Scintillator selection for MR-compatible gamma detectors

We investigated the magnetic susceptibility of several scintillators to select the best material for MR-compatible gamma detectors. NaI(Tl) in an At container, NaI(Tl) in a Cu container and CsI(Tl) are candidates for MR-compatible gamma probes, imaging probes or SPECT, while BGO, LSO, LGSO, and GSO are the candidates for MR-compatible PET. In addition, we investigated image artifacts and distortion by scanning these scintillators with an MR-scanner. Results show that the magnetic susceptibility of NaI(TI), CsI(TI), BGO, and LSO showed similarities to that of human tissue. Of these scintillators, NaI(TI) in a Cu container showed the closest to that of susceptibility to human tissue and fewest artifacts on the MRI image. It is a good material for an MR-compatible gamma probe or imaging probe as well as SPECT. For MR-compatible PET, BGO, and LSO showed similar susceptibility to that of human tissue and small artifacts on the MRI images. However, LGSO and GSO showed much greater susceptibility than human tissue, and produced significant artifacts and distortion in the MRI images due to the presence of gadolinium (Gd) in these scintillators.