JPS6044634B2 - Scintillation camera device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention measures and stores errors due to nonlinearity of radiation detection positions in advance, and corrects the errors for each scintillation to be detected, making it possible to perform accurate diagnosis. The present invention relates to a scintillation camera device as described above.

Taking advantage of the fact that when a substance labeled with a radioisotope (hereinafter referred to as RI) is administered to a patient, the RI concentrates in a specific part of the patient depending on the nature of the substance. Diseases can be diagnosed by detecting gamma rays emitted from the RI from outside the patient's body and examining the distribution of the RI in the patient's body.

The device that measures this RI distribution is a scintillation camera. This device collimates gamma rays and converts them into light using a scintillator via a collimator that allows only gamma rays incident from a specific direction to pass. A device that detects the gamma rays using a plurality of photomultiplier tubes and outputs a position signal indicating the coordinate position corresponding to the incident position of the gamma ray from the detection output thereof; The system consists of a display device that measures the energy of incident gamma rays and displays a bright spot at the corresponding position when the energy falls within a predetermined range, and the bright spots that appear on the display surface of the display device are accumulated on a film, etc. By doing so, the distribution state of RI is measured.

A collection of bright spots showing the distribution of RI accumulated on the film is called a scintigram, and the shape, position, size, etc. of the lesion can be determined from the distribution of the bright spots. Figure 1 is a block diagram showing an example of a conventional anchor-type scintillation camera. In the figure, 1 indicates a wavelength at which a photomultiplier tube (hereinafter referred to as photomultiplier) 2 can measure incident gamma rays. scintillator (usually NaI (Tl)) for converting the photoelectrons into a plurality of photoelectrons.

When gamma rays enter the scintillator 1, they are converted into light at the point of incidence, resulting in a bright spot, but this light is arranged in a plane through a light guide 3 provided on the rear side of the scintillator 1 that guides the light. It is guided by a plurality of photomaru 2. Then, the scintillation light emitting position (bright spot light emitting position) of the scintillator 1 is determined based on the magnitude relationship of the output of each photomultiplier 2.
is calculated by the position calculation circuit 4, and the calculated
and output position signals XS and YS indicating the Y coordinate position,
It is applied to a display device 5 which will be described later. On the other hand, the pulse height analyzer 6 measures the energy of the gamma rays that caused scintillation in the scintillator 1 from the sum of the output signals of each photomul 2, and determines that this measured energy is within a predetermined range of the target gamma ray energy. When it is determined that An unblank signal U for bright spot display is given to a display device 5 using a cathode ray tube display.

Since the display device 5 is supplied with the position signals XS and YS, a bright spot is displayed at a position on the display surface of the display device 5 determined by the position signals XS and YS. In this way, tens of thousands to hundreds of thousands of counts of gamma rays emitted from the patient's body are detected, and during this time, the bright spots displayed on the display device 5 are accumulated on a film or the like to obtain a scintigram.
Diagnosis can be performed.

Incidentally, the position signal obtained by this type of scintillation camera generally has nonlinearity that differs depending on the detection characteristics and adjustment state of the radiation detector constituted by the scintillator 1, the photomultiplier 2, and the light guide 3.

Therefore, for example, even when uniform gamma rays are irradiated onto the detection surface of a radiation detector, the bright spot display image does not appear in a uniform distribution state, but instead appears as hot spots that are concentrated only at the position of each photomal. (that is, the bright spot density increases at each center of each photomul), or conversely, it may appear as a cold spot where the bright spot distribution density decreases at each photomul position. In order to correct the nonlinearity of the above properties, anchor-type scintillation cameras use a resistor matrix to extract the signal at an attenuation rate depending on the position of the photomal output. This nonlinearity is adjusted by giving nonlinearity to .

In addition, in anchor-type scintillation cameras using a delay line method, which uses a delay line to extract the output of a photomultiplier by giving a delay time depending on the position, the waveform is adjusted on the time axis when calculating the position. However, these adjustments are very delicate, and it is very difficult to completely eliminate the nonlinearity of the image. Furthermore, the nonlinearity in the position calculation of the scintillation camera is not only due to the above-mentioned causes, but also includes the collapse of the balance between photomuls due to changes over time, and various other changes over time.

