Feasibility Study to Evaluate Therapeutic Ultrasound (TUS) to Acutely Increase the Perfusion in Peripheral Arterial Disease (PAD)

Inclusion Criteria: 1. Age ≥ 65 2. Diagnosis of PAD. 3. Claudication symptoms in Rutherford class 1,2, or 3 as determined by the investigator. Exclusion Criteria: 1. Prior stenting in posterior tibial artery. 2. Re-vascularization procedure within 30 days prior to enrollment in the study. 3. Ulcers, cellulitis, or skin breakdown in treatment areas (posterior calf). 4. History or diagnosis of severe chronic venous insufficiency. 5. Acute limb ischemia within 30 days prior to treatment. 6. History or diagnosis of deep venous thrombosis below the knee in treatment leg. 7. Any conditions that, in the opinion of the investigator, may render the subject unable to complete the study or lead to difficulties for subject compliance with study requirements, or could confound study data. 8. Subject's enrollment in another investigational study that has not completed the required primary endpoint follow-up period. stenting in posterior tibial artery.