Calibration of an In Vivo Measurement System Using a Voxel Phantom

Although great efforts have been made to improve the physical phantoms used to calibrate in vivo measurement systems, these phantoms represent a single average counting geometry and usually contain a uniform distribution of the radionuclide over the tissue substitute. The calibration method presented here employs a mathematical phantom, produced in the form of volume elements (voxels), obtained through Magnetic Resonance Images (MRI) of the human body. The calibration method uses Monte Carlo techniques to simulate the tissue contamination, to transport the photons through the tissues and to simulate the detection of the radiation. The program transports and detects photons between 0.035 and 2 MeV, and uses a format of 871 'slices' each of 277 x 148 picture elements (pixels) for the body representation.