Three-Dimensional Medical Imaging
Most three-dimensional (3-D) Medical images are generated by using image reconstruction, or tomography, techniques with data from projections that are collected from detectors coupled with various energy sources (Fig. 4.1). These energies can be from X-ray, single-photon emission, positron emission, ultrasound, nuclear magnetic resonance (MR), and light photon. The image so formed is called X-ray-computed tomography (CT, or XCT), single-photon emission tomography (SPECT), positron emission tomography (PET), 3-D ultrasound (3-D US), magnetic resonance imaging (MRI), or 3-D light imaging, respectively. If the projections are 1-D (See Fig. 4.2, left, (Θ)), then the image formed is a 2-D sectional image, f (x, y). A collection of combined multiple sectional images becomes a 3-D image volume. If the projections are 2-D, for example (see Fig. 4.5, (Θ, z)), where z is the body axis, then the reconstruction result will be a fully 3-D image volume.
Recent advances in these techniques produce very large 3-D image volume data. It is not unusual to have hundreds and even thousands of CT or MR images in one examination. Archiving, transmission, display, and management of these large data volume sets become a technical challenge. Refer to Chapter 2, Table 2.1, for the sizes and number of images per examination of these sectional and 3-D imaging modalities.
Since most sectional images, like MRI and CT, are generated based on image reconstruction from ...