Patent ID: 6291824
Filing Date: 2001-09-18
Classification: A61B,G01N

Abstract:
Apparatus for acquiring tomographic data from a sample, comprising a plurality of at least three emitters, a plurality of at least three detectors, and a timer, wherein:(a) each of said emitters is adapted to transmit pulses of collimated, near-infrared laser light to the sample;(b) each of said detectors is adapted to detect near-infrared light emerging from the sample in the vicinity of said detector, and to output raw tomographic data corresponding to the time and intensity of infrared light detected by said detector; wherein the gain of each of said detectors is variable, and wherein each of said detectors comprises a booster to temporarily boost the gain of each of said detectors at times corresponding to the arrival of weak near-infrared light pulses emerging, from the sample;(c) the positions of said emitters and of said detectors are stationary relative to one another, or said emitters and detectors are adapted to be fixed in positions that are stationary relative to one another;(d) said timer is adapted to control the relative timing of the pulses transmitted by said emitters, such that no detector simultaneously detects near-infrared light originating from more than one of said emitters; and such that the relative timing of subsequent pulses from different emitters is between about 5 nanoseconds and about 100 milliseconds; whereby infrared light detected by any one of said detectors at any particular time may be uniquely identified as having, originated from a particular one of said emitters.