Patent ID: 8859973

Claim:
A strip device for determining a location and a time of a gamma quantum reaction, comprising a scintillation chamber, wherein said scintillation chamber has an internal cylindrical surface at which there are arranged a plurality of scintillator strips, wherein surfaces of said scintillator strips are configured to reflect photons falling on said surfaces from inside of said scintillation chamber at an angle greater than a boundary angle, each scintillator strip being optically connected to photomultipliers for receiving, via light-guides, photons of light, resulting from a gamma quantum absorbed in a scintillator material of said scintillator strip, wherein an energy of said gamma quantum is transferred entirely to an electron of said scintillator material via a photoelectric effect or partially via a Compton effect, which reach a front edge or a rear edge of said scintillator strip, and wherein said device further comprises an electronic system for determining a location of annihilation points along lines of response, said electronic system being configured to: (a) select events for which signals are registered within a fixed time interval in a pair of said scintillator strips spaced with a relative distance, and (b) for each selected event, i) determine a point of impact of said gamma quantum in a plane perpendicular to a longitudinal axis of said scintillator strip from a position of said scintillator strip that registered said signal, and ii) for each scintillator strip of said pair of scintillator strips which registered said signal for said selected event: (1) determine an impact position in said scintillator strip along said scintillation chamber on a basis of a time difference (t_front-t_back) between a front time (t_front) measured in a front photomultiplier and a back time (t_back) measured in a rear photomultiplier of said scintillator strip, (2) determine an interaction time (t 1 , t 2 ) when said gamma quantum interacted in each scintillator strip as an arithmetic mean of said front time (t_front) measured in said front photomultiplier and said back time (t_back) measured in said rear photomultiplier of each scintillator strip, (3) determine an energy of an electron of said scintillator material to which the energy of said gamma quantum was transferred by means of the Compton effect or the photoelectric effect, on a basis of amplitudes of said signals measured in said photomultipliers on both sides of said scintillator strips, iii) determine a line of response on a basis of said determined impact positions in said two scintillator strips of said pair of scintillator strips, iv) determine a place of annihilation along said line of response based on said determined interaction times (t 1 , t 2 ), (c) provide a tomographic image from a set of said determined lines of response and said places of annihilation along said lines of response determined for each of said selected events, and (d) wherein said scintillator strips are made of plastic doped with atoms with atomic number of at least 50.