Testing a New Brain Imaging Tracer for Protein-Related Neurological Diseases

Plain-English translation of NCT06891716 on ClinicalTrials.gov ↗ · Source last updated August 2026 · Translation generated June 2026 · How we translate trials

Phase 1 — Testing in a small group (usually 20–80 people) to find a safe dose and watch for side effects.

What is this trial?

[18F]ACI-19626 is a new radioactive tracer molecule designed to help doctors see and measure harmful protein clumps (called TDP-43) in the brain using PET imaging scans. This trial will test whether the medication is safe and whether it works well enough to detect these protein deposits in people with conditions like frontotemporal dementia and ALS, compared with healthy volunteers.

Currently, doctors cannot easily see TDP-43 protein damage in the living brain—they can only confirm it after death. This medication could help diagnose and track these devastating diseases earlier and more accurately, potentially opening doors to better treatments.

Do you qualify?

You likely qualify if…

you are able to provide informed consent and willing to participate
you are between 40–70 years old (for healthy volunteers)
you have been diagnosed with or show symptoms of frontotemporal dementia, ALS, or related TDP-43 conditions
you are able to lie still in a scanner for up to 90–120 minutes
if you are a woman of childbearing potential, you are willing to use reliable contraception for 30 days after the scan

You likely don't qualify if…

you have a family history of frontotemporal dementia, ALS, or other early-onset neurological disease
you have a significant history of psychiatric or neurological disorders (healthy volunteers only)
you have signs of brain degeneration on an MRI scan done recently
you are a woman of childbearing potential who cannot commit to reliable contraception
you have blood clotting problems or issues that would make it unsafe to place an arterial line

What participation looks like

You will attend 2–3 study visits over about 3 months. At each visit, you will receive an injection of the new radioactive tracer and then have a PET scan, which involves lying still in a scanner for up to 90 minutes while images of your brain are taken. Some participants may have an extra scan about a month later to check how reliable the test is. Blood tests and a physical exam will also be part of the study.

Testing a New Brain Imaging Tracer for Protein-Related Neurological Diseases

What is this trial?

Do you qualify?

What participation looks like

Trial locations(1 site)