Spherical Geometry in Medical Imaging

Assume that energy (sound, light, heat, or radiation) is radiating uniformly in all directions from a point source, with a detector of a known size and shape at a given distance away. We are interested in determining how much of the energy emitted strikes the face of the detector. Our particular application is to medical imaging. After absorbing a radioactive substance via a venous injection, a structure such as a small tumor becomes radioactive and can be considered a point source. A detector is then placed in position to meive emitted energy.