PMC

Representative transverse slices from TOF reconstructed images for different setups. (A) F-18 after a 5-minute scan, (B) I-124 after a 5-minute scan and offset correction for true coincidence γ-ray background, (C) I-124 after a 20-minute scan and offset correction for true coincidence γ-ray background, (D) I-124 after a 5-minute scan and no special correction for true coincidence γ-ray background, and, (E) I-124 after a 20-minute scan and no special correction for true coincidence γ-ray background. In (D) and (E) the non-uniformity in the image is due to the presence of true coincidence events arising between one annihilation photon and the coincident 602 keV cascade γ, leading to an over subtraction of the estimated scatter at the center of the cylinder .

Illustration of Coincidence Events: (a) a single particle transiting the channel, (b) horizontal coincidence of two particles, (c) partial coincidence of two particles, (d) vertical coincidence of two particles.

Coincidence Correction: (a) Fitted model (red dashed) of first iteration of our proposed method overlaid on raw data (blue solid), (b) fitted model (red dashed) of second iteration overlaid on residual (blue solid) from first iteration, (c) fitted model (red dashed) of third iteration overlaid on residual (blue solid) from second iteration, (d) final residual (blue) from third iteration.

Timing histograms of coincidence timing between LSO-PSAPD detectors of . From top to bottom: No correction, FWHM 16.38 ± 0.05 ns; ASIC inter-channel delay correction, FWHM 8.42 ± 0.03 ns; inter-channel delay, signal amplitude and quadrature timing correction, FWHM 6.92 ± 0.02 ns; and the improvement of timing resolution with each calibration.