The purpose of this feasibility study is to determine if a new emerging technology called photoacoustic tomography (PAT) can be adapted for use in humans for the detection of chronic rheumatoid arthritis.

The objective of this proposal is to adapt photoacoustic tomography (PAT), a novel, nonionizing, noninvasive, laser-based technology, for structural and functional imaging of human peripheral joints affected by inflammatory arthritis.

Combining the advantages of both light and ultrasound scanning, PAT holds promise to present objective optical information in subsurface joint tissues with high sensitivity and high spatial resolution.

This could be of considerable help in the early detection of inflammatory joint diseases. PAT may also prove useful in further understanding the pathophysiology of these disorders and assisting with therapeutic decisions, including assessment of new pharmacological therapies.

In January 2026, the decision was made to reopen recruitment for this study to collect additional data to support future clinical trial work and funding.

Inclusion Criteria:

• Men and women 18 years of age or older can participate in this study.
• Patients can participate in this study if they have had rheumatoid arthritis for more than 2 years and their rheumatologist has referred them to this study.
• Patients can participate as a healthy volunteer with a known history of rheumatoid arthritis.

Exclusion Criteria:

• Patients, who have electrically, magnetically or mechanically activated implants such as heart pacemaker, magnetic surgical clips, prostheses or implanted neurological stimulator.
• Pregnant patients.
• Patients who is claustrophobic.
• Patients with impaired renal function cannot participate in this study such as elevate creatinine clearance, patients on kidney dialysis etc.
• Patients with shock hypotension or unstable low blood pressure.
• Patients with Rhabdomyolysis.
• Patients who have had a contrast enhanced (with gadolinium) MRA (magnetic resonance angiography)/ or MRI within the last 3 months. (Contrast is a medication injected into a vein during a imaging examination that helps produce clearer images/pictures).

Subjects are 1) people who are either healthy volunteers or have patients who have rheumatoid arthritis for more than 2 years and who have a rheumatologist who referred them to this study.