Scintillation camera

Claim 1

A scintillation camera apparatus including a camera head for detecting, in a matrix of points, radiation emitted from radioactive materials distributed in a subject and generating electric signals corresponding with said emitted radiation, said camera including a collimator, a scintillator, and a plurality of photomultipliers, position-calculating apparatus for calculating the radiation incidence position of an electric signal from said camera head, a pulse-height analyzer for generating an unblanking signal only when the emitted radiation exceeds background noise and display apparatus for reflecting the electric signals generated by the camera head, the improvement comprising: a memory having a plurality of addresses corresponding to the points of the matrix detected by said camera head; an address-designating apparatus supplied with the radiation incidence position from the position-calculating apparatus for issuing a signal designating the address in said memory corresponding to each radiation incidence position signal received and for driving the memory position to a successive position; control apparatus; means for transmitting said unblanking signal to said control apparatus; means triggered by the receipt of said unblanking signal by said control apparatus for comparing the content at the address designated by the address-designating apparatus with a predetermined minimum of acceptable radiation, said comparing means generating a first signal representing that said content of the memory at the designated address is less than said predetermined minimum value and a second signal representing that said content is at least equal to said predetermined minimum value; means for transmitting said first and second signals from said comparing means to said control apparatus, said control apparatus, (1) upon receipt of said first signal, adding one, representing said received designation signal, to said content and returning the increased content to the designated address, and, (2) upon the receipt of the second signal, issuing the unblanking signal to said display apparatus at the corresponding point of the display apparatus; and timing means for shutting off access of said unblanking signals to said display apparatus at a predetermined time, whereby said display apparatus reflects only radiation at least equal to said predetermined minimum at said predetermined time.