Speaker
Description
Background and aims:
Digital PET systems based on silicon photomultipliers (SiPM) provide improved spatial and timing performance compared with analog photomultiplier tube (PMT) detectors. This study compares a digital GE Discovery MI (20 cm axial FOV, 4 rings) with an analog GE Discovery IQ (26 cm axial FOV, 5 rings) through standardized quality control tests [1].
Methods and materials:
Both systems were evaluated using the standardized quality control tests PET02 (spatial resolution), PET03 (sensitivity), PET04 (NECR peak), PET06 (image quality), and PET08 (timing). Analogous phantoms and acquisition parameters were used.
Results:
Spatial resolution was superior in the digital PET due to its smaller SiPM detector elements, with both systems converging only at large radial distances. Sensitivity was higher in the analog PET, mainly due to its larger axial FOV and higher number of detector rings. At higher activity concentrations, both systems showed similar true count rates near 5 kBq/mL. The digital PET exhibited a substantially higher NECR peak at higher activity levels and maintained performance across a wider concentration range, despite having slightly higher scatter fractions. Image quality demonstrated greater contrast recovery in the digital PET, although local uniformity around high contrast regions was slightly reduced, likely due to its shorter axial FOV requiring more bed positions. The smaller number of detector rings also increases total acquisition time. However, timing resolution strongly favored the digital system, enabling effective TOF correction.
Key words:
Digital PET; Analog PET; NECR; Sensitivity; SiPM; Timing; Image quality.
[1] SEFM, Protocolo de Control de Calidad de la Instrumentación en Medicina Nuclear. 2020.
| Track | FTMI |
|---|---|
| Presentation type | Poster |