Such nonlinearity causes problems in that diagnostic accuracy is reduced and maintenance of the device is difficult. Therefore, we measure the nonlinearity at regular intervals (for example, every morning), obtain the amount to be corrected for each spatial grid point from the results, and store this to determine the position of each radiation incident during actual imaging. By adding an appropriate correction signal to the signal and displaying a bright spot, nonlinearity can be corrected without compromising resolution or other image quality (for example, without converting the image into a digital image). device (patent application 1982-38)
No. 214) has already been developed, and Gerd Muehlener has disclosed in Japanese Patent Laid-Open No. 59886/1986 a method for correcting the nonlinearity of scintillation cameras, although only digital images can be obtained. .

However, in both of the above two inventions, at the stage of measuring the nonlinearity of the scintillation camera, for example, FIGS.
As shown in the diagram, a test model (hereinafter referred to as A phantom) is installed on the detection surface side of the radiation detector, and the image obtained by uniformly irradiating gamma rays onto the entire detection surface of the radiation detector is digitized and stored in memory. The position of each hole 22 or groove 23 of the phantom is determined from the accumulated information, the deviation from the actual position is determined, and the amount of correction to be corrected is calculated based on the deviation of each point using a scintillation camera device. A method is used in which the correction amount is calculated for each lattice point determined at regular intervals of the position signal in , and the above-mentioned correction amount is supplemented for each corresponding position.

However, in order to accurately determine the deviation from the actual position of each point from the above-mentioned digitized information, even if appropriate interpolation calculations are used, the effective field of view of the scintillation camera must be digitized sufficiently finely. I have to keep it.

For example, a minimum of 128X1 for an effective field of view of approximately 35 mm
2? It is necessary to digitize the degree. This means that a memory capacity of at least 16K words is required. On the other hand, the nonlinearity of scintillation cameras,
In other words, considering the spatial frequency of the deviation vector field between the actual position of each point and the average position obtained by averaging the statistical fluctuations of the position calculation results, when the spatial frequency of the array pitch of the photomuls is ``1'', the distance between the photomuls is The spatial frequency of nonlinearity due to the imbalance of
The frequency of cold spot) is 1 as the fundamental frequency,
The frequency components of 2 times, 3 times, etc. are overwhelmingly smaller than those of the fundamental frequency system.

Therefore, for a radiation detector in which 2-inch diameter photomuls are densely arranged in a hexagonal shape, it is approximately 5? It is sufficient to find the deviation of the grid points for each pitch and then use interpolation to find the deviation amount.Also, it is sufficient to memorize the correction amount at each grid point at a fixed interval of the position signal and calculate the deviation of the points in the grid. If the correction amount is determined by interpolation from the correction amounts of the four grid points surrounding the point, then the capacity of the memory for storing the correction amount in the device of the above-mentioned patent application No. 52-38214 (effective field of view/5 Gourd) 2
2, which is much smaller than the memory capacity required to obtain the vector field described above. In addition, using the hole-shaped phantom shown in Figure 2,
When trying to obtain a shift vector field by finding the position of the peak corresponding to each hole from the digitized information, the peaks with a large number of counts corresponding to each hole are discrete. It is relatively easy to find the peak position by interpolation, but if the radiation detector of the scintillation camera has large distortion globally, the peak position of each hole, that is, the peak position corresponding to each hole, is Establishing a correspondence between the case where the highest count is accumulated and the actual hole becomes a very complicated problem.

On the other hand, when the groove-shaped phantom shown in Figure 3 is used, the peaks are continuous in a ridge shape, so even if there is a large distortion, the correspondence between each peak and the actual position is as shown in Figure 2. Although this method is easier than using the fan l·, since each peak is not discrete, the algorithm for accurately determining the peak position becomes complicated.

As mentioned above, the conventional method requires a large amount of memory that is not used during actual correction at the stage of measuring the nonlinearity of the scintillation camera, and requires an algorithm to calculate the accurate amount of deviation. Even if it were to be carried out using software using a data processing device, it had the disadvantage of being very complicated.

