Prospects for time-of-flight PET using LSO scintillator
- Lawrence Berkeley National Lab., CA (United States)
The authors present measurements of the timing properties of lutetium orthosilicate (LSO) scintillator crystals coupled to a photomultiplier tube (PMT) and excited by 511 keV photons. These crystals have dimensions suitable for use in PET cameras (3 x 3 x 30 mm{sup 3}). Coincidence timing resolution of 475 ps fwhm is measured between detectors utilizing two such crystals, significantly worse than the 300 ps fwhm predicted based on first principles for small crystals and measured in 3 mm cubes. This degradation is found to be caused by the scintillation light undergoing multiple reflections at quasi-random angles within the scintillator crystal, which has two effects. First, it slows down the effective information propagation speed within the crystal (to an effective {cflx n} = 3.9--5.3). Since the incidence annihilation photon travels with n = 1, information from interactions at different depths arrives at the PMT with different time delays. Second, the random nature of the reflection angles (and path lengths) introduce dispersion and so a 10%--90% rise time of 1 ns to the optical signal.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Insts. of Health, Bethesda, MD (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 684494
- 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 IETNAE; ISSN 0018-9499
- Country of Publication:
- United States
- Language:
- English
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