Radiocaine Safety Study

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
* 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