The present invention has been made in view of the above circumstances, and the present invention calculates an output signal from a radiation detector that detects radiation using a position calculation circuit to obtain a position signal corresponding to the coordinates where the radiation has arrived. In this system, the arrival position of radiation is displayed as a bright spot each time radiation arrives in the desired energy range according to the target energy range.In order to measure nonlinearity in position calculation, collimated radiation is scanned on the detection surface of the radiation detector. A mechanism that allows the radiation to enter the radiation source while moving the radiation source, a circuit that calculates the average value of the position signal at that position each time the radiation source comes to a predetermined position, and stores this average value or the deviation from the actual position, and the amount of this deviation. A circuit that calculates the amount of correction at each lattice point of the position signal from the amount of deviation at each lattice point on the detection surface of the radiation detector, and stores it, and a circuit that stores it, and uses this stored content to actually calculate the amount of correction for the patient. By being equipped with a circuit that corrects the position signal by interpolation calculation each time radiation arrives within the target energy range during measurement, it is possible to accurately correct nonlinearity without using large capacity memory or complex algorithms. An object of the present invention is to provide a scintillation camera device that can perform the following.

An embodiment of the present invention will be described below with reference to FIGS. 4 to 9.

FIG. 4 is a wiring diagram showing the configuration of this device. In the figure, 1 is a scintillator that captures gamma rays and converts them into light, and 2 is a scintillator that connects the scintillator to the scintillator via a light guide 3 that is placed on the rear surface of this scintillator 1 and guides the light. It is a photomultiplier that detects light from 1 and generates an electrical signal corresponding to the detected amount of light.
A plurality of photomuls 2 are arranged in a plane so that light can be detected over almost the entire surface of the scintillator 1. 4 is the scintillator 1 from the output signal from each of these photomuls 2.
a position calculation circuit that calculates the light emission position of and outputs position signals XS and YS indicating the incident position (X, Y coordinate position) of the gamma ray; 5 is a display device using a cathode ray tube; 6 is the sum of the output signals from each of the photomultiples 2; a pulse height analyzer which outputs an unblank signal for displaying brightness when the value is within a predetermined level; The collimated point radiation source 7a is moved in a predetermined order at each predetermined position on the detection surface, and the spot radiation source 7a is placed at each predetermined position on the detection surface. This radiation source scanning device 7 is a radiation source scanning device that makes radiation incident in a horizontal direction.
It has a configuration similar to the drive mechanism of a Y plotter, and the point radiation source 7a (7) is slidably maintained in the X-axis direction (X1-X2) on a guide rail 7b extending in the X-axis direction. A configuration is used in which the guide rail 7b itself is moved in the Y-axis direction (Y1-Y2).

Reference numeral 8 denotes a drive/movement device for the radiation source scanning device 7, which is operated by the output of a controller to be described later to move the position of the point radiation source 7a.

9 receives the position signals XS, YS output from the position calculation circuit 4 when the wave height analyzer 6 determines that the energy of the incident gamma ray is within a predetermined range (that is, when outputting an unblank signal); , for example, a position signal averaging circuit that calculates the average value of the position signal of each of the X and Y coordinates for 1000 gamma ray detections, and 10 is a position signal averaging circuit that calculates the average value of the position signal of each of the X and Y coordinates for 1000 gamma ray detections.
A control output is given to the drive device 8 each time the point radiation source 7a is moved by a predetermined pitch in a predetermined direction.

11a and 11b are JA/D converters that convert the average value signal (analog value) of the position signal output from the position signal averaging circuit 9 into a digital signal; 12 is an A/D converter output from the position signal averaging circuit 9; A memory 13 stores the average value signal of the position signal for each determined position of the detection surface of the radiation detector, which is digitally converted and given by the D converters 11a and 11b, at an address corresponding to the position. memory 1
a calculation circuit that calculates, by interpolation, a correction amount at each grid point of the position signal set at a predetermined constant interval based on the memory contents of 2;
Reference numeral 14 denotes a memory for storing the obtained correction amount, and 15 reads out the correction amount stored in the memory 14 in opposition to the position signals XS and YS output from the position calculation circuit 4, and reads out the correction amount corresponding to the read correction amount. , the position signals XS, YS
This is a correction circuit that corrects the corrected position signal factor, {circle around (2)}, to the display device 5 together with the unblank signal US output from the pulse height analyzer 6.

