A Monte Carlo study of high energy prompt gamma-ray detection with LSO crystals

A novel imaging approach for small animals (mice) has been proposed and investigated primarily by Monte Carlo simulation. The new approach is called prompt gamma-ray imaging or PGI. This approach consists of irradiating small animals in the thermal neutron beam of a nuclear reactor to produce prompt gamma rays from the elements in the sample by the radiative capture (n, γ) reaction. These prompt gamma rays are emitted in energies and coincident chains that are characteristic of each element. Therefore, they can be used for imaging by using the principles derived from PET and SPECT imaging. In addition, the transmitted neutrons from the beam can be simultaneously used for very sensitive structure imaging, which provides the desired co-registration. For PET and SPECT imaging this must be obtained by a separate CT or MRI scanning device. In this new approach, the common gamma-ray energy range is from several kev to 11 Mev. The detection of high energy prompt gamma rays for this purpose is studied here by using currently available PET scanners; especially those that use LSO crystals. MCNP5is used to simulate these detection related issues.