SU711716A1 - Apparatus for radioisotope diagnostics - Google Patents

Abstract

A DEVICE FOR RADIO ANALYSIS OF DIAGNOSTICS, containing a sensor connected via an amplitude discriminator to a pulse key, the control input of which is connected to the timer output for setting measurement intervals, and: the output is connected to the switch input, the outputs of which are respectively connected to the input of the background memory unit and the summing input the background subtraction unit, the subtractive input of which is connected to the output of the reading circuit, and the output of the background subtraction unit is connected to a accumulator connected to the indicator and the control input of the timer, characterized in that, in order to increase the accuracy and rapidity of measuring the percentage of radioactive substances in an organ, a disk * time recorder and a bit output digital information were inserted into the device, the time discretization input connected to the clock output of the timer, the time discretization output connected to control inputs cxeNEJ readout and a digital output circuit of digital information, the input of which is connected to the output of the background storage unit, and the output to the input of the readout circuit. (L

Description

The invention relates to i: medical technology, and can also be used in nuclear electronics in the implementation of radiometric and spectrometric instruments.

A device for radio-isotope diagnostics is known, which uses the method of comparing the intensity of radioactive radiation of a test organ with allowance for background radiation, in which the frequency of the background signals is set by a generator with a continuously varying frequency Ci.

The disadvantage of such a device is the complexity of the generator implementation with high accuracy of setting the absolute frequency value and frequency stability, varying over wide limits, as well as the need to manually set the frequency of the generator, which takes enough. Long time and reduces expressnet of the measurements.

The closest solution known is a device in which the background frequency of the background signals is determined by the background memory unit. The device for radioisotope diagnostics contains a sensor connected via an amplitude discriminator to a pulse key, the control input of which is connected to the timer output to set measurement intervals, and the output to the input of the switch, the outputs of which are respectively connected to the input of the background storage unit and the summing input of the block background subtraction, the subtractive input of which is connected to the output of the readout circuit, the output of the background subtraction unit is connected to a drive connected to the indicator and the control input of timer 2

The disadvantage of this device is the low accuracy of the measurements, due to the finite accuracy and the discrete nature of the background coming from the memory unit into the background subtraction unit in the measurement process.

 Insufficient background subtraction accuracy is due to the fact that in a known device a fixed number of background pulses are read from a background memory unit for a selected time interval, which inevitably leads to the necessity of rounding this output number with an accuracy of one least significant bit, and also that the last quantum of the output number is partially or completely lost, since the measurement ends at an arbitrary time and is not associated with the time of the next readout.

The aim of the invention is to improve the accuracy and expressiveness of

The percentage of the radioactive substance in the organ.

This is achieved by introducing a time sampler and a digital output digital information circuit into the device, the time sampler input is connected to the clock-giving output of the timer, the time sampler output is connected to the control input of the reading circuit and

0 are digital output circuits, the input of which is connected to the outputs of the background storage unit, and the output to the input of the reading circuit. The drawing is structural

g scheme of the proposed device for radioisotope diagnostics.

It contains a sensor 1 connected through an amplitude discriminator 2 to a pulse key 3, the control input of which is connected to the output

0 timer 4 for setting the measurement intervals, and the output to the input of the switch 5, the outputs of which are respectively connected to the input of the background storage unit 6 and the summing input of the background subtraction unit 7, the subtracting input of which is connected to the output of the readout circuit 8, the output of the background subtraction unit is connected to the accumulator 9 connected to the indicator 10. The input of the time sampler 11 is connected to the clock-giving output of the timer, and the time sampling output of the timer is connected to the control input of the readout circuit and the circuit .12

5 is a digital output, the input of which is connected to the background storage unit, and the output to the input of the readout circuit.

I The device works as follows.

0 way.

Gamma quanta of the background, detected by sensor 1 and exceeding the discrimination threshold in amplitude, are set by the amplitude discriminator

5 through a pulse key 3 and a switch 5, the accessions and accumulate in the background storage unit b for a certain time set by the control timer 4.

Q Then, a phantom is placed in the field of view of sensor 1; the timer is set to the accumulation time measurement mode, switch 5 to the upper position. When the pulse key 3 is connected to the background subtraction unit 7, the background pulses and impulses from the phantom arrive at the summing input of the background subtraction unit 7, at. In this case, the subtracting input of the subtraction unit receives impulses from cxevta 8

0 readings arriving at it from the background storage unit through the 12 bit digital information output circuit .:

Moreover, the time pulses from the timer 4 through the time discretization unit 11 are fed to the circuit 12 for serial output of digital information. The time digitizer 11 is a timer pulse frequency divider (for example, a decade scaler), the outputs of decades of which are connected to a digital output circuit 12 of digital information, while the outputs of decades of the digitizer receive pulses that control reading in a time multiple of ten . Circuit 12, of digitally outputted information, transmits information from the bits of the background storage unit, so that each selected time unit is read out information from the higher bit, each time the tenth pulse of the timer 4 is received, the time sampler 11 generates two pulses at the outputs of the decades, arriving at the inputs of the circuit 12 for digitally outputting digital information, which allows outputting information from the high bit of the background storing unit 6 and the next lower bit block. Thus, at ten By representing the numbers, the highest bit during the readout measurement is K times the next lower bit of K / I times, the next lower bits of K / 100 times, and t, e. At an average frequency of background pulses, for example, Pf 123,456 pulses / s the six bits in the counter will set the number 1123456 for 1000 s, then every hundredth: a fraction of a second you need to read the number 1, every tenth share - the number 2, every second - the number 3, etc. The number of bits read in this way can be set to depending on the required accuracy of the background subtraction. In the background subtraction unit, the background pulses of the sequence containing both the background and measured phantom pulses are subtracted, and the result is accumulated in the accumulator 9. When the specified number of pulses N is reached in the accumulator 9, the output of the accumulator 9 stops timer 4 (this is fixed the operating time and the signal from timer 4 lock the key 3. Setting the obtained measurement time produces an accumulation of pulses from the patient similar to measuring the radiation of a phantom, and this result will directly The relative content of radioactive substances in the organ, the use of the discretization time and diagrams of the bitwise output of digital information, combined as described above, favorably distinguishes the proposed radio-isotope diagnostic device from the known one, since the accuracy and rapidity of measurements is does not improve the accuracy of diagnosis of diseases of organs as a result of increased accuracy of background subtraction and reduce operating costs in the Kli ike, since the measuring accuracy is reduced a predetermined time of the survey.

Claims (1)

DEVICE FOR RADIO ISOTOPE DIAGNOSTICS, comprising a sensor connected via an amplitude discriminator to a pulse switch, the control input of which is connected to the timer output for setting measurement intervals, and the output to a switch input, the outputs of which are respectively connected to the input of the background memory unit and to the summing input a background subtraction unit, the subtracting input of which is connected to the output of the readout circuit, and the output of the background subtraction unit is connected to a drive connected to an indicator and a timer control input It is important that, in order to increase the accuracy and expressness of measuring the percentage of the content of a radioactive substance in an organ, a time sampler and a bitwise digital information output circuit are introduced into the device, and the input of the time sampler is connected to to the timer output, the output of the time sampler is connected to the control inputs of the reading circuit and the bitwise output circuit of digital information, the input of which is connected to the output of the background storage unit, and the output to the input of the reading circuit.