Next, the operation of this apparatus having the above configuration will be explained. First, we will explain the process of measuring the nonlinearity of a scintillation camera. Suppose now that the point radiation source 7a is moved to one point to be measured and stopped. Gamma rays of a certain intensity are emitted from this point radiation source 7a and are incident on the corresponding position of the scintillator. As a result, the gamma ray incident point of the scintillator 7 emits light, and this light is incident on each photomultiplex 2 via the light guide 3. Since this incident light is attenuated according to the distance from the light emitting point, each photomultiplier 2 generates an output signal corresponding to the distance from the light emitting point. The output signals of each of these photomultipliers 2 are input to the position calculation circuit 4, where the position calculation is performed and
Position signals XS and YS corresponding to respective positions in the directions
occurs. On the other hand, the output signal from each photomultiplier 2 is input to a pulse height analyzer 6.

Then, the pulse height analyzer 6 provides a signal to the position signal averaging circuit 9 and the controller 10 each time it determines that the input is within a predetermined level and has the target gamma ray energy value. On the other hand, position signals XS and YS indicating the incident position coordinates of the gamma rays incident on the scintillator 7 are input from the position calculation circuit 4 to the position signal averaging circuit 9. At the time when the output is received, the position signals XS and YS are received, and these signals are integrated. This is performed for, for example, 100 times of incident gamma rays, and when 100 times are reached, the position signal averaging circuit 9 calculates the average value of the position signals XS and YS for 100 times of gamma rays. That is, the output from the pulse height analyzer 6 is counted by the controller 10.
000 times, this controller 10
A calculation command is given to the position signal averaging circuit 9 to execute the calculation. The specific resolution of the current scintillation camera detector is approximately 57 nIIL or less in terms of half-width, and its distribution exhibits an approximately Gaussian distribution. Since each light emitting position calculation process is probabilistically independent, 1000
By calculating the additive average of the position signals XS and YS of the light emitting point for each light emission, the reliability is 99.7% and about ±0.2? The average value of the position signal can be obtained with an accuracy of . If even more precision is required, or for a detector with poor resolution, the number of gamma ray incidences for calculating the arithmetic average may be increased to 2000 or 3000 times. The average value of the position signals XS and YS obtained in this way (or the deviation amount from the actual position) is digitized by A/D converters 11a and 11b for XS and YS, respectively, and the measured detection It is stored in the memory 12 as an average value of the position signal (or an average value of the amount of deviation) at the measurement point position of the device.

When the calculation of the position signal average value at a certain point is completed, the controller 10 outputs a position movement signal for one step to the drive device 8. This movement signal causes the drive device 8 to operate and move the point radiation source 7a of the radiation source scanning device 7 to a predetermined next measurement position. Then, as described above, the average value of the position signal for 1000 incidences of gamma rays at this measurement point is determined, and after digital conversion, it is stored in the memory 12 as the average value of the position signal at this measurement point position. In this way, the average value of the position signal at each predetermined measurement point is sequentially determined and stored in the memory 12.

As a result, each average value of the position signals XS and YS (or the average value of the amount of deviation) at each predetermined measurement point position on the detector has been obtained in the memory 12, so the calculation circuit 13 uses this stored content. The correction amount at each grid point of the position signal at each predetermined interval is calculated by interpolation, and the correction vector field is stored in the memory 14. By performing the above operations in a certain area, the measurement of the nonlinearity of the detector is completed and the correction operation is completed.

Next, the radiation source scanning device 7 is removed from the position facing the radiation detector, and the subject to whom RI has been administered is placed in its place (not shown, but at the same position as the radiation source scanning device).

