JPS6222437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear medicine data processing device that processes data collected by a scintillation camera.

Two types of conventional nuclear medicine data processing apparatuses are known, depending on their data collection methods: frame mode (image mode) collection and list mode collection. Of these, frame mode collection will be explained with reference to FIG. This converts the X and Y coordinate signals from the scintillation camera 1 into digital position coordinate signals by the A/D converter 2, and converts this into a digital position coordinate signal by the position calculation circuit 3 as an address selection signal for the storage device 4. The data at the address corresponding to the position coordinates in the storage device 4 is read out to the adding circuit 5, and after adding "1" to the read data by the adding circuit 5, the data is written to the read address again. There is. At this time, in order to calculate the address corresponding to the position coordinates in the storage device 4, as shown in FIG. (Y coordinate is J)
If so, the address A in the storage device 4 is given by the following formula (1)
It is determined by

A=J×N+I (1) Here, N indicates the length of one side of the matrix of the frame (image) to be formed. Assuming that N usually has a value that is a power of 2, this calculation involves arranging the X and Y coordinates in a line as shown in Figure 3.
This value can be used as address data. by the way,
The storage device 4 is generally a main storage device within a computer, but may also be provided separately inside a collection circuit.

The disadvantages of this frame mode collection are that if you try to increase the size N of the matrix that forms the image and improve the resolution of the image, you will need a larger storage capacity, and As a result of the addition circuit continuing to add "1" to the data, it exceeds the maximum capacity value at that address (hereinafter referred to as overflow), and it is not possible to express a larger value, and as a result, the data The problem arises that some parts are lost. For example, if the value of an address made up of 8 bits exceeds "255", an overflow will occur and data will be lost.

On the other hand, in list mode acquisition, as shown in FIG. 4, the X and Y coordinate signals from the scintillation camera 6 are converted into digital position coordinate signals by the A/D converter 7, and this position coordinate signal itself is stored. The data is written into the device 9. At this time, the write position is controlled by the output of the counter 8, and data is written in the order in which signals are generated starting from the first address of the storage device 9. At the same time, time data is sent from the timer 10 to the storage device 9 at predetermined intervals (for example, every 10 msec), and is written to the address selected by the counter 8 at that time. In this acquisition method, after a series of acquisitions is completed, position coordinate data and time data are processed using a computer to create and process an image similar to the image collected in the frame mode acquisition method. It is something.

One drawback of this wrist mode acquisition method is that a pair of X, Y from the scintillation camera
Since one address is required for each signal, a large capacity storage device may be required when the amount of data to be collected increases.

Therefore, when comparing frame mode collection and list mode collection, if the collection time is constant, frame mode collection requires less storage space when the amount of collection is large, but when an overflow occurs, the data will be lost.
Furthermore, when the amount of data to be collected is small, frame mode collection requires addresses even for portions where no data is actually collected, so list mode collection requires less storage capacity.

The present invention has been made in view of the above circumstances, and while having the advantages of the frame mode collection method, it is possible to prevent data loss due to overflow, and to reduce the capacity of the storage device in the collection circuit. The purpose is to provide a nuclear medicine data processing device that can perform

The present invention will be specifically explained below using Examples.

FIG. 5 is a block diagram showing one embodiment of the apparatus of the present invention. In the figure, 11 is a scintillation camera, 12 is an A/D converter that converts the X and Y coordinate signals from the scintillation camera 11 into a digital signal V _a , and 13 is an A/D converter 1.
A position calculation circuit outputs an address selection signal V _b which selects an address in the next stage storage device 14 based on a signal V _a from 2; arranged in a matrix. 15 is an addition circuit that adds "1" to the data read from the storage device 14, and 16 is a main storage device in the microcomputer, in which the write address is sequentially changed from the first address by the signal from the write position control counter 18. In addition to being selected, time data outputted from the timer 17 and changing at predetermined time intervals can be sequentially written into the selected address. Here, the adder circuit 15 takes in the data at a predetermined address in the storage device 14, adds "1" to it, and returns the data to the original address. It includes a discrimination circuit that outputs an overflow discrimination signal _Vc to the position calculation circuit 13 when the data exceeds the maximum storage capacity of the memory address (for example, the maximum value 255 expressed in 8 bits) (that is, overflow). I'm here. Additionally, the position calculation circuit 13 includes a switching circuit (for example, a multiplexer).
normally outputs the address selection signal V _b of the storage device 14, but when the overflow determination signal V _c from the adder circuit is input,
A switching operation is performed to output the input current position coordinate signal V _a to the main storage device 16 . Note that when an overflow occurs, the operation of the adder circuit 15 causes the memory device 1 to
"0" is written to the selected address No. 4. Furthermore, the counter 18 for selecting the address of the main memory device 16 is configured to count up every time the overflow determination signal V _c is output from the adder circuit 15 .

