A low-dose protocol in pediatric ¹⁸F-FDG scans using 30-cm axis field of view PET/CT

To explore the feasibility of a low-dose ¹⁸F-FDG protocol for the 30-cm standard axial field of view (SAFOV) PET/CT imaging in pediatric patients.

A retrospective analysis was conducted on 112 pediatric patients who underwent a full-dose (3.7 MBq/kg) ¹⁸F-FDG PET/CT imaging, and a prospective analysis was performed on 55 patients who received a low-dose (2.5 MBq/kg) imaging. PET images were reconstructed at 1.0-min/bed intervals, and labeled as G1.0, G2.0, G3.0 for the full-dose imaging and G1.0', G2.0', G3.0' for the low-dose imaging. Patients were categorized into three age groups, and the image quality was assessed using the Likert scale and signal-to-noise ratio (SNR); Lesion detectability was evaluated using lesion detection rates and the target-to-liver ratio (TLR).

In G2.0 and G3.0, all cases (112/112) achieved an image score of ≥ 3 and a lesion detection rate of 100% (98/98). There were no significant differences in SNR between G2.0 and G3.0 (11.09 ± 2.31 vs. 11.88 ± 2.58, p = 0.39), nor between age groups ≤ 5 years and 6-10 years groups (9.52 ± 3.16 vs. 9.53 ± 3.19, p = 0.99). In G3.0', 98.2% of cases (54/55) had an image score ≥ 3 and a lesion detection rate of 100% (43/43). The SNR of every age group for G3.0' was comparable to that of G2.0, and no significant differences between ≤ 5 years and 6-10 years groups (9.32 ± 1.94 vs. 9.99 ± 2.28, p = 0.82).

A 2.5 MBq/kg dose with a 3.0 min/bed acquisition protocol is feasible for ¹⁸F-FDG 30-cm SAFOV PET/CT imaging in pediatric patients, and SNR and TLR demonstrated age-dependent discrepancies.