Stimulated Positron Emission Tomography Techniques for the Quantitative Assessment of Fluorine in Bone

The use of nuclear photoactivation in conjunction with positron emission analysis techniques to quantify the spatial distribution of elements in bone is considered. A realistic model of bone composition and a simplified model of bremsstrahlung spectral intensity have been used to calculate the activation yields obtainable with medical linear accelerators. The results of activation experiments performed using a linac-produced 18-MV X-ray beam have been compared with the predictions of this model to assess the feasibility of obtaining the relative amounts of the different elements from the analysis of the time dependence of the decay. It is concluded that photonuclear activation in conjunction with positron emission analysis techniques has the potential for noninvasively determining the elemental composition of bone. Because this process will also have the unique signature used in positron emission tomography (PET), it provides an approach to imaging the distribution of elements within bones