This is a Phase 1, single-center, open-label study evaluating the safety, biodistribution, and radiation dosimetry of Radiocaine™, an investigational fluorine-18-labeled PET radiotracer designed to bind voltage-gated sodium channels. The study enrolls adult volunteers and aims to inform future clinical development in molecular imaging applications. Radiocaine™ is being developed as a potential diagnostic imaging agent and imaging biomarker for the localization and quantification of sodium channel activity.

This is a Phase 1, single-center, open-label study evaluating the safety, biodistribution, and radiation dosimetry of Radiocaine™, an investigational fluorine-18-labeled PET radiotracer designed to bind voltage-gated sodium channels.

The study will enroll six healthy adult volunteers, each of whom will receive a single intravenous dose of Radiocaine™. Serial PET/MR imaging will be performed over several hours post-injection to assess the distribution of the radiotracer in various tissues and organs. Blood and urine samples will be collected at predefined timepoints to support pharmacokinetic and dosimetry modeling. Safety assessments, including vital signs, laboratory tests, and monitoring for adverse events, will be conducted throughout the study.

The primary objectives are to:

• Evaluate the safety and tolerability of a single dose of Radiocaine™ in adults;
• Characterize the biodistribution of Radiocaine™ in key organs and tissues;
• Estimate radiation exposure (dosimetry) to inform future clinical use.

These data will guide dosing strategies, image acquisition timing, and safety parameters for future clinical studies. The results will also support the further development of Radiocaine™ as a potential diagnostic imaging agent and molecular imaging biomarker for the localization and quantification of sodium channel activity in human subjects.

This study is intended for early-stage characterization of Radiocaine™ in preparation for future clinical studies in disease-specific populations.

Inclusion Criteria:

• 18 years and older
• Able to provide written consent
• Willing and able to undergo ECG, imaging, blood sampling, and complete self-assessment rating scales at the specified time points
• Unremarkable baseline health without report of chronic or acute pain
• Willing and able to participate in all imaging procedures and complete the self-assessment rating scales at the specified time points

Exclusion Criteria:

• Body mass index (BMI) of 32 or greater, weight >300 lbs
• Diagnosis of severe depression/anxiety (PROMIS score > 95%) or suicidal ideation
• History of opioid abuse or opioid use disorder
• History of seizures or epilepsy
• History of major Axis I or Axis II psychiatric disorder that might, in the opinion of the investigator, make it difficult for the subject to complete all the procedures (e.g. obsessive-compulsive disorder, bipolar disorder, schizophrenia, or schizoaffective disorder)
• History of cardiac arrhythmia
• History of major orthopedic surgery within the last 12 months
• Recent history (previous 6 months) of sodium channel blocker use, including, but not limited to: carbamazepine, lamotrigine, lidocaine, phenytoin, propranolol, or valproate
• Any significant systemic illness or medical condition that could lead to difficulty complying with the study protocol
• Creatinine clearance (calculated using the Cockcroft-Gault formula or measured) < 60 mL/min or serum creatinine >1.5 x ULN
• QTcF >470 msec for females and QTcF >450 msec for males on screening ECG
• MRI-incompatible implants, large tattoos, previous shrapnel injury
• Pregnancy or lactating
• History of contact sport participation, such as football, hockey, or rugby
• Known claustrophobia related to MR or PET-MRI scanners
• Recent blood donation/draw of >1 unit (previous 4 weeks)
• History of hypersensitivity to local anesthetics of the amide type
• Family or personal history of familial malignant hyperthermia