A potential strategy to expand the availability of PSMA-PET includes the use of 18F-based tracers. These have generally shown a good diagnostic performance; however, unspecific (“false-positive) uptake in benign lesions has been shown to be much more common than in 68Ga-PSMA making caution warranted.1
The advent of a new generation of Si-Pm based “digital” PET devices offers the prospect of reducing scan times or administered activities due to improved detector sensitivity and thus allows for an expansion of PSMA-PET availability.
Our results indicate that a dose reduction is potentially feasible but leads to a slight reduction in the detection of small lesions. As the detection of small lesions is one of the key advantages of PSMA-PET over conventional imaging, a blanket recommendation to implement low-activity protocols cannot be made based on our results.
However, in patients, in whom missing small metastases might not lead to changes in management, such as those scheduled for PSMA-targeted radioligand therapy, a reduction in administered activity can be considered. This is supported by the high agreement of image quantification between images acquired with regular scan time vs. those acquired with a 3.5-fold reduced scan time. This was particularly true for images reconstructed with 2 iterations.
Written by: Manuel Weber, Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK)-University Hospital Essen, Hufelandstrasse, Essen, Germany
- Rauscher I, Kronke M, Konig M, et al. Matched-Pair Comparison of (68)Ga-PSMA-11 PET/CT and (18)F-PSMA-1007 PET/CT: Frequency of Pitfalls and Detection Efficacy in Biochemical Recurrence After Radical Prostatectomy. J Nucl Med. 2020;61:51-57.
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