Depth identification accuracy of a three layer phoswich PET detector module
- National Institutes of Health, Bethesda, MD (United States)
The authors describe a PET detector module that provides three levels of depth-of-interaction (DOI) information. The detector is a 9 x 9 array of 2 mm x 2 mm x 12 mm deep phoswich crystal elements, each consisting of 4 mm long LSO (entrance layer), GSO (middle layer) and BGO (exit layer) crystals joined optically together end-to-end. The BGO exit layer is directly coupled to a miniature position-sensitive photomultiplier tube (PSPMT). Delayed charge integration, a method that exploits differences in the light decay times of these scintillators, is used to determine the layer-of-interaction. DOI accuracy, measured by scanning a slit source of 511 keV radiation along the length of the module was 865 for the LSO layer, 805 for the GSO layer and 84% for the BGO layer. Energy resolution at 511 keV was 19% for LSO, 21% for GSO and 40% for BGO. Apparent gain differed between layers in the ratios 2.7:1.9:1.0 (LSO:GSO:BGO). Crystal separation was good between crystals in the LSO layer, acceptable between crystals in the GSO layer and poor between crystals in the BGO layer due, primarily, to the pronounced spatial non-linearity of the PSPMT. The delayed charge integration method, however, does appear suitable for obtaining multi-level depth information when DOI effects are particularly significant, e.g. in very small ring diameter PET scanners for small animal imaging.
- OSTI ID:
- 684496
- Report Number(s):
- CONF-981110--
- Journal Information:
- IEEE Transactions on Nuclear Science, Journal Name: IEEE Transactions on Nuclear Science Journal Issue: 3Pt2 Vol. 46; ISSN 0018-9499; ISSN IETNAE
- Country of Publication:
- United States
- Language:
- English
Similar Records
A room temperature LSO/PIN photodiode PET detector module that measures depth of interaction
Advantages using pulse shape discrimination to assign the depth of interaction information (DOI) from a multi layer phoswich detector