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Major Advances in Nuclear Medicine Diagnosis and Treatment

Exploratory surgery used to be the way doctors investigated health problems. Doctors would cut, poke, and prod. But since the 1940's, nuclear technologies have offered an increasing array of diagnostic techniques that help patients avoid the pain of surgery while their physicians gain knowledge of the body's inner workings.

X-rays, MRI scanners, CAT scans, and ultrasound each use nuclear science and technology to troubleshoot different parts of the body and diagnose conditions. Each of these are non-invasive procedures which means patients do not need to undergo any kind of surgery. More advanced nuclear medicine uses computers, detectors, and radioactive substances, called isotopes, to give doctors even more information about a patient's internal workings. Known as nuclear imaging, these procedures include bone scanning, Positron emission tomography (PET), Single photon emission computed tomography (SPECT) and Cardiovascular imaging. The use of these procedures depends on the patient's symptoms.

One out of three patients admitted to hospitals undergo at least one medical procedure that uses isotopes. Isotopes are substances with identical chemical properties that sit on the same place on the Periodic Chart of Elements, but they have different atomic weights. Both radioactive isotopes (also called radioisotopes) and stable isotopes contribute to techniques to improve a physician's ability to diagnose ailments.

Radioisotopes are useful because the radiation they emit can be located in the body. They can be administered by injection, inhalation, or orally. A gamma camera captures an image from isotopes in the body that emit gamma radiation. Then, computers enhance the image, allowing physicians to detect tumors or fractures, measure blood flow, or determine thyroid and pulmonary functions.

Clinical trials across the United States have demonstrated the success of using nuclear medicine to treat illness as well as diagnosis it. For example, the University of Washington has investigated a technique called cell targeted therapy that has been used to treat leukemia and b-cell lymphoma. The technique involves the injection of radio-labeled peptides, proteins, and monoclonal antibodies to deliver the radioactivity directly and selectively to cancer cell surfaces. Like "smart bullets," the radioisotopes irradiate and kill the cancer in its place.

In the case of leukemia, cell targeted therapy is used in conjunction with other treatments such as bone marrow transplant. For patients who have received this therapy, the remission rates are above 80 per cent. The curative power of cell targeted therapy is high, compared to chemo therapy which is successful less than 50% of the time depending on the type, stage, and site of the cancer. In fact, many cancer experts in Europe prefer cell-targeted therapy technology to avoid the highly toxic effects of other treatments.

A Texas woman with Hodgkins disease failed 13 rounds of chemo and whole body radiation and was given 6 months to live. She switched to cell targeted therapy and was injected with a protein labeled with yttriium-90, an element extracted and purified from Hanford wastes. She was treated as an outpatient. The costs were about 1/10 of the costs of traditional cancer therapy. These costs covered by her insurance and produced minimal side effects. While still considered a radical treatment option, cell targeted therapy helped this woman, a medical professional herself, halt the advancement of her disease and watch her sons mature.

With contributions from ANS member Michael R. Fox, Ph.D.

Last updated July 10, 2012, 10:27am CDT.

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