Scan-time reduction using noise-matched images in 2- and 3-dimensional bismuth germanate PET/CT : clinical study in head and neck cancer

Wequantitativelyandqualitativelyinvestigated2-dimensional(2D) and3-dimensional(3D)imagingwithscan-timereductionin14patientswith17lesions,whohadknownorsuspectedheadandneck cancer, using a bismuth germanate (BGO) crystal based PET/CT scanner with noise-matched images. Methods: A 2D and 3D acquisition protocol using scan-time reduction on an axial single field of view resulted in a 2D 4-, 3D 4-, 3D 3-, 2D 3-, 2D 2-, and 3D 2-min scan sequence to minimize redistribution and decay bias. Tumor maximum standardized uptake values (SUVmax) and tumor mean standardized uptake values (SUVmean) were recorded, and two observers in consensus investigated lesion conspicuity between 2D and 3D paired 4-, 3-, and 2-min noisematched images. Results: We found some minor advantages quantitativelyinfavorof2Dscanning,withhighermeanSUVmax, and qualitatively in favor of 3D scanning, with lesion conspicuity preference. In our cohort, no great advantage or disadvantage to using either acquisition mode was observed, and all lesions were seen irrespective of acquisition mode and scan time. Conclusion: In head and neck cancer patients, we can recommend a scan-time reduction from 4 to 3 min/bed position in 2D acquisitions with a BGO-based PET/CT scanner, using our imaging protocol and reconstruction defaults.