Comparison of prone versus supine 18F‐FDG‐PET of locally advanced breast cancer: Phantom and preliminary clinical studies

Abstract

Purpose: Previous studies have demonstrated how imaging of the breast with patients lying prone using a supportive positioning device markedly facilitates longitudinal and/or multimodal image registration. In this contribution, the authors' primary objective was to determine if there are differences in the standardized uptake value (SUV) derived from [ 18 F]fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in breast tumors imaged in the standard supine position and in the prone position using a specialized positioning device. Methods: A custom positioning device was constructed to allow for breast scanning in the prone position. Rigid and nonrigid phantom studies evaluated differences in prone and supine PET. Clinical studies comprised 18F-FDG-PET of 34 patients with locally advanced breast cancer imaged in the prone position (with the custom support) followed by imaging in the supine position (without the support). Mean and maximum values (SUV peak and SUV max , respectively) were obtained from tumor regions-of-interest for both positions. Prone and supine SUV were linearly corrected to account for the differences in 18F-FDG uptake time. Correlation, Bland-Altman, and nonparametric analyses were performed on uptake time-corrected and uncorrected data. Results: SUV from the rigid PET breast phantom imaged in the prone position with the support device was 1.9% lower than without the support device. In the nonrigid PET breast phantom, prone SUV with the support device was 5.0% lower than supine SUV without the support device. In patients, the median (range) difference in uptake time between prone and supine scans was 16.4 min (13.4-30.9 min), which was significantly-but not completely-reduced by the linear correction method. SUV peak and SUV max from prone versus supine scans were highly correlated, with concordance correlation coefficients of 0.91 and 0.90, respectively. Prone SUV peak and SUV max were significantly lower than supine in both original and uptake time-adjusted data across a range of index times (P << 0.0001, Wilcoxon signed rank test). Before correcting for uptake time differences, Bland-Altman analyses revealed proportional bias between prone and supine measurements (SUV peak and SUV max ) that increased with higher levels of FDG uptake. After uptake time correction, this bias was significantly reduced (P < 0.01). Significant prone-supine differences, with regard to the spatial distribution of lesions relative to isocenter, were observed between the two scan positions, but this was poorly correlated with the residual (uptake time-corrected) prone-supine SUV peak difference (P = 0.78).Conclusions: Quantitative 18F-FDG-PET/CT of the breast in the prone position is not deleteriously affected by the support device but yields SUV that is consistently lower than those obtained in the standard supine position. SUV differences between scans arising from FDG uptake time differences can be substantially reduced, but not removed entirely, with the current correction method. SUV from the two sca...

Evaluation of image quality at the detector’s edge of dedicated breast positron emission tomography

“…In this study, we quantitatively evaluated TOF-reconstructed PET/CT images, since edge artefacts are known to occur in PSF modelling during reconstruction and are significant for small lesions [ 33 ]. Furthermore, some reports have shown that visualisation of small breast lesions can be improved by performing PET/CT in the prone position using assistive devices to allow breast expansion and suppression of respiratory movements [ 34 , 35 ]. PET technologies, such as TOF and PSF, smaller pixel sizes, and prone position scanning, are expected to improve the visual detection rate of smaller lesions using PET/CT.…”

Evaluation of image quality at the detector’s edge of dedicated breast positron emission tomography

“…In this study, we quantitatively evaluated TOF-reconstructed PET/CT images, since edge artefacts are known to occur in PSF reconstruction and are signi cant for small lesions [30]. Furthermore, some reports have shown that visualisation of small breast lesions can be improved by performing PET/CT in the prone position using assistive devices to allow breast expansion and suppression of respiratory movements [31,32]. PET technologies, such as TOF and PSF, smaller pixel sizes, and prone position scanning, are expected to improve the visual detection rate of smaller lesions using PET/CT.…”

Towards real-time topical detection and characterization of FDG dose infiltration prior to PET imaging

“…Sensors operated in 2-second cycles: 1 second to count the activity followed by 1 second to record the data. Near the end of the uptake period (42 – 59 min post-FDG) sensors were removed, and patients underwent limited whole-body PET/CT (i.e., top-of-skull to mid-thigh FOV) in a Discovery STE scanner (GE Healthcare, Waukesha, WI, USA) as previously described [10]. …”