Single Photon Emission Computed Tomography (SPECT)

Although the principles of single photon emission computed tomography (SPECT) have been well understood for many years and several centers were using SPECT clinically in the late 1960s and early 1970s, there has been a dramatic increase in the number of SPECT installations in recent years. It is now unusual to purchase a gamma camera without SPECT capability and most new cameras are dual-headed, which can offer additional advantages in SPECT. A state-of-the-art gammacamera that iswell maintained should produce high-quality SPECT images consistently, and even older cameras can produce acceptable images if care is taken. SPECT is essential for imaging the brain with either cerebral blood flow agents, such as ^99mTc-HMPAO, or brain receptors, such as ¹²³I-FP-CIT, and for imaging myocardial perfusion with either ²⁰¹Tl or the technetium-labeled agents MIBI and tetrofosmin. SPECT is also now widely used in some aspects of skeletal imaging and can be helpful in tumor imaging with, for example, ¹²³I-MIBG, ¹¹¹In octreotide, or ^99mTc NeoSPECT.