Dosimetry of [18F]TRACK, the first PET tracer for imaging of TrkB/C receptors in humans

Alexander Thiel; Alexey Kostikov; Hailey Ahn; Youstina Daoud; Jean-Paul Soucy; Stephan Blinder; Carolin Jaworski; Carmen Wängler; Björn Wängler; Freimut Juengling; Shirin A Enger; Ralf Schirrmacher

doi:10.1186/s41181-023-00219-x

Dosimetry of [¹⁸F]TRACK, the first PET tracer for imaging of TrkB/C receptors in humans

EJNMMI Radiopharm Chem. 2023 Oct 23;8(1):33. doi: 10.1186/s41181-023-00219-x.

Authors

Alexander Thiel^{1

2}, Alexey Kostikov^{3

4

5}, Hailey Ahn^{6

7}, Youstina Daoud^{6

7}, Jean-Paul Soucy^{3

4

8}, Stephan Blinder^{4

8}, Carolin Jaworski⁹, Carmen Wängler¹⁰, Björn Wängler¹¹, Freimut Juengling^{12

13

14}, Shirin A Enger^{6

7}, Ralf Schirrmacher^{9

13}

Affiliations

¹ Jewish General Hospital and Lady Davis Institute for Medical Research, 3755 Chemin de la Cote St. Cathérine, Montreal, Québec, H3T 1E2, Canada. alexander.thiel@mcgill.ca.
² Department of Neurology & Neurosurgery, McGill Univesrity, Montreal, Canada. alexander.thiel@mcgill.ca.
³ Department of Neurology & Neurosurgery, McGill Univesrity, Montreal, Canada.
⁴ Brain Imaging Center, Montreal Neurological Institute, Montreal, Canada.
⁵ Department of Chemistry, McGill University, Montreal, Canada.
⁶ Jewish General Hospital and Lady Davis Institute for Medical Research, 3755 Chemin de la Cote St. Cathérine, Montreal, Québec, H3T 1E2, Canada.
⁷ Medical Physics Unit, McGill University, Montreal, Canada.
⁸ PERFORM Centre Concordia University, Montreal, Canada.
⁹ Cross Cancer Institute, Medical Isotope Cyclotron Facility, University of Alberta, Edmonton, Canada.
¹⁰ Biomedical Chemistry, Clinic of Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
¹¹ Molecular Imaging and Radiochemistry, Clinic of Radiology and Nuclear Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
¹² Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada.
¹³ Department of Oncology, Division of Oncologic Imaging, University of Alberta, Edmonton, Canada.
¹⁴ Medical Faculty, University Bern, Bern, Switzerland.

Abstract

Background: Reduced expression or impaired signalling of tropomyosin receptor kinases (Trk receptors) are found in a vast spectrum of CNS disorders. [¹⁸F]TRACK is the first PET radioligand for TrkB/C with proven in vivo brain penetration and on-target specific signal. Here we report dosimetry data for [¹⁸F]TRACK in healthy humans. 6 healthy participants (age 22-61 y, 3 female) were scanned on a General Electric Discovery PET/CT 690 scanner. [¹⁸F]TRACK was synthesized with high molar activities (A_m = 250 ± 75 GBq/µmol), and a dynamic series of 12 whole-body scans were acquired after injection of 129 to 147 MBq of the tracer. Images were reconstructed with standard corrections using the manufacturer's OSEM algorithm. Tracer concentration time-activity curves (TACs) were obtained using CT-derived volumes-of-interest. Organ-specific doses and the total effective dose were estimated using the Committee on Medical Internal Radiation Dose equation for adults and tabulated Source tissue values (S values).

Results: Average organ absorbed dose was highest for liver and gall bladder with 6.1E-2 (± 1.06E-2) mGy/MBq and 4.6 (± 1.18E-2) mGy/MBq, respectively. Total detriment weighted effective dose E_DW was 1.63E-2 ± 1.68E-3 mSv/MBq. Organ-specific TACs indicated predominantly hepatic tracer elimination.

Conclusion: Total and organ-specific effective doses for [¹⁸F]TRACK are low and the dosimetry profile is similar to other ¹⁸F-labelled radio tracers currently used in clinical settings.

Keywords: Dosimetry; Positron emission tomography; Tropomyosin receptor kinases; [18F]TRACK.

Grants and funding

PJT169049/Canadian Institutes for Health Research (CIHR)