Radionuclide scan
A radionuclide scan, also known as a nuclear medicine scan, is a diagnostic imaging technique that employs radioactive tracers to visualize organs and tissues within the body. This scan primarily detects gamma rays emitted by the tracer, which is usually technetium-99m, allowing healthcare professionals to identify various medical conditions, particularly cancers such as thyroid, prostate, and neuroendocrine tumors. The procedure involves minimal patient preparation and is typically performed on an outpatient basis.
During the scan, a radiologist or nuclear medicine physician injects the radioactive material into a peripheral vein, and the patient lies down under a gamma camera that captures the emitted radiation. The imaging process takes about an hour, after which the results are analyzed and communicated to the patient for any necessary follow-up. Radionuclide scans are valuable tools for diagnosing not only cancers but also conditions like hypothyroidism, bone fractures, kidney issues, and even Alzheimer's disease.
While the procedure is generally safe, patients may experience minor discomfort at the injection site, and precautions are advised for pregnant individuals due to the exposure to radiation. Recent advancements in this field have enhanced the accuracy of cancer diagnosis and treatment, allowing for more tailored therapeutic approaches.
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Radionuclide scan
ALSO KNOWN AS: Nuclear medicine scan
DEFINITION: A radionuclide scan is the detection of electromagnetic radiation, usually gamma rays, emitted from an injected radioactive tracer that has been taken up by an organ in the body to be studied, to produce an image. The most common radioisotope used is technetium-99m, whose gamma rays are absorbed by a sodium iodide crystal detector. The radiation this detector absorbs generates an image that a radiologist or nuclear medicine physician interprets. The exceptions are positron emission tomography (PET) scanning, which uses positron emission; gallium scanning, which uses gallium as the radionuclide; and some thyroid imaging, which uses iodine.
Cancers diagnosed: Virtually all types of cancer, especially metastases; often used in thyroid cancer, prostate cancer, neuroendocrine tumors, liver cancer, lymphoma, and neuroblastoma
Why performed: A radionuclide scan is used to diagnose primary and secondary cancer (bone scan, iodine scan, PET scan) and to diagnose various ailments, including but not limited to the following: hypothyroidism or hyperthyroidism (thyroid scan), bone fractures and bone infection (bone scan), kidney obstruction (renal scan), inflammatory disorders such as sarcoid and fever of unknown origin (gallium scan), cardiomyopathy multiple uptake gated acquisition (MUGA scan), coronary artery disease (cardiac single photon emission computed tomography, or SPECT) pulmonary embolus (lung scan), and Alzheimer’s disease (brain SPECT). Radionuclide scans are commonly used to diagnose thyroid cancer, prostate cancer, neuroendocrine tumors, liver cancer, lymphoma, and neuroblastoma.
Patient preparation: The preparation for a radionuclide scan is minimal to none; the scan is usually performed as an outpatient procedure. For some procedures, the patient may be asked to fast several hours before the scan.
Steps of the procedure: The radioisotope is prepared by the technologist and injected into a peripheral vein by the radiologist or nuclear medicine physician. The patient is then placed supine on a table under a gamma camera that houses the detectors. The scan time is usually about one hour.
After the procedure: The scan is generated by the computer attached to the camera and read by the radiologist the same day. The patient must contact their doctor for the radiologist’s report and any follow-up therapy.
In the twenty-first century, advances have been made in radionuclide scans that have allowed for the better diagnosis and treatment of certain cancers. Specialized cameras used in nuclear imaging tests can reveal even the most minor tumors and help categorize the tumor type and stage. Theranostic radionuclides were developed for imaging and therapy, allowing for more precise diagnostics and treatment programs. Targeted radionuclides allow for individualized treatment plans. Finally, radionuclide scans allowed for the development of radiopharmaceutical therapy, which delivers cancer medications containing radiation directly to cancer cells.
Risks: The risks of this type of scan include minor pain or bruising at the injection site. If the patient is pregnant, the scan should be avoided if possible since the radiation dose, although small in most cases, is not negligible. Radioactive iodine should not be administered to a pregnant patient because of the risk to the fetus.
Results: The scan results are dependent on the type of scan performed and the reason for the study.
Bibliography
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