SPECT (Single Photon Emission Computed Tomography)
Nuclear medicine tomographic imaging that provides detailed 3D images of organ function and blood flow.
What is SPECT?
SPECT (Single Photon Emission Computed Tomography) is a nuclear medicine imaging technique that uses gamma rays to create 3D images of functional processes in the body. Unlike conventional CT or MRI that show anatomy, SPECT demonstrates how organs are functioning at the cellular level.
How it works: The procedure involves administering a small amount of radioactive tracer that is absorbed by specific organs or tissues. Special gamma cameras rotate around the patient to detect the gamma rays emitted by the tracer. A computer then reconstructs these signals into detailed cross-sectional images showing blood flow, metabolism, and other functional parameters.
Common Uses of SPECT
Cardiac Stress Testing
Evaluates coronary artery disease and myocardial perfusion at rest and during stress exercise or pharmacologic stimulation.
Epilepsy Localization
Identifies seizure foci in the brain for surgical planning and treatment of refractory epilepsy.
Tumor Detection and Response
Assesses tumor metabolism, detects metastases, and monitors response to therapy in various cancers.
Advantages
- ✓Functional assessment showing organ physiology
- ✓High sensitivity for detecting metabolic changes
- ✓Can evaluate disease activity before structural changes occur
- ✓Relatively non-invasive with minimal discomfort
- ✓Widely available and relatively cost-effective
Limitations
- ⚠Lower spatial resolution than CT or MRI
- ⚠Longer imaging time than other modalities
- ⚠Requires patient cooperation for optimal results
- ⚠Limited by patient size and body habitus
- ⚠Some overlap in tracer uptake patterns
Preparation Checklist
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⚖️SPECT vs CT
Related Imaging Modalities
Often combined with CT for anatomical correlation (SPECT/CT) or MRI for detailed soft tissue evaluation.
CT
CT scans use X-rays to create detailed cross-sectional images of the body. They are particularly useful for detecting bone fractures, tumors, and internal bleeding.
MRI
MRI uses powerful magnets and radio waves to produce detailed images of organs and soft tissues. Excellent for brain, spine, and joint imaging.
Ultrasound
Ultrasound uses sound waves to create real-time images. Commonly used for pregnancy monitoring and examining organs like the heart, liver, and kidneys.
Browse SPECT Terms
Explore common terms in SPECT reports, each with detailed explanations, clinical significance, and related lab tests to help you understand your imaging results. lab tests.
Brain Perfusion SPECT: What It Shows, Cost & Preparation
Areas of decreased or increased radiotracer uptake corresponding to regional cerebral blood flow. Focal defects indicate stroke, tumor, or trauma. Diffuse patterns suggest neurodegenerative disease. Frontal/temporal hypoperfusion suggests dementia.
Myocardial Perfusion SPECT: What It Shows, Cost & Preparatio
Reversible perfusion defects indicate ischemia. Fixed defects suggest scar/infarction. Stress-induced ischemia shows reduced tracer uptake during stress with normalization at rest. Wall motion abnormalities and transient ischemic dilation may be present.
Parathyroid Adenoma SPECT: What It Shows, Cost & Preparation
Focal area of increased radiotracer uptake corresponding to parathyroid adenoma. Early thyroid-phase images show thyroid and parathyroid activity together. Delayed parathyroid-phase images show persistent parathyroid uptake with washout from thyroid. Adenoma appears as focal hot spot distinct from thyroid tissue.
Bone SPECT for Spine Lesions: What It Shows, Cost & Preparat
Focal areas of increased radiotracer uptake indicating increased osteoblastic activity. Lesions may appear as hot spots in vertebral bodies, pedicles, or posterior elements. SPECT provides 3D localization distinguishing anterior vs posterior elements, helping differentiate metastatic disease from benign conditions.
Thyroid SPECT (Hot/Cold Nodule): What It Shows, Cost & Prepa
Hot nodules show focal increased radiotracer uptake with suppression of surrounding thyroid tissue. Cold nodules demonstrate focal decreased or absent uptake within normally functioning thyroid parenchyma. Warm nodules show uptake similar to surrounding tissue. SPECT provides 3D localization and characterization of nodule functional status.
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