). The subject to whom RI has been administered is targeted for diagnosis because of the property of the RI concentrating in the lesion.The gamma rays emitted from the subject cause the scintillator 1 of the radiation detector to emit light, and the light is emitted by the scintillator 1 of the radiation detector. Each of the signals is detected by the photomultiplier 2, converted into an electric signal, and inputted to the position calculation circuit 4 and the wave height analyzer 6. Then, the position calculation circuit 4 calculates the incident position of the gamma ray with respect to the scintillator 1, and the calculated position signals XS and YS are input to the correction circuit 15. Further, the pulse height analyzer 6 analyzes the level of the input signal from each photomultiplier 2, and when it determines that the level is the target gamma ray level, it provides an output signal to the correction circuit 15. As a result, the correction circuit 15 reads out from the memory 14 the correction amount of the position corresponding to the position indicated by the input position signals ), the necessary correction amount is obtained by performing interpolation calculation from the correction amount, and the position signals XS, YS are corrected by this correction amount. The corrected position signals XS and YS are given to the display device 5 as X and Y axis deflection signals. Further, in response to the output from the pulse height analyzer 6, the correction circuit 15 provides an unblank signal US to unblank the display device 5 at the end of position signal correction. As a result, the display device 5 displays the corrected position signal? A bright spot is displayed at the position determined by , ■. In this way, a point radiation source is placed at a predetermined position on the detection surface of a radiation detector, gamma rays emitted from this point radiation source are detected multiple times, and gamma rays detected at that fixed position are detected multiple times. The gamma ray position signals are averaged and stored, and this is performed at multiple locations on the detection surface of the radiation detector, and from the average value of each obtained position signal, the position signal grid points at predetermined intervals are calculated. The correction amount is determined and stored, and during actual measurement, the position signal output from the position calculation circuit 4 is corrected by the necessary correction amount obtained from the stored correction amount, and the display device corresponds to the corrected position signal. Since a bright spot is displayed at the position of the display screen, it is possible to accurately correct the nonlinearity of the radiation detector without using large memory or complicated algorithms, and it is possible to obtain highly accurate scintigrams. can get. In addition, since the position signal averaging circuit 9 adopts a method of sequentially integrating a certain position signal as an analog signal and averaging it, an A/D converter is installed in the latter stage to digitize it. A similar effect can be obtained by digitizing the signal and digitally averaging it to obtain the average value.

Next, a second embodiment of the present invention will be described.

First, using the radiation source scanning device 7 shown in FIG. 4, a measurer moves the collimated radiation source to each predetermined position on the detection surface of the radiation detector in a predetermined order. This is a method in which a signal indicating the movement is input every time the device moves, and the average value of the position signal (or the average value of the amount of deviation) at that point is calculated. Thirdly, as shown in FIG. 6, a phantom 61 as shown in FIG. 2 is fixedly attached to the front side of the scintillator 1, and the entire surface of the scintillator 1 is uniformly irradiated with gamma rays through this phantom 61. The transmitted gamma rays are converted into electrical signals, and the images are monitored using, for example, a memory scope 62 or the like.

At this time, the measurer can establish a correspondence between each hole of the phantom 61 and the image detected and displayed after passing through this hole, and set a region of interest of an appropriate size surrounding each image of each hole. A region of interest setting circuit 63 is provided before the memory scope 62.
will be established. At this time, the limbus of the region of interest is measured using a memory tape 6.
A bright line is displayed on 2 so that the measurer can monitor it along with the image of each hole. In addition, signals Xl, Yl, X2, Y2 and a positional signal
, YS is provided, so that only the position signals XS, YS within the region of interest are provided to the position signal averaging circuit 9. The measurer uses the region of interest setting circuit 6
3 to fit each hole of the phantom 61 into the region of interest one by one in a predetermined order.

