Nuclear Cardiology Technology (NCT)
Core concepts
The NCT specialty centers on myocardial perfusion imaging, ventricular function, and the physics of cardiac SPECT and PET. Expect questions on Tc-99m sestamibi and tetrofosmin, thallium-201, stress agents, gating, and image processing.
Know perfusion patterns: reversible defect suggests ischemia; fixed defect suggests scar or infarction; reverse redistribution and transient ischemic dilation are recognized patterns. Thallium behaves as a potassium analog and redistributes; sestamibi and tetrofosmin have minimal redistribution, so rest and stress are acquired separately.
Stress and safety
Exercise stress versus pharmacologic stress (adenosine, regadenoson, dipyridamole, dobutamine) each has contraindications. Caffeine and methylxanthines block adenosine receptors; bronchospasm and high-grade AV block are cautions. Know when dobutamine is preferred over vasodilators.
Acquisition and processing
Understand gated SPECT for ejection fraction and wall motion, ECG gating requirements, and the importance of a regular rhythm. Patient positioning, breast attenuation, diaphragmatic attenuation, and patient motion produce artifacts that mimic defects. Prone or attenuation-corrected imaging can resolve them.
Rule of thumb
A defect that improves or disappears on the rest or redistribution image is ischemic; one that persists is scarred. Use this pattern rule to triage most perfusion questions.