Abstract Quantitative PET studies require a measurement of the arterial input function (AIF), the time-dependent radiotracer concentration in arterial blood plasma. Several groups are developing non-invasive detectors to measure the AIF from the radial artery. This study quantifies the depth and cross-sectional area of the radial artery and accompanying veins at different wrist positions using ultrasound. These anatomical data will guide the design of a non-invasive, wrist-worn detector for AIF acquisition—a practical, patient-friendly alternative to invasive blood sampling. Ultrasound imaging of the wrist was performed on 154 healthy individuals at specified distances from the distal wrist crease (2 cm, 4 cm, and 6 cm). The depths of the radial artery at distances of 2 cm, 4 cm, and 6 cm from the distal wrist crease are 3. 36 (1. 25) mm, 4. 08 (1. 81) mm, and 4. 66 (2. 23) mm, respectively (mean (SD) ). Similarly, the cross-sectional areas of the radial artery at these distances are 4. 23 (1. 75) mm ^2, 3. 92 (1. 71) mm ^2, and 3. 90 (1. 88) mm ^2, respectively. The radial artery becomes larger and more superficial near the wrist, suggesting a radiation detector be placed 2 cm from the distal wrist crease on the left arm, where it is generally more superficial than on the right.
Leclerc et al. (Sun,) studied this question.