Purpose: The aim of this retrospective study was to determine, by dynamic acquisition, the optimal scan time of 18F-DOPA PET/CT in patients with recurrent medullary thyroid carcinoma (MTC). Methods: Twenty-one patients with suspected recurrent MTC underwent dynamic 18F-DOPA PET/CT (lasting 45 minutes) followed by whole-body scan. Three different time intervals of dynamic acquisition were evaluated: ultra-early phase (2–5 minutes), early phase (5–10 minutes), and late phase (40–45 minutes). The number and SUVmax of all detected lesions among the 3 dynamic acquisition phaseswere compared on qualitative and semiquantitative analyses. Time-activity curves, SUVmax washout rate between ultraearly or early phase and late phase, and signal-to-noise ratio (SNR) between lesion and background activity were also calculated. Results: At dynamic acquisition, 15 of 21 patients were classified as PETpositive and 6 of 21 as PET-negative, with overall 21 detected lesions. Ultraearly and early imaging provided a better lesion visualization than late phase in more than 70% of cases, as also reflected by SNR (mean SNR reduction between2and45minutes, −45%± 19%). Time-activity curves showed a rapid tracer accumulation inMTClesions,with an average maximum uptake at 2 minutes after injection. Mean lesion SUVmax was 2-fold higher in ultra-early frames compared with last frames (mean washout rate, −44% ± 33%). Finally, compared with whole-body imaging in the same field of view, dynamic acquisition identified 1 additional positive patient and 3 additional lesions in 2 patients. Conclusions: Our study, showing a very fast 18F-DOPA uptake in MTC lesions, suggests the utility to obtain early PET/CT images, already at 2 to 5 minutes after tracer injection, when maximum lesion tracer uptake is reached.

Taralli, S., Lorusso, M., Capotosti, A., Lanni, V., Indovina, L., Rufini, V., Which Is the Optimal Scan Time of 18F-DOPA PET/CT in Patients With Recurrent Medullary Thyroid Carcinoma?: Results From a Dynamic Acquisition Study., <<CLINICAL NUCLEAR MEDICINE>>, 2020; 2020 (45): e134-e140. [doi:10.1097/RLU.0000000000002925] [http://hdl.handle.net/10807/153415]

Which Is the Optimal Scan Time of 18F-DOPA PET/CT in Patients With Recurrent Medullary Thyroid Carcinoma?: Results From a Dynamic Acquisition Study.

Capotosti, A;Lanni, V;Indovina, L;Rufini, V.
2020

Abstract

Purpose: The aim of this retrospective study was to determine, by dynamic acquisition, the optimal scan time of 18F-DOPA PET/CT in patients with recurrent medullary thyroid carcinoma (MTC). Methods: Twenty-one patients with suspected recurrent MTC underwent dynamic 18F-DOPA PET/CT (lasting 45 minutes) followed by whole-body scan. Three different time intervals of dynamic acquisition were evaluated: ultra-early phase (2–5 minutes), early phase (5–10 minutes), and late phase (40–45 minutes). The number and SUVmax of all detected lesions among the 3 dynamic acquisition phaseswere compared on qualitative and semiquantitative analyses. Time-activity curves, SUVmax washout rate between ultraearly or early phase and late phase, and signal-to-noise ratio (SNR) between lesion and background activity were also calculated. Results: At dynamic acquisition, 15 of 21 patients were classified as PETpositive and 6 of 21 as PET-negative, with overall 21 detected lesions. Ultraearly and early imaging provided a better lesion visualization than late phase in more than 70% of cases, as also reflected by SNR (mean SNR reduction between2and45minutes, −45%± 19%). Time-activity curves showed a rapid tracer accumulation inMTClesions,with an average maximum uptake at 2 minutes after injection. Mean lesion SUVmax was 2-fold higher in ultra-early frames compared with last frames (mean washout rate, −44% ± 33%). Finally, compared with whole-body imaging in the same field of view, dynamic acquisition identified 1 additional positive patient and 3 additional lesions in 2 patients. Conclusions: Our study, showing a very fast 18F-DOPA uptake in MTC lesions, suggests the utility to obtain early PET/CT images, already at 2 to 5 minutes after tracer injection, when maximum lesion tracer uptake is reached.
Inglese
Taralli, S., Lorusso, M., Capotosti, A., Lanni, V., Indovina, L., Rufini, V., Which Is the Optimal Scan Time of 18F-DOPA PET/CT in Patients With Recurrent Medullary Thyroid Carcinoma?: Results From a Dynamic Acquisition Study., <<CLINICAL NUCLEAR MEDICINE>>, 2020; 2020 (45): e134-e140. [doi:10.1097/RLU.0000000000002925] [http://hdl.handle.net/10807/153415]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/153415
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