Renaud JM, Moody JB & Ficaro EP. Letter to the Editor: Lassen et al. 3D PET/CT ⁸²Rb PET myocardial blood flow quantification: comparison of half‑dose and full‑dose protocols. European Journal of Nuclear Medicine and Molecular Imaging. 2020;47(12):2729–2730.
Description:
This letter to the editor critiques a study by Lassen et al. (2020) that compared full-dose versus half-dose ⁸²Rb PET protocols on 3D PET/CT systems. The original study evaluated the frequency of PET system saturation at standard full-dose protocols (~1,247 ± 196 MBq) and the impact of a reduced, half-dose protocol (~662 ± 115 MBq) on quantitative myocardial blood flow (MBF) estimates.
In their letter, Renaud, Moody, and Ficaro discuss methodological considerations and implications of dose reduction for MBF quantification, particularly in the context of clinical workflow and image quality. They emphasize how saturation effects in full-dose scans may bias flow estimates and support half-dose imaging as a mitigation strategy.
Key Findings:
- Saturation concerns: Approximately 20% of full-dose scans showed saturation artifacts, which were eliminated in half‑dose scans.
- Quantitative consistency: After bias correction, MBF values from half-dose imaging closely matched those from full-dose imaging (MBF_FD ≈ 0.97 mL/g/min vs. corrected MBF_HfD ≈ 0.98 mL/g/min; p = 0.77)
- Protocol recommendation: The authors suggest that half‑dose protocols may prevent saturation-related bias and enhance reliability of MBF quantification in clinical studies.
Clinical Relevance:
This correspondence underscores the importance of calibrating injected dose to scanner performance, especially on 3D PET/CT systems, to avoid bias from saturation effects. Adopting half-dose protocols, with appropriate correction, may ensure more accurate and reproducible MBF measurements in serial and clinical workflows.
