Evaluation of [68Ga]Ga-PSMA PET/CT Images Acquired with a Reduced Scan Time Duration in Prostate Cancer Patients Using the Digital Biograph Vision - Beyond the Abstract

PET imaging using PSMA-ligands has been shown to outperform conventional imaging, such as MRI, CT, and bone scintigraphy. It is particularly advantageous in the setting of biochemical recurrence with low tumor burden. Unfortunately, the availability of PSMA is limited by 68Ga/68Ge generator yield and to a lesser degree scan time.

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

  1. 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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