ABSTRACT
This chapter describes the principles and instrumentation behind hybrid imaging with Single-photon emission computed tomography (SPECT)/ Computed tomography (CT). SPECT is technology for creating three-dimensional (3-D) images of the distribution of radioactively labeled substances within a subject. One of the primary uses of CT for cardiac SPECT imaging has been to provide a patient-specific attenuation map for attenuation correction (CT-AC). Software coregistration of a CT scan acquired on a separate scanner can be used to perform CT-AC for SPECT. Half-lives for SPECT isotopes range from hours to days, which facilitates distribution of the isotopes and avoids the need for on-site production facilities. The camera used in SPECT imaging is the gamma camera. Like the parallel-hole collimator, the pinhole collimator still has a tradeoff between resolution and sensitivity with respect to the pinhole diameter. For many years, the most common way to reconstruct 3-D SPECT images was to perform filtered backprojection (FBP).