For example, the image of the hole in the 1st row, 1st column → 1st row, 2nd column → 1st
It is in the third row and column. After locating the first row, first column, or the first hole, at the center of the region of interest,
When the switch 64a is pressed, a position signal corresponding to the position within the region of interest is extracted via the comparator 64 and input to the position signal averaging circuit 9. (Of course, at this time, the pulse height analyzer 6 separates the signals by energy.) Each time the switch 64a is pressed, the position signal averaging circuit 9 averages this signal for a fixed number of scintillations. Thereafter, the oil is converted into oil by A/D converters 11a and 11b as in the apparatus shown in FIG. 4, and is stored in the memory 12. The above operations are similarly performed for the second, third, . . . , nth holes, respectively, and stored in the memory 12. Thereafter, the calculation circuit 13 and memory 14 are used to calculate and store the correction amount, and the correction circuit 15 corrects the position signal by the correction amount read from the memory 4. If necessary, each read The necessary correction amount is obtained by performing interpolation calculation from the correction amount at the position signal lattice points (multiple lattice points), corrected, and applied to the display device 5 to correct non-linearity. In this case,
If it is difficult for the measurer to associate each hole of the phantom 61 with its image, it is possible to cover part of the hole of the phantom 61 with a heavy metal such as lead, so that the image of that part can be transferred to the memory scope 62. This makes it easier to make a correspondence.

The fourth option is to automatically move and install the region of interest, which requires the precondition that the degree of nonlinearity does not vary significantly globally. This is sufficient for fine nonlinear measurements (hot spots and cold spots for each photomultiplier described above) that are problematic in actual routine use.

That is, as shown in FIG. 7, the above-mentioned comparator 64 is provided at the downstream side of the position calculation circuit 4 and the pulse height analyzer 6, and a control circuit 7 for setting the region of interest and automatically shifting the region is provided.
1 and its output is given to the comparator 34.

That is, the above-mentioned position signals XS, YS are sent to the control circuit 7.
The comparator 64 together with the region of interest setting signal output from the
are input and compared, and it is determined whether or not it falls within the region of interest. If the pulse height analyzer 6 is present, the output of the pulse height analyzer 6 is given to the controller circuit 71 to be counted. Since the count rate is low while the region of interest does not include the hole image of the phantom 61, the control circuit 71 moves the region of interest in a predetermined order, for example in a rectangular shape as shown in FIG. 8, to search for the hole image. When the predetermined count rate is reached, the position signal that has entered the region of interest is accumulated in the position signal averaging circuit 9 via the comparator 64 until the predetermined count number is reached, and the position signal is accumulated for the predetermined count number. After obtaining the position signal, the average value is calculated and stored in the memory 12 mentioned above.
to be memorized. If the average value does not match the center position of the region of interest, move this value in the direction that matches the center position of the region of interest.
Move the region of interest and find the average value again. This operation is repeated several times for each hole image of the phantom 61,
The position signal average value signal at that time is determined. The following processing is the same as in the case of FIG. Fifth, all of the above-mentioned inventions are systems that obtain the non-linear deviation of the detector of the scintillation camera and then obtain the amount of correction. The radiation input position on the detection surface of the radiation detector that gives the set of position signals of the position for which the correction amount is to be determined is found as an average value, and that position is read. The correction amount at the lattice point is determined without calculation, and the nonlinearity is corrected by adding the correction amount.

That is, as shown in FIG. 9, the above-mentioned radiation scanning device 7 is arranged opposite to the detection surface side of the radiation detector.

When the wave height analyzer 6 determines that the energy is the target energy (when outputting an unblank signal), the position signal averaging circuit 9 averages the input position signal output from the position calculation circuit 4, This circuit also compares the correction amount at that time with the set of position signals Xj and Yj to be determined, and generates the difference as an output signal. 92 is a control circuit that processes the output signal from the position signal averaging circuit 9 according to methods based on adaptive control and learning machine theory (mathematically, a theory based on probabilistic approximation), and controls the radiation source scanning device. There is a circuit that controls the movement of 7.

Furthermore, the A/D converters 11a and 11b convert the output signal of the control circuit 92 into a digital signal, as in the embodiment described above, and store this digitally converted data in the memory 14. In such a device,
When the wave height analyzer 6 outputs an unblanking signal, the position signal averaging circuit 9 averages the position signals output from the position calculation circuit 4, and calculates the position signal Xi, Yj for which the correction amount is desired. A comparison is made with the set and the difference is output to the control circuit 92.