Next, the operation of the device will be explained. The X and Y coordinate signals from the scintillation camera 11 are converted into a digitized position coordinate signal V _a by the A/D converter 12 and input to the position calculation circuit 13 . The position calculation circuit 13 generates an address selection signal V _b to designate the address of the storage device 14 . The data at the selected address in the storage device 14 is taken into the adder circuit 15, and after "1" is added thereto, the data is returned to the original address. Here, if the addition result in the addition circuit 15 is "256",
The overflow discrimination circuit in the adder circuit 15 operates and outputs the overflow discrimination signal V _c , which causes the switching circuit in the position calculation circuit 13 to operate and input the current position coordinate signal V _a to the main storage device 16 . to be applied. Therefore, the position coordinate signal when the overflow occurs is input to the main storage device 16 and written to the address selected based on the operation of the write position control counter 18. On the other hand, "0" is written in the address in the storage device 14 where the overflow occurred. It is also possible to write time data from the timer 17 at fixed time intervals into the main memory 16 at an address selected based on the operation of the counter 18.

In this way, the image data is stored in the N×N×d (bit) storage device 14 and the main storage device 1
6 stores the coordinate data of the overflow point. Each of these data is processed in main memory 16 for display on a display device. That is,
For example, if the overflow point is X=X1 and Y=Y1, first all the contents of the storage device 14 are stored in another storage area of the main storage device 16, and then the data in the address area corresponding to the overflow point (X1, Y1) is stored. All you have to do is add the value of 2 ^d to . By supplying the image data obtained in this way to a display device, a scintillation image can be displayed on the display device.

According to the above-described embodiment device, although it has the advantage of the frame collection method in that the capacity of the storage device used in the data processing circuit can be reduced, it also has the advantage of reducing the capacity of the storage device used in the data processing circuit. It is also possible to provide a nuclear medicine data processing device that can prevent data loss.

The present invention is not limited to the embodiments described above, and various modifications can be adopted. For example, the storage device 1
The contents of 4 are 256 x 256 with all addresses being 1 bit.
The adder circuit 15 may also have a 1-bit configuration correspondingly. In this case, "1" is placed at the same address in the storage device 14.
If is added twice, an overflow will occur, and the position coordinate signal at that time will be stored in main memory 1.
It will be written within 6. Comparing this with the list mode acquisition method described above, the data written in the main memory 16 is different from the time series of the position coordinate signal actually input from the scintillation camera, and is slightly larger than the actual data. ,
Although it is thought that noise components are included, considering that the position signal from the scintillation camera is sufficiently "random," it is possible to obtain data that is almost the same as in the case of normal wrist mode collection. In this case, according to the device of the present invention, the capacity of the main memory device can be reduced to about half that of the conventional device.

Furthermore, by correspondingly changing the bit length of an address in the storage device 14 and the bit length at which overflow occurs in the adder circuit 15, it is possible to obtain an effect equivalent to the frame mode acquisition method when the bit length is large. Although it is possible to collect data without losing data due to overflow, and when the bit length is small, it can obtain almost the same effect as list mode collection.
In either case, the capacity of the storage device can be reduced.

It should be noted that the bit length at which overflow of the adder circuit 15 occurs does not have to be equal to the bit length of the storage device; for example, if overflow always occurs, it will be the same as in conventional list mode acquisition. Furthermore, it is clear that if the setting is made so that no overflow occurs, it will be equivalent to the case of conventional frame mode acquisition.

Also, the bit length of the storage device 14 is "8" and "1".
It goes without saying that this is not limited to the case of , and the same effect can be obtained even if it is changed arbitrarily.

According to the present invention described in detail above, nuclear medicine can prevent data loss due to overflow while taking advantage of the advantages of the frame mode acquisition method, and can reduce the storage device in the acquisition circuit. A data processing device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining a conventional frame mode collection method, FIG. 2 is a diagram showing the configuration of a storage device used therein, and FIG. 3 is a diagram showing the state of data written into the storage device. , FIG. 4 is a block diagram for explaining a conventional list mode collection system, and FIG. 5 is a block diagram showing an embodiment of the apparatus of the present invention. 11...Scintillation camera, 12...
A/D converter, 13...Position calculation circuit, 14
... Storage device, 15 ... Addition circuit, 16 ... Main memory device, 17 ... Timer, 18 ... Counter.

Claims (1)

[Claims] 1. In a data processing device that writes a scintillation image to a main storage device inside a computer based on coordinate signals from a scintillation camera, a data collection storage device provided outside the computer and a a position calculation circuit that selects a predetermined address in the data collection storage device based on the coordinate signal; and a position calculation circuit that reads data at the predetermined address in the data collection storage device selected by the position calculation circuit; An adder circuit that adds a predetermined value and writes it to the original location, and when the data at that address exceeds the maximum storage capacity, outputs an overflow determination signal and sets the data at the overflow point to 0; address selection means for sequentially updating the address designation of the main storage device each time upon receiving the overflow discrimination signal; and address selection means for sequentially updating the address designation of the main storage device each time; a nuclear medicine data processing device comprising means for storing data at an address of the main storage device designated by a selection means.