SU604420A1 - Gamma-chamber - Google Patents

Description

one

The invention relates to experimental methods of nuclear physics and can be used to register X-rays of stars in astronomy and radioisotope diagnostic studies in medicine.

A gamma camera is known, whose collimators are using a narrow diaphragm H1 hole (pinhole) 1.

The disadvantage of such a gamma camera is the low efficiency (luminosity) of radiation detection.

A gamma camera with a multi-pinhole aperture plate is known, in which the holes are arranged randomly, occupying about 50% of the space of the plate 2.

The disadvantages of such a camera are nonlinear distortion and uniform illumination of the image (the presence of a pedestal) and the presence of a special device for analog decoding of experimental data.

 Closest to the proposed one is a gamma camera with a multi-pinhole aperture plate with a set of narrow-diaphragm holes, with half of the holes of which open during measurement.

set by the law of the mechanical system. The camera also contains a coordinate measuring transducer and a registrar p ..

The disadvantage of the camera is the complexity due to the presence of a mechanical system that changes the aperture of the camera over time, and a system for collecting, storing and processing the recorded information and controlling the mechanical system. As this system is used computer.

The purpose of the invention is to simplify the construction of a gamma camera at high

5 registration efficiency.

This is achieved by the fact that the gamma camera is equipped with a slit collimator, and the aperture plate consists of narrow diaphragm holes,

They are located in the form of straight parallel lines in accordance with the position of the units in any row of a non-degenerate circulatory matrix, consisting of ones and zeros, with the slit collimator partitions parallel to the lines of the narrow diaphragm holes and between them.

FIG. 1, 2, and 3 show the gamma camera, aperture plate, and slit collimator, respectively.

The gamma camera contains the object under study 1, the aperture plate 2, the jaw collimator 3, the coordinate measuring transducer 4 and the register 5. Figure 2 shows two variants of the aperture plate. In the example, an aperture plate is selected with the number of pinholes in each line -j-4, where N is the length of the pseudo-slideshow sequence of 1 and O, avn 7, and the number of lines M-7. FIG. 3 shows a slit collimator (the number of slits M-7).

The camera works as follows.

The object is placed under the aperture plate at a predetermined distance from it and one measurement is taken. After decoding the measurement results, the distribution of radionuclides on the selected plane in the object is obtained.

With the proposed technical solution, the slit collimator separates the images given by each row of pinholes, which allows separate decoding of the results obtained from each row of pinholes. Each of the M rows of pinholes, the number of which K is equal to the number 1 in the matrix row of order N, where N is also the number of image elements along one of the coordinates of the plane, gives K images of the object cut by each slit of the collimator. These images, besides the one given by the central Pinhole, are shifted to the right and left on the coordinate measuring transducer so much about the positions, how many pinholes, giving the image, are offset from the central pinhole. If the shifted image from each pinhole line is transferred cyclically to the image given by the central pinhole, then an image will be obtained, described by vector y, equal to Ax, where MF is the position vector of the sources in the object and A is a matrix of 1 and O order N.

By multiplying the inverse matrix A by vector 7, we obtain the desired vector G. A similar procedure is performed for all pinhole lines. When this matrix And can be the same (see Fig.2A) and different

(see FIG. 26) for each pinhole line.

The proposed gamma camera provides tight focusing depicts the PIA from the selected plane in the object. The distance between the pinholes (a), the magnification (or reduction) ratio of the image (p) and the distance between the aperture plate and the object (6) and the aperture plate and the plane under investigation (t) are equal to:

tl i a

   R w

d

where cf is the resolution of the gamma camera (the linear size of the source element).

A gamma camera has a luminosity K times greater than a single-pin camera. The proposed device in comparison with the known has a simple

about

design due to the lack of a system for storing and processing information and controlling the operation of the camera.

Claims (3)

1.Levkovich A.D. and others. Isotope biointroscopy. M., Atomizdat, 1973, p. 130. 2.R.H. Dicke, Csaffer Hole Cameras for x-rays an Gamma Rays Theme Astropysical Journal v. 153, 1968, pL 101. 3. US patent number 3840747, cl. 250-369, published. 1974. I I I .one