a technique to demonstrate abnormal metabolic activity in bone; involves intravenous injection of the radionuclide (usually sodium pertechnetate [technetium Tc99m methylene diphosphonate]) that shows in areas of active growth in bone making it possible to differentiate normal growth and excessive growth from the level of radioactivity emitted
This method can detect metastatic tumor to bone from the prostate, breast, lung, kidney, bladder and thyroid, arthritis, osteomyelitis, and new fractures. Other methods are WBC scan and gallium scan.
a technique to demonstrate the pattern of blood perfusion of the brain
The procedure involves intravenous injection of the radionuclide such as technetium 99m pertechnetate, mercury-210, or radioiodinated albumin. This method can diagnose cerebral hemorrhage, cerebrovascular accidents (CVA), tumor, hematoma, AV malformations, and aneurysms.
tests in which radioactive molecules are injected intravenously to demonstrate damages and evaluate the function of the heart
As the injected radionuclide circulates to the heart, the presence of radioactivity in the ventricles of the heart or the myocardium is measured.
Thallium scan: Thallium is taken up by normal cells, in which case the scan shows an evenly distributed pattern of radioactivity. Ischemic areas or infarcted areas take up less thallium and appear as cold spots on the scan.
method of creating cross-sectional images of the human body through the use of x-ray images compiled together into computer graphics; an x-ray study of the body in which radiographic images of cross-sections of the body is obtained
CT scan of the brain may reveal tumor, infarction, hydrocephalus, cortical atrophy, cerebral aneurysm, hematoma, A-V malformation. Study of the chest may reveal tumor, lymph nodes, cysts, abscess, effusion, and aortic aneurysm. Study of the abdomen may reveal tumor, hematoma, cysts. In some studies the image can be improved by contrast dye. The major complication is allergy to the dye in some patients.
a nuclear scan involving the intravenous injection of radioactive gallium
Gallium concentrates in areas of inflammation and tumor growth. Although liver, spleen, bone and colon retain gallium, it is possible to differentiate abnormal gallium uptake from normal retention. This is a useful test for the detection of metastatic tumor activity.
For patients who cannot exercise, the persantine-thallium scan can be used to reveal ischemic areas. Persantine is the trademark for the drug dipyridamole which is a coronary vasodilator. Persantine dilates normal coronary vessels more than the occluded vessels. Blood would preferentially flow to the normal vessels; a sort of "steal" phenomenon. A thallium scan can then reveal the ischemic areas by demonstrating reduced perfusion.
In the case of study on the myocardium, it can accurately distinguish between dyskinetic myocardium due to ischemia and due to infarction. In the case of study on the brain, it measures cerebral blood flow and cerebral oxygen and glucose metabolism. Cerebral metabolic rate is much lower in permanently unconscious patients.
Technetium scanning is a method of nuclear imaging based on the physiologic principles of increased blood flow, increased capillary permeability and active recruitment of white blood cells in an inflammatory reaction. Technetium Tc99m in blood is used to demonstrate areas of increased perfusion. In WBC scans, Tc99m labeled WBC demonstrates areas of infection.
Tc99m pyrophosphate scintigraphy: uptake in areas of recent myocardial infarction.
Tc99m labeled red cell scan: to localize site of a gastrointestinal bleed.
Tc99m using iminodiacetic acid compounds to demonstrate gallstones and obstructed cystic duct.
Tc99m phosphates to demonstrate metastatic cancer.