Upon receiving this output, the control circuit 92 controls the radiation source scanning device 7 (
By driving the drive device 8), the point radiation source 7a is moved to search for a position on the radiation detector that gives the position signal Xj, Y] as an average value. Control circuit 9
2 reads out the position X, Y of the point radiation source 7a from the drive device 8 when the position giving Xi, Yj is found with sufficient accuracy, and calculates the difference between this and Xi, Yi. Furthermore, these are digitized by A/D converters 11a and 11b, and Xi
, Yj is stored in the memory 14.
At the time of actual patient measurement, this correction amount is read out from the memory 14, and if more is required, the necessary correction amount is calculated from the correction amount at the plurality of position signal grid points for which the correction amount has been determined,
A correction is made to the position signal by this amount of correction. In this method, the control circuit 92 is required to have a judgment function when controlling the movement of the point radiation source, but there is no need for data processing at the stage of determining the correction amount. The I river 2 and calculation circuit 13 become unnecessary.

As detailed above, the deviation due to the nonlinearity of the radiation detector is determined for each point, and then the correction amount for each point 7 is determined and stored, and the position corresponding to the position signal is corrected during actual measurement. Since I read out the amount and added correction,
It is possible to provide a scintillation camera θ camera device having excellent features such as not requiring a large capacity memory and being able to easily and accurately calculate a correction amount.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional scintillation camera device, Figs. 2a and 3a are plan views showing a standard phantom for measuring nonlinearity of radiation detectors, and Fig. 2b 3b is a side sectional view thereof, FIG. 4 is a block diagram showing an example of the present invention, FIG. 5 is a plan view showing the configuration of the radiation source scanning device, FIGS. 6, 7, and 9. FIG. 8 is a diagram showing another embodiment, and FIG. 8 is a diagram showing an example of movement of the region of interest in FIG. 7. 1... scintillator, 3... light guide, 4... position calculation circuit, 5... display device, 6... wave height analyzer, 7... ...Point source scanning device, 7a... Radiation source, 8... Drive device, 9... Position signal averaging circuit, 10...
・Controller, 12, 14...Memory, 13
...Calculation circuit, 15...Correction circuit, 61
...Phantom, 63...Region of interest setting circuit,
64... Comparator.

Claims (1)

[Claims] 1. The energy of incident radiation is measured from the output signal of a radiation detector that detects incident radiation from a radiation source, performs radiation-electrical signal conversion, and generates an output signal, and determines whether this energy is at a predetermined level. In the apparatus which displays a bright spot on a display device when the radiation detector reaches a bright spot, the radiation source provided at a predetermined position on the radiation detection side of the radiation detector and the radiation detector A circuit that integrates position signals at the same measurement position every time radiation from a radiation source is detected and averages them for a predetermined number of times, and a circuit that stores the deviation between this averaged position signal and the measurement position. a circuit that calculates and stores a correction amount for a predetermined grid point of a position signal based on the stored content; and a circuit that reads out the correction amount corresponding to the position signal during actual measurement, adds correction, and provides the correction to the display device. A scintillation camera device characterized by being provided with a circuit. 2. The energy of the incident radiation is measured from the output signal of the radiation detector that detects the radiation incident from the radiation source and converts the radiation to an electrical signal to generate an output signal. When this energy reaches a predetermined level, the display device In the apparatus for displaying a bright spot on the radiation detector, a phantom is provided at a predetermined position on the radiation detection side of the radiation detector when nonlinearity correction data of the radiation detector is collected, and the phantom is formed with a hole for transmitting radiation at a predetermined position; A radiation source that uniformly irradiates the entire surface of the phantom with radiation, a circuit that sets a region of interest within the detection surface range of the radiation detector, a circuit that extracts a position signal included in the set region of interest; A circuit that averages the extracted position signals, a circuit that stores the deviation between this averaged position signal and the position of the region of interest, and a correction amount for a predetermined grid point of the position signal based on the stored contents. A scintillation camera device comprising: a circuit for calculating and storing; and a correction circuit for reading and correcting the amount of correction corresponding to the position signal during actual measurement and applying the correction to the display device.