FACTORS AFFECTING IN VIVO X-RAY FLUORESCENCE MEASUREMENTS OF LEAD IN BONE.

The factors affecting the sensitivity of X-ray fluorescence determination of lead in bone phantoms using **5**7Co are investigated with the object of applying the technique to in vivo measurements in tibia. An analysis of the components of the measured pulse height spectrum in a hyperpure Ge detector is presented and the implications for the optimization of the source-detector configuration discussed. Finally, Some preliminary investigations using a **1**0**9Cd source are outlined.