Parallel hole collimators are ~25–80 mm thick and contain 3–9 × 104 holes. Originally the holes were circular but are now usually hexagonal, in low and medium energy collimators, and constructed by assembling strips of lead foil. High energy collimators still have round holes, although square or triangular holes are sometimes used in high sensitivity collimators. These tend to be constructed using a casting technique (IPSM 1992). The latter has been improved recently and, since the uniformity of cast collimators is generally better than that of foil, these are now recommended in low and medium energy collimators, especially for SPET (Moore et al. 1992).
KeywordsAttenuation Hexagonal Tungsten Lution Reso
full width at half maximum
line spread function
point spread function
single photon emission tomography
ultra high energy
very high energy
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- IPSM (1992) Report 66 quality control of gamma cameras and associated computer systems. Institute of Physical Sciences in Medicine. LondonGoogle Scholar
- Sorenson JA, Phelps ME (1987) Physics in nuclear medicine, 2nd edn. Grune and Stratton, New YorkGoogle Scholar
- Tsui BMW, Gunter DL, Beck RN, Patton J (1996) Physics of collimator design. In: Sandler MP, Patton JA, Coleman RE, Gottschalk A, Wackers FJT, Hoffer PB (eds) Diagnostic nuclear medicine, 3rd edn. Williams and Wilkins, Baltimore, pp 67–79Google Scholar