Impact of Ultrahigh Sensitivity and Continuous Bed Motion on Performance Characteristics of Biograph Vision Quadra PET/CT.

Continuous bed motion (CBM) for long-axial-field-of-view PET/CT enables swift total-body examination of patients. However, the sensitivity profile along the axial field of view (AFOV) varies significantly, and its effect on image quality when combined with CBM remains unexplored. This study assesses the effects of ultrahigh sensitivity (UHS) and CBM on recovery coefficients (RCs) and spatial resolution (SR).

Methods

Phantom measurements, performed in static bed and CBM acquisition with different bed speeds (3.5, 7, 14, and 30 mm/s), were reconstructed for both high-sensitivity (HS) and UHS modes, and their quality was assessed using the RC and full width at half maximum of the point-spread function. In addition, 7 clinically referred oncologic patients underwent a combined CBM and UHS [18F]FDG PET/CT scan. Metrics derived from lesions and healthy tissues were compared across acquisition modes.

Results

Mean RC was lower in both UHS (<4.2%) and CBM (<5.9%) than with HS and static acquisitions, respectively. SR in UHS was slightly deteriorated in the central plane of the AFOV (full width at half maximum difference range, 0.06-0.21 mm) but remained comparable toward the edge (full width at half maximum difference range, 0.03-0.07 mm) to SR in HS. In addition, for CBM, SR differences were negligible (full width at half maximum difference, <0.13 mm). SUVs in healthy tissues (r 2 > 0.94) and lesions (r 2 > 0.99) showed excellent correlation. The coefficient of variation was significantly different for the liver.

Conclusion

Elaborate protocols using UHS and CBM could be a step toward swift total-body PET care with only a marginal increase in noise. CBM allows a larger part of the body to be examined and helps to mitigate substantial sensitivity differences along the AFOV, albeit at the cost of slightly lower RC.