General Lab Information

Technologies Available for License

2015-020: Time-of-flight PET (TOF-PET) detectors

Invention: 2015-020

Patent Status: U.S. Patent Number 10,132,942 was issued on November 20, 2018

For technical and licensing related questions, email


The large radiation dose inherent in current PET diagnostics renders PET unsuitable for certain patient populations, as well as clinical settings. For example, the use of PET for children is recommended only for extreme cases, and that PET cameras are found largely in urban hospitals. This significantly limits the prescription of PET as a diagnostic compared to other diagnostic tools, such as X-rays. In this joint invention, researchers from Brookhaven and U of Chicago described TOF-PET detectors by combining low density scintillator materials, such as liquid scintillator materials, with photodetectors having very high temporal resolution (1 mm or better) to provide enhanced sample imaging. The TOF-PET detector systems use large-area photodetectors with extremely high time-resolution (picoseconds) and an approach to data collection and analysis that allows for the use of inexpensive low-density scintillator materials.


The imaging of a sample using the TOF-PET detector systems is carried out by placing a sample that emits coincident gamma ray pairs between a pair of the TOF-PET camera modules. The first and second gamma rays of the pair arrive at the first and second TOF-PET camera modules, respectively, within a given coincidence detection window (e.g., within 50 psec of one another). Both gamma rays travel at the velocity of light in vacuum in the scintillator material. The first and second gamma rays, which behave as particles in the low density scintillator material, interact with that material in the first and second TOF-PET cameras, respectively, to produce a plurality of optical photon-emitting Compton Scattering energy deposition events and photoelectric energy deposition events in those materials. The wavelengths of the optical photons are long relative to the spacing of the atoms in the scintillator material and, therefore, the photons act as waves in the material, travelling at less than the speed of light in vacuum. The position of the source of each gamma ray pair is determined by identifying, on a statistical basis, the first (earliest) optical photon-emitting energy deposition event(s) in the scintillator materials of opposing TOF-PET camera modules. The positions, including depths of interaction, of the identified first energy deposition events within each of the scintillator materials can be used to calculate a statistically probable (e.g., 1σ and 2σ) volume for the site of the positron/electron annihilation in the sample (the gamma source position) based on a straight line connecting the identified first energy deposition events and intersecting the sample (a line of response; LOR). An image of the gamma photon-emitting region in the sample is then generated based on the calculated gamma source positions.


The use of large-area photodetectors in the TOF-PET detector systems allows for an increased geometric acceptance for coincident gamma rays, relative to conventional TOF-PET detector systems, and makes it possible to image a human upper body in a single exposure without moving the photodetectors. As a result, the use of the detector systems in patient imaging is advantageous because it allows for the use of smaller doses of radiation and/or shorter exposure times.

Applications and Industries

The applications of TOF-PET detector systems described here range from medical imaging to studying fundamental physics such as nucleon decay and neutrino physics to physics with broader application such as neutron detection.

Journal Publication & Intellectual Property