Three-dimensional reconstruction of isotope distributions

In the patient scanning situation with a parallel-hole collimator, it is possible to obtain a quantitative solution for the gamma emitter distribution, if attenuation is included in the calculation. Using the iterative least squares method, the distribution in a transverse section is calculated, then this distribution is modified by exp (+ mu x), where x is the distance between each point in the reconstructed section, and the object's boundary, and mu is a known or assumed attenuation coefficient. This approach works for energies of 99Tcm (140 keV) and above ( mu =0.14 cm-1).