JPH0252278A - Scintillation camera - Google Patents

Abstract

PURPOSE:To economize a camera apparatus, to make it light in weight and to attain miniaturization by constituting an optimum position calculation circuit which forms the image of a gamma-ray with the aid of a signal from a detector. CONSTITUTION:A gamma-ray radiated from a material body 1 to be examined arrives at a scintillator 3 to emit light. The emitted light is detected and amplified by a photomultiplier 4, converted into voltage signals by a pre-amplifier 5 and inputted in a matrix adder 6 as the signals S1 to S4. In this place, individual matrix signals for the respective detectors D1 to D4 are added to them and inputted in the position calculation circuit 8. Then, the calculated values X and Y of the circuit 8 are inputted in a discriminator 9. Besides, the signals S1 to S4 inputted in a Z signal adder 7 receive the signals of total emitted light quantity by the gamma-ray and are inputted in a pulse-height analyzer 12. Moreover, signals U1 to U4 outputted from the analyzer 12 are inputted in the discriminator 9 and made to correspond to the calculated values X and Y of the circuit 8. The data of X, Y and U1 to X, Y and U4 is inputted in a correction circuit 10, corrected with a correction constant and fetched in a memory 11 which stores a positional coordinate so as to perform the calculation of a light emitting position with the aid of the detectors D1 to D4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a scintillation camera used for nuclear medicine image diagnosis, and more particularly to a scintillation camera configured with a plurality of detectors and aimed at high sensitivity.

[Conventional technology]

Scintillation cameras, known as nuclear medicine imaging diagnostic devices, are suitable for functional diagnosis of organs such as metabolism and blood flow in the human body, but have low sensitivity for detecting gamma ray information emitted from radiopharmaceuticals administered to the human body. This is a generally known fact. As prior art related to scintillation cameras, for example, US Pat. No. 3,011,
This is shown in Publication No. 057.

[Problem to be solved by the invention]

In order to improve the sensitivity of scintillation cameras, which are known as nuclear medicine image diagnostic devices, a two-detector type scintillation V-joon is used that uses multiple detectors to more effectively utilize gamma ray information emitted from the human body. There are cameras or multi-detector scintillation cameras. However, when increasing the detection sensitivity of the device by using a plurality of scintillation/camera detectors, sufficient consideration has not been given to the accompanying cost increase.

In conventional technology, a scintillation camera with multiple detectors has the same number of position calculation circuits as the number of detectors, but considering the amount of gamma ray information that must be stored, the position calculation circuit has sufficient processing capacity. However, there are still points that need to be improved from an economic standpoint.

The purpose of the present invention is to improve the sensitivity of the device by configuring an optimal position calculation circuit for creating a gamma ray image from the detector signals in a scintillation camera configured with multiple detectors. The goal is to provide all equipment.

[Means to solve the problem]

The above object is to provide a scintillation camera consisting of a plurality of nuclear detectors, which includes a detector in which a photomultiplier tube is optically coupled to a plate-shaped scintillator, and a position calculation means for determining the light emitting position of the scintillator. The calculation means includes a matrix adder that collectively collects light emission position information among the output signals of the plurality of detectors, a position calculation circuit that calculates the light emission position based on the output of the matrix adder, and a position calculation circuit that calculates the light emission position from the output signals of the plurality of detectors. This is achieved by a scintillation camera characterized by being equipped with a discriminator for identifying a detector corresponding to a calculation result, and by making the number of the position calculation circuits smaller than the number of detectors.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an embodiment in which the number of detectors is four and one position calculation circuit is provided. Gamma rays emitted from the subject 1 in all temporally discrete directions are detected by detectors Di, D2. D3. D4
Only gamma rays in a direction perpendicular to each of the collimators 2 attached to the scintillator 3 pass through, reach the scintillator 3, and emit light. Next, this light emission is detected and amplified by the photomultiplier tubes 4 arranged two-dimensionally in the scintillator 3, and further converted into a pressure signal by the preamplifier 5, and the signals 81 to S4
It is input to the matrix adder 6 as . The signals S1 to S4 input to the matrix adder 6 are used as data for calculating the light emission position. Here, each detector Di, D2. D
3. By superimposing and adding the individual matrix signals for D4 for the same matrix, a common total matrix signal Σxl, Σyr't for the four detectors D1 to D4 is obtained. Next, the total matrix signals ΣXl, ΣYj are input to a normal position calculation circuit 8, and the detectors DI, D2 . The comma ray detected by D3°U4 is sent to detector DI, D2°U3. After calculating the position of U4 all at once without distinction, the calculated values X and Y are input to the discriminator 9.

