GB1439986A - Medical diagnostic apparatus - Google Patents

Abstract

1439986 Photo-electric analysis of cells INST ELEKTRON I VYCHISLITEL TEKHNIK AKAD NAUK LATVIISK SSR 22 Aug 1973 39708/73 Heading G1A [Also in Division G4] Cytological preparations are analyzed by determining the area of each cell within each of a number of pre-selected density bands, each area being represented by a corresponding number of pulses, weighting the area according to the particular density band used by means of a pulse frequency divider, accumulating the weighted areas by means of a reversible counter the counting direction of which alternates between adjacent density bands, classifying the cell as normal or atypical according to whether the final value held in the counter is greater or less than a reference value, counting the total number of cells examined and the number of atypical cells detected, and classifying the preparation according to the proportion of atypical cells. As shown, Fig. 1, a scanning unit 4 comprises a TV camera viewing an area of the preparation through a microscope and operates under control of a unit 5. The scanning unit 4 incorporates a signal shaper and a level slicer capable of providing an output signal when the video signal lies in a band between selected pairs of sixteen density levels. Six of these bands are selected in turn by signals from the control unit 5. The output of the scanning unit is applied to an AND gate together with clockpulses so that the number of pulses produced is proportional to the area of a cell within the selected density band. This area is weighted according to the density level selected this being achieved by means of a variable divider unit 6 the division ratio of which is controlled by a counter (25) which is incremented by a pulse from from the control unit at each change of density band. The weighted output count is accumulated in a reversible counter 7, the counting direction being reversed at each change in density band, this producing in effect weighting coefficients of alternate signs. Before the measurement begins the reversible counter is set to a given value which corresponds to the subtraction of a constant from the total. The weighting factors are selected so that when all six density bands have been analyzed the counter holds a value which is positive for normal cells and negative for atypical cells. Two counters 26, 27 accumulate the number of atypical cells and the total numbers of cells examined respectively and when a total of 100 cells have been analyzed to output of counter 26 is decoded by logic circuit 3 to provide an output on line B, C or D depending on whether the preparation is normal, doubtful or pathological as represented by the number of atypical cells being below, between or above two threshold values. If the number of atypical cells exceeds the upper threshold value before 100 cells have been analyzed the preparation is classified as pathological and the measurement terminated.