Clinical radionuclide bone imaging
Article Abstract:
Radionuclide bone imaging (RNBI) is a diagnostic technique whereby radioactive materials are administered, which then become temporarily incorporated into the bones. The radiation given off by these tracers is then detected by sensitive equipment to produce images of the bones. Radiolabeled phosphate esters are the usual materials administered, because they deposit mainly in the bones. High deposition rates in other tissues can reveal problems. RNBI is the main diagnostic procedure used to detect bone cancer. It discovers lesions not found by normal X-rays. RNBI should be used with other imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MR) prior to biopsy. Its use may also be indicated when other cancers are diagnosed and bone cancer is highly associated with the diagnosed cancer. A number of characteristics are seen on an RNBI image that can indicate malignant bone cancer. One of these is the presence of multiple randomly distributed foci of intense abnormal tracer accumulation. Single sites of accumulation may also indicate disease. Extraordinary bone-to-soft tissue activity on an image (super scan) and increased tracer accumulation because of new bone growth (flare) also indicate bone cancer. RNBI is also used to image fractures when they are suspected but not found by normal X-rays. The causes of osteonecrosis (death of bone tissue often from lack of blood supply) can often be found using RNBI. RNBI is also very useful in diagnosing problems associated with hip implants and other implants that replace natural bone structures. RNBI can also be used to detect osteomyelitis (inflammation of the bone marrow) and osteoarthritis (noninflammatory arthritis). It also be used when patients have pain in bone structures and the cause is unknown, as well as in diagnosing the little understood problem of reflex sympathetic dystrophy. RNBI is a valuable diagnostic tool and the practitioner should be aware of its strengths and limitations. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Radiology
Subject: Health
ISSN: 0033-8419
Year: 1990
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Upper gastrointestinal tract evaluation with radionuclides in infants
Article Abstract:
Gastroesophageal reflux (GRE, regurgitation of stomach contents) is often seen in infants. It is implicated in a number of other diseases affecting infants, including asthma, failure to thrive, and sudden infant death syndrome (SIDS). Examination of gastric (stomach) emptying is used to detect GRE and its underlying causes. This often involves the use of radionuclides (radioactive material) to produce images of the upper gastrointestinal tract. The patient is fed a meal containing the radionuclide and then scanned for 90 minutes to measure gastric emptying rate. The lower limits for normal gastric emptying have been standardized as being 45 percent by 60 minutes and 60 percent by 90 minutes. Images are continually obtained during the 90 minutes. These images are enhanced by a computer and examined for any signs of reflux. The episodes of reflux are characterized and staged. This careful review of the images helps diagnose, characterize and find the underlying causes of delayed gastric emptying. Aspiration (taking into the lungs) of gastric contents is also studied after gastric emptying has been completed. The important question is whether delayed gastric emptying is an indicator of GRE. No definitive studies have been performed to show this, but it is likely that such a relationship exists. An article in the February 1991 issue of Radiology contends that gastric emptying test results may be highly variable, depending upon time examined, such that an abnormal result in a one-hour test might be normal in a two-hour test. The continuous and close evaluation of the emptying process yields important information beyond just the mere percentage of emptying at two time periods. Such data can be very useful in detecting GRE. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Radiology
Subject: Health
ISSN: 0033-8419
Year: 1991
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