ABSTRACT
Medical imaging utilizes several different physical principles or imaging modalities. The common modalities used clinically include x-ray, computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging, and ultrasound. Reconstructed images from PET, SPECT, and CT all use collimated beams directed through the target, but they vary in the mechanism used to produce these beams. Filtered back projection can be described in either the spatial or spatial frequency domain. The MATLAB Image Processing Toolbox contains routines that perform both the Radon and inverse Radon transforms in both parallel and fan beam configurations. MRI images can be acquired in a number of ways using different image acquisition protocols. A basic demonstration of fMRI analysis can be provided using standard MATLAB routines. Different imaging modalities are based on different physical principles. In MRI, tissue protons have their spins aligned by a very strong magnetic field.
