Impact of dead time on quantitative 177 Lu-SPECT (QSPECT) and kidney dosimetry during PRRT.

Autor: Desy A; Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada.; Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada., Bouvet GF; Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada.; Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada., Frezza A; Cancer Research Centre and Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada., Després P; Cancer Research Centre and Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada.; Department of Radiation Oncology and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada., Beauregard JM; Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada. jean-mathieu.beauregard@chudequebec.ca.; Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada. jean-mathieu.beauregard@chudequebec.ca.
Jazyk: angličtina
Zdroj: EJNMMI physics [EJNMMI Phys] 2020 May 15; Vol. 7 (1), pp. 32. Date of Electronic Publication: 2020 May 15.
DOI: 10.1186/s40658-020-00303-0
Abstrakt: Background: Dead time may affect the accuracy of quantitative SPECT (QPSECT), and thus of dosimetry. The aim of this study was to quantify the effect of dead time on 177 Lu-QSPECT and renal dosimetry following peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumours.
Methods: QSPECT/CT was performed on days 1 and 3 during 564 personalized 177 Lu-octreotate cycles in 166 patients. The dead-time data for each scanning time point was compiled. The impact of not correcting QSPECT for the dead time was assessed for the kidney dosimetry. This was also estimated for empiric PRRT by simulating in our cohort a regime of 7.4 GBq/cycle.
Results: The probability to observe a larger dead time increased with the injected activity. A dead-time loss greater than 5% affected 14.4% and 5.7% of QSPECT scans performed at days 1 and 3, respectively. This resulted in renal absorbed dose estimates that would have been underestimated by more than 5% in 5.7% of cycles if no dead-time correction was applied, with a maximum underestimation of 22.1%. In the simulated empiric regime, this potential dose underestimation would have been limited to 6.2%.
Conclusion: Dead-time correction improves the accuracy of dosimetry in 177 Lu radionuclide therapy and is warranted in personalized PRRT.
Databáze: MEDLINE
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