Digital PET systems (dPET) improve lesion detectability as compared to PET systems with conventional photomultiplier tubes (cPET). We prospectively studied the performance of high-resolution digital PET scans in patients with cancer, as compared with high- and standard-resolution conventional PET scans, taking the acquisition order into account.
We included 212 patients with cancer, who were referred for disease staging or restaging. All patients underwent FDG-PET/CT on a dPET scanner and on a cPET scanner in a randomized order. The scans were acquired immediately after each other. Three image reconstructions were generated: 1) standard-resolution (4 × 4 × 4 mm3 voxels) cPET, 2) high-resolution (2 × 2 × 2 mm3 voxels) cPET, and 3) high-resolution dPET. Two experienced PET readers visually assessed the three reconstructions side-by-side and ranked them according to scan preference, in an independent and blinded fashion.
On high-resolution dPET, the PET readers detected more lesions or they had a higher diagnostic confidence than on high- and standard-resolution cPET (p < 0.001). High-resolution dPET was preferred in 90% of the cases, as compared to 44% for high-resolution cPET and 1% for standard-resolution cPET (p < 0.001). However, for the subgroup of patients where dPET was made first (n = 103, 61 ± 10 min after FDG administration) and cPET was made second (93 ± 15 min after FDG administration), no significant difference in preference was found between the high-resolution cPET and dPET reconstructions (p = 0.41).
DPET scanners in combination with high-resolution reconstructions clinically outperform cPET scanners with both high- and standard-resolution reconstructions as the PET readers identified more FDG-avid lesions, their diagnostic confidence was increased, and they visually preferred dPET. However, when dPET was made first, high-resolution dPET and high-resolution cPET showed similar performance, indicating the positive effect of a prolonged FDG uptake time. Therefore, high-resolution cPET in combination with a prolonged FDG uptake time can be considered as an alternative.
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Fluorodeoxoglucose-positron emission tomography/computed tomography
2 × 2 × 2 mm3 voxel reconstructions
4 × 4 × 4 mm3 voxel reconstructions
Digital PET scan was made first, conventional PET scan was made second
Conventional PET scan was made first, digital PET scan was made second
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We thank Tessa Gerritse and Ellis Simons-Winters for their assistance in patient inclusion. Further, we thank the staff from Isala, Zwolle for their overall support.
This work was supported by a research collaboration regarding new PET technologies between the Department of Nuclear Medicine, Isala hospital and Philips Healthcare. The content of the article was solely the responsibility of the authors.
Conflict of interest
There are no other potential conflicts of interest.
All participants gave written informed consent. The Medical Ethical Committee of our institute (METC Isala, Zwolle, the Netherlands) approved the study protocol (NL52329.075.15) and the study was registered at clinicaltrials.gov with identifier NCT03457506.
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de Jong, T.L., Koopman, D., van Dalen, J.A. et al. Performance of digital PET/CT compared with conventional PET/CT in oncologic patients: a prospective comparison study. Ann Nucl Med 36, 756–764 (2022). https://doi.org/10.1007/s12149-022-01758-0
- Digital PET
- Conventional PET
- Lesion detection