RT Journal Article
SR Electronic
T1 Feasibility of an Ultra-Low-Dose PET Scan Protocol with CT-Based and LSO-TX–Based Attenuation Correction Using a Long–Axial-Field-of-View PET/CT Scanner
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP jnumed.124.268380
DO 10.2967/jnumed.124.268380
A1 Sari, Hasan
A1 Teimoorisichani, Mohammadreza
A1 Viscione, Marco
A1 Mingels, Clemens
A1 Seifert, Robert
A1 Shi, Kuangyu
A1 Morris, Michael
A1 Siegel, Eliot
A1 Saboury, Babak
A1 Pyka, Thomas
A1 Rominger, Axel
YR 2025
UL http://jnm.snmjournals.org/content/early/2025/04/10/jnumed.124.268380.abstract
AB Long–axial-field-of-view (LAFOV) PET scanners enable substantial reduction in injected radiotracer activity while maintaining clinically feasible scan times. Whole-body CT scans performed for PET attenuation correction can significantly add to total radiation exposure. We investigated the feasibility of an ultra-low-dose PET protocol and the application of a CT-less PET attenuation correction method (lutetium oxyorthosilicate background transmission [LSO-TX]) that uses 176Lu background radiation from detector scintillators with low-count PET data. Methods: Each of the 4 study subjects was scanned for 90 min using an ultra-low-dose 18F-FDG protocol (injected activity, 6.7–9.0 MBq) with an LAFOV PET scanner. PET images were reconstructed with different frame durations using low-dose CT-based and LSO-TX–based attenuation maps (μ-maps). The image quality of PET images was assessed by the signal-to-noise ratio (SNR) in the liver and the contrast-to-noise ratio in the brain. Absolute errors in SUVs between PET images reconstructed with LSO-TX–based and CT-based μ-maps were assessed at each scan duration. Results: Visual assessment showed that 20–30 min of PET data obtained using 18F-FDG activities below 10 MBq (i.e., 0.1 MBq/kg) can yield high-quality images. PET images reconstructed with CT-based and LSO-TX–based μ-maps had comparable SNRs and contrast-to-noise ratios at all scan durations. The mean ± SD SNRs of PET images reconstructed with the CT-based and the LSO-TX–based μ-maps were 9.2 ± 1.9 dB and 9.8 ± 2.0 dB at 90-min scan duration, 6.8 ± 1.7 dB and 6.9 ± 1.8 dB at 30-min scan duration, and 5.5 ± 1.2 dB and 5.6 ± 1.2 dB at 20-min scan duration, respectively. The relative absolute SUV errors between PET images reconstructed with LSO-TX–based and CT-based μ-maps ranged from 3.1% to 6.4% across different volumes of interest with a 20-min scan duration. Conclusion: PET scans with an LAFOV scanner maintained good visual image quality with 18F-FDG activities below 10 MBq for scan durations of 20–30 min. The LSO-TX–based attenuation correction method yielded images comparable to those obtained with the CT-based attenuation correction method in such protocols.