring apparatus characterized by that. The apparatus of claim 4.
The change in the apparatus operating condition includes at least one of a change in the number of cooling fan operations and a change in the cooling fan rotation speed.
An X-ray measuring apparatus characterized by that. The device according to any one of claims 1 to 5,
Providing time information to the user for predicting the release time when the forced stop is canceled according to the combination of the heat source temperature and the room temperature when the X-ray generation unit is forced to stop Including means,
An X-ray measuring apparatus characterized by that. The apparatus of claim 6.
The time information providing means updates the time information by predicting the release time at each time point according to the combination of the heat source temperature and room temperature detected at each time point when the forced stop occurs and thereafter,
An X-ray measuring apparatus characterized by that. The apparatus of claim 1.
The X-ray measurement apparatus is a bone density measurement apparatus that measures the bone density of a bone portion in a subject, and includes a lower portion in which the X-ray generation unit is accommodated and a subject accommodation space above the lower portion. An upper part provided with an X-ray detection unit,
The heat source temperature detector is provided in the X-ray generation unit inside or outside a medium-filled container containing an X-ray generation tube,
The room temperature detector is provided on the upper part,
An X-ray measuring apparatus characterized by that.

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