Modification and validation of a commercially available portable detector for measurement of adipose tissue blood flow.

Adipose tissue blood flow is measured from the clearance of radioactive xenon from a depot. Traditionally, a NaI detector has been used to measure the residual depot of xenon. However, this is sensitive to movement artefacts. We tested a commercially available lightweight CsI detector which can be strapped to the anterior abdominal wall. In pilot studies the CsI detector produced higher values for adipose tissue blood flow than did a conventional NaI detector. It was modified by inclusion of spacers to distance it from the skin. Flow results generated by the modified detector were similar to those generated by the NaI detector, both after an overnight fast and during the increased blood flow after a meal. Individual decay patterns generated by the CsI detector were, however, significantly smoother than those from the NaI detector.