Gamma Scintigraphy and SPECT

Gamma scintigraphy provides powerful images that show how dosage forms behave in the body. This chapter is concerned with the radionuclide imaging techniques of gamma scintigraphy and single-photon emission computed tomography (SPECT), which are used widely to assess drug delivery by various routes. It focuses on the role of the single-photon imaging techniques of γ-scintigraphy and SPECT. Gamma scintigraphy and SPECT are both methods that provide quantitative information about the behavior of pharmaceutical dosage forms. In some situations, the additional three-dimensional information provided by SPECT is probably of little value. In order to illustrate the use of two-dimensional γ-scintigraphy and three-dimensional SPECT, a series of case studies will be presented involving pulmonary, nasal, and gastrointestinal drug delivery. Since SPECT involves the acquisition of multiple images, the entire SPECT procedure typically takes longer than planar imaging, and it is important that the radionuclide distribution should remain essentially static during the imaging process.