Photon scattering in biomedically important elements

Abstract

A survey of recently published work on the biomedical and other applications of the ratios of coherent to incoherent scattering of gamma radiation off low Z elements has revealed that the functional dependence of any individual process is, for the most part, misrepresented. It is shown, by analysis of the available tabulated coherent and incoherent scattering functions, that an explicit power dependence of Z may not be easily expressed. Furthermore, Rayleigh scattering is much better represented by the modified form factor rather than the usual form factor approach. The quantities of interest in using the coherent to incoherent scattering intensity ratio have been identified and various parametrical procedures have been developed within the range of atomic number and momentum transfers of biomedical interest. Applications to bone mineral measurements are discussed and future investigations based upon recent, more accurate theoretical predictions of scattering cross-sections are suggested.

Coherent scatter computed tomography: a novel medical imaging technique

“…Coherent scattering has a distinct structure, characteristic of each type of material. In the structure function approximation, the cross-section for coherent scattering is given by 19,20 (…”

“…In Figure 1 the coherent scatter cross-sections of water, tendon (containing collagen), fat and bone (containing tricalcium phosphate) are given, materials found in the human body 19 . …”

Scattering in uniform media (for correction of nuclear medicine images)

“…Compton (incoherent) scatter up to order 18 Coherent scatter up to order 5 Photoelectric effect Lead x-ray production Compton scatter was described by the Klein-Nishina differential cross section for unpolarised radiation (Bradley andGhose 1984, Evans 1955) while the coherent scatter differential cross section has been described by Williamson and Morin as well as by Neitzel et a1 (Williamson andMorin 1983a, b, Neitzel e? a1 1985).…”