Minicamera for approximate detection of nuclear radiation emitted by a radioisotope and application to surgical assistance

摘要

The minicamera detects at least one beta and gamma nuclear radiation (or the like) emitted by a radioisotope contained in a body (1, 2). Its imaging head (300) comprises a collimator (301), a scintillator (302) and a photodetector assembly (303 to 309). According to the invention, the imaging head (300) is also provided with a modulation grid (312) having holes, which is arranged between the collimator (301) and the scintillator (302). Under the action of a suitable mechanism (313), the grid can open or close the collimator fully. The signals from the photodetector assembly which are collected in the opening position (or closing position, respectively) are supplied to a first (423) (second - 424, respectively) image memory. Comparison and calculation means (421) provide, by simple subtraction, the desired useful signal on the basis of the contents of the two memories (423, 424). Application: assistance for excision of cancerous tissue.