On the other hand, the detectors DI, D2. D3. The signal Sl of the photomultiplier tube 4 associated with each for D4.

S2. S3. S4 is input to the two-signal adder 7 and used as time data for non-tilator light emission.

The signals Sl, S2 . S3゜S4
is detector D1. D2. D3. Total luminescence amount (photoelectric absorption peak) signals SZI, SZ2.D4 due to gamma rays detected by D4.
SZ3,5Z4 (obtain r and use it as detector DI, D2.D
3. Each signal is input to the pulse height analyzer 12 corresponding to D4. Outputs Ul, U2 . of the wave height analyzer 12 . U3. U4 is the total light emission amount signal SZ1°SZ2. SZ3. It outputs only when the peak value of SZ4 corresponds to the total absorption of gamma rays, and at the same time the detectors Di, D2 . D3. D4 can be identified. Here, signals Ul, U2 . U3゜U4ff
By inputting i to the above discriminator 9, the calculation results of the position calculation circuit 8 are X, Y and Ul, U2゜U3. Make it correspond to U4. On top of that, X, Y.

Ul　,X,Y,U2　,X,Y,U3　,X,y.

The data of U4 is sent to detectors DI, D2. D3. D4 is input to the correction circuit 10 paired with each detector D1゜U2 . U3.
Correction constant C1 to correct the inherent spatial distortion etc. of U4
, C2, C3, and C4, and the data is imported into the memory 11 that stores the position coordinates. 1 by following the steps described above.
four detectors Di, U2 using four position calculation circuits 8;
．． The light emitting position is calculated using U3°U4. In this case, the final output signals X and Y are stored in the memory 1 as described above.
1 to detectors DI, D2. D3. Luminance modulation signals Ul, U2 . U3. It is output as a pair with U4.

In the above embodiment, the case where the number of detectors is four has been described, but the number of detectors is not limited to four and can also be applied to cases where a plurality of other detectors are used.

Further, the number of position calculation circuits is not limited to one as in the above embodiment, and the effect can be obtained as long as it is smaller than the number of detectors, so the present invention is applicable to those cases as well.

〔Effect of the invention〕

According to the present invention, in a scintillation camera configured with a plurality of detectors, at least one position calculation circuit is provided.
For example, in the case of a device consisting of four detectors, the position calculation circuit can be configured with one conventional one.
/4, which not only provides an economical effect, but also provides a significant effect in reducing weight and size.

[Brief explanation of the drawing]

FIG. 1 shows a block diagram of an embodiment of the present invention. 1... Subject, 2... Collimator, 3... Scintillator, 4... Photomultiplier tube, 5... Preamplifier,
6... Matrix adder, 7... 2-signal adder, 8...
Position calculation circuit, 9... Discriminator, 10... Correction circuit,
11... Memory, 12... Wave height analyzer.

Claims (1)

[Claims] 1. A scintillation camera comprising a plurality of detectors, including a detector in which a photomultiplier tube is optically coupled to a plate-shaped scintillator, and a position calculation means for determining the light emitting position of the scintillator. wherein the position calculation means is a matrix adder that collectively collects light emission position information among the output signals of the plurality of detectors;
A scintillation camera comprising: a position calculation circuit that calculates a light emission position based on the output of the matrix adder; and a discriminator that identifies a detector corresponding to the light emission position calculation result from the output signals of the plurality of detectors. 2. The scintillation camera according to claim 1, wherein the number of said position calculation circuits is smaller than the number of said detectors.