We used a new and easy-to-measure iPad 3D scanner to measure swelling in lower limbs because current technology is not easily available or affordable. We want to see how reliable the measurements are and what might affect how consistent they are.

Twenty limbs from ten healthy volunteers were scanned using an iPad-based Structure Sensor and software. Initial scans followed standard manufacturer instructions, but high variance rendered data unsuitable for clinical use. To improve accuracy, a standardized scanning protocol was developed, incorporating anatomical calibration, scanning distance standardization, and scanning time control. A 254-mm calf segment was defined using a 3D marker placed on the medial malleolus to ensure consistent volume measurement. The scanning distance was fixed between 50-59 cm to reduce zoom parallax errors, and scans were conducted after 3 PM to minimize diurnal volume fluctuations. Multiple technicians performed repeat scans on the same limb to assess intra-observer and inter-observer scan reliability.

Inclusion Criteria:

• The people in this study will be symptom free volunteers.

Exclusion Criteria:

• Pre-existing diseased limbs

The target population will be symptom-free volunteers in order to establish a method of scanning for the best results. Volunteers in this study will have no coercion involved.

The consent form clearly states that "We will not collect any protected health information in this study. Data collected will be as following: sex, age, weight, and volume of limbs." Therefore, there is no risk to patient confidentiality.