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Fig. 1 (abstract A24). | EJNMMI Physics

Fig. 1 (abstract A24).

From: Abstracts of the Total Body PET conference 2018

Fig. 1 (abstract A24).

Simulated count-rate performance for a 70-cm-long NEMA line source, containing either 18F or 124I and positioned 5 cm off-center within a 20.4-cm cylindrical attenuator, for 23-, 46-, and 70-cm axial field-of-view (AFOV) lengths corresponding to 1, 2, and 3 detector rings of the PennPET Explorer. Activity of each tracer was adjusted to yield equal rates of positron decays. (a) True + scatter (T+S) count rates (solid curves) and random (R) count rates (dashed curves) for 18F (black) and 124I (blue). T+S count rates for 124I were the same as those from 18F for equal positron-decay rates. 124I random rates (~7.1 x higher than for 18F) included double- and triple random events. (b) The count rates for 2 and 3 detector rings vs. a single ring increased appropriately with detection solid angle for this off-center source, when photon angles of incidence on the detector were restricted to be within ±45-degrees of normal incidence. (c) The resulting NECR for 124I and 18F for each system. The NECR for both 124I and 18F increased by factors of 3.9 and 8.3, respectively, for 2 and 3 detector rings, compared to a single-ring system

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