Time-of-flight positron emission tomography using optical fiber circuit

The measurement method and system architecture of a new time-of-flight positron emission tomography (TOF-PET) system are proposed. This system collects scintillation light using optical fibers connected directly to scintillators and measures the position of positron annihilation. Many scintillators are placed cylindrically whereby a pair of scintillators detects a pair of gamma-rays generated at the positron annihilation point. Optical fiber circuits, most of which are bundles of optical fibers bound clockwise or counterclockwise around the cylinder of scintillators, collect light signals generated by gamma-rays. These light signals are amplified by several photomultiplier tubes and processed using a single digital oscilloscope to determine the TOF of the positron annihilation gamma-rays. One of the most important factors in the performance of the TOF-PET system is the TOF resolution. When fiber circuits are used for transmitting light signals, the dispersion of light signals and the decrease in light intensity are the major factors in the deterioration of the TOF resolution. The result of the preliminary experiment leads to the conclusion that the use of optical fibers degrades the intensity of light but does not severely degrade the TOF resolution.