ABSTRACT
Nuclear medicine images demonstrate function, rather than anatomy. Some of the limitations of nuclear medicine imaging studies include limited spatial resolution, poor signal-to-noise ratio, and frequently poor uptake of the radiotracer in the diseased condition. Registration with a structural or anatomical image can be useful in addressing a number of these issues. The main applications at present are
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Intramodality and intermodality spatial registration
—intramodality registration in positron emission tomography (PET) and single photon emission computed tomography (SPECT), e.g., PET-PET, SPECT-SPECT, and intermodality registration with other functional or structural data such as from x-ray CT and magnetic resonance imaging (MRI), e.g., PET-MRI
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Correcting nuclear medicine emission data
—correction for photon attenuation and scattering, partial volume correction to compensate for limited spatial resolution, and guiding image reconstruction algorithms where anatomical priors can be used to “encourage” a reconstruction towards a particular solution, based on the known biodistribution of the radiotracer
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Intersubject registration (spatial normalization)
—standardizing the geometric conformation of uptake in an organ for comparisons with normal databases or for use in cohort studies
The methods used to achieve the above, and examples of their use, are the subject of this chapter. Some discussion of MR-PET registration is included here, but this topic is treated in more detail in Chapter 9.
