Radiation Dosimetry of the 18 kDa Translocator Protein Ligand [18F]PBR111 in Humans

NCT06398392 | Completed DMC

• 1 other identifier: 2022-00542
• Study Type: interventional
• Target: 6
• Locations: 1 country
• Sites: 1

Brief Summary

The 18 kDa translocator protein (TSPO) is a mitochondrial protein that becomes overexpressed during neuroinflammatory conditions, such as in Alzheimer's disease or multiple sclerosis. TSPO is of interest because it serves as a marker for microglial and astrocytic activity, measurable via in vivo positron emission tomography (PET) molecular imaging. \[18F\]PBR111 is a second-generation TSPO PET radioligand with high signal specificity but a sensitivity to TSPO polymorphism, in comparison with first-generation ligands. This study focused on the biodistribution and dosimetry of \[18F\]PBR111 in healthy humans.

Conditions

Dosimetry; Healthy

Outcome Measures

Primary Outcomes (1)

• Measurement of radiation dosimetry and biodistribution of the translocator protein radiotracer [18F]PBR111 determined with PET/CT in healthy human volunteers (3 male and 3 female participants)

  \[18F\]PBR111 will be manually injected as a smooth bolus followed by a 20-ml saline flush via an intravenous catheter in the antecubital fossa placed before the scan. After injecting a standard \[18F\]PBR111 activity of 200 MBq, PET/CT scans will be performed on a BiographTM mCT or Vision scanner (Siemens Healthcare, Erlangen, Germany). The whole duration of the scanning protocol is about 120 minutes, consisting of CT and PET dynamic acquisitions.

  6 months

Secondary Outcomes (1)

• Calculation of the total radiation exposure of a PET/CT with 200 MBq of [18F]PBR111

  6 months

Study Arms (1)

Drug: radiation dosimetry and biodistribution

EXPERIMENTAL

6 healthy adult volunteers (3 men and 3 women) will be assigned to the radiation dosimetry group. \[18F\]PBR111 will be administered once.

Drug: [18F]PBR111; Procedure: PBR111 injection; Device: PET scan; Radiation: PBR111 dosimetry

Interventions

[18F]PBR111 DRUG

\[18F\]PBR111 is a radiotracer produced at University Hospital of Geneva in a radiopharmaceutical GMP facility. The drug product is provided as sterile solution for intravenous injection in a glass vial containing 10 mL (max) of formulated product, the maximal applicable dose being 200 MBq.

Also known as: Preparation

Drug: radiation dosimetry and biodistribution

PBR111 injection PROCEDURE

\[18F\]PBR111 will be administered once, intravenously in the antecubital fossa at a dose of 200 MBq

Drug: radiation dosimetry and biodistribution

PET scan DEVICE

Upon administration of the radiotracer, a 120-minute PET/CT scan will be initiated.

Drug: radiation dosimetry and biodistribution

PBR111 dosimetry RADIATION

to establish the exposure of the organs/tissues to a standard radioactive dose (200 MBq) of \[18F\]PBR111

Drug: radiation dosimetry and biodistribution

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged ≥18 (3 male and 3 female participants)
• Fluent in French and able and willing to provide written informed consent.

You may not qualify if:

• Homozygosity for the rs6971 polymorphism on TSPO that results in low-affinity binding. This criterion is added because this polymorphism alters significantly the ability of the radiotracer \[18F\]PBR111 to bind to TSPO, hence precluding quantification.
• Absence of a stable contraceptive regimen (specifically, intrauterine contraceptive device or contraceptive treatment per os). Only women with stable contraception will be added to eliminate the risk of exposure of pregnant women and their foetus to radioactivity.
• Presence of any significant history or current diagnosis of chronic disease or syndrome (including neurological, psychiatric, cardiovascular, oncological, metabolic, rheumatological conditions).
• Presence of clinically relevant laboratory abnormalities in the haematological and biochemical blood tests, as defined as laboratory values that require clinical workup and/or treatment (e.g. anaemia, hyperglycaemia, electrolyte imbalances)
• A body mass index \<20 or \>30 (this criterion is necessary because TSPO has been shown to be variable with respect to body mass index (113-115)).
• Exposure to research related radiation in the past five years that, when combined with this study, would place subjects above the allowable limits.
• Conditions precluding entry into the scanners (e.g. claustrophobia).

Sponsors & Collaborators

• Prof. Daniele Zullino: lead

Study Sites (1)

Geneva University Hospital

Geneva, Switzerland

Location

Related Publications (1)

• Tournier BB, Mansouri Z, Salimi Y, Ceyzeriat K, Mathoux G, Richard-Lepouriel H, Zullino D, Bois F, Zaidi H, Garibotto V, Tsartsalis S, Millet P. Radiation dosimetry of the 18 kDa translocator protein ligand [18F]PBR111 in humans. Nucl Med Biol. 2025 May-Jun;144-145:109011. doi: 10.1016/j.nucmedbio.2025.109011. Epub 2025 Mar 29.

  PMID: 40179687 BACKGROUND

MeSH Terms

Interventions

2-(6-chloro-2-(4-(3-fluoropropoxy)phenyl)imidazo(1,2-a)pyridin-3-yl)-N,N-diethylacetamide; Positron-Emission Tomography

Intervention Hierarchy (Ancestors)

Tomography, Emission-Computed; Image Interpretation, Computer-Assisted; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis; Image Enhancement; Photography; Radionuclide Imaging; Tomography; Diagnostic Techniques, Radioisotope

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Professor Daniele Zullino

Study Record Dates

• First Submitted: April 23, 2024
• First Posted: May 3, 2024
• Study Start: June 24, 2024
• Primary Completion: July 30, 2024
• Study Completion: July 30, 2024
• Last Updated: September 16, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)