| 摘要 |
PCT No. PCT/GB94/02301 Sec. 371 Date Mar. 22, 1996 Sec. 102(e) Date Mar. 22, 1996 PCT Filed Oct. 20, 1994 PCT Pub. No. WO95/11461 PCT Pub. Date Apr. 27, 1995A method of detecting the presence and position of radio isotope material in a sample is described comprising the steps of: exposing the sample to a phosphor, repetitively imaging the phosphor onto an image intensified CCD camera, scanning the camera CCD array and interrogating the charge pattern thereon following each exposure, performing measurements on the data signals obtained thereby to identify clusters of data values from adjacent regions of the array caused by light emitted by the image intensifier onto those regions and comparing the measurements with threshold values and parameter values so as to distinguish clusters resulting from light emitted as a result of radioactive decay events energizing the phosphor, from other light producing events, computing the centroid of each cluster of data values identified as a radioactive decay event with reference to the camera array and storing the centroid coordinates in a memory together with the centroid coordinates of any other radioactive decay produced clusters identified during the same interrogation. Coordinates from each of a succession of interrogations of the same sample are stored in an accumulation store, which can be read out to give a list of recorded events and/or used to produce a display of the events superimposed on an outline of the sample. The samples are carried on fibre optic plates in contact with the photocathode and event coordinates are stored in memory as they are detected, so that the display is updated as the events occur. Low noise bi-alkali material is used for the photocathode and the CCD camera is operated in inverted mode to reduce noise.
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