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Nuclear Medicine
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Nuclear Medicine is a branch of medical imaging that uses the nuclear properties of matter in diagnosis and therapy.
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Nuclear Medicine uses radionuclides / radioisotopes or radiopharmaceuticals that are either injected into the vein or intradermally, ingested with food or liquids or inhaled in gaseous form.
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Nuclear Medicine exploits the way the body handles substances differently when there is disease or pathology involved.
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Nuclear Medicine shows physiological function as opposed to anatomy.
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The radionuclide introduced into the body is chemically bound to a complex that acts characteristically within the body. That complex is known as a tracer or ligand.
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Most diagnostic radionuclides emit gamma rays, while the cell damaging properties of beta particles are used in the therapeutic applications.
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It must be noted that the radiation delivered, presents a very small risk of inducing cancer. In fact, more radiation is absorbed by the body during a single short (1-2 hour) airplane flight than is taken by the majority of nuclear medicine studies.
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Any increased physiological function, such as a fracture in the bone, will show as increased concentration of the tracer; termed a “hot spot”.
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Some disease processes result in non-uptake of the tracer; called “cold spot”.
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Vein viewer on site for venous canulation
Common Terminology
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Planar - Provides a two-dimensional view of the process of function of the organ being imaged.(Also known as static images)
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SPECT - (Single Photon Emission Computed Tomography) provides 3-D computer-reconstructed images measuring and determining the function or physiology in a specific organ, tumor, or other metabolically active site.
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Tomography - From the Greek words "to cut or section" (tomos) and "to write" (graphein). A method of separating interference from the area of interest by imaging a cut section of the object.
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Nuclear Medicine Scan - The images produced as the result of a nuclear medicine procedure, often referred to as the actual procedure, examination or test.
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Radiopharmaceutical - Also referred to as tracer or radiounclide. The basic radioactively tagged compound necessary to produce a nuclear medicine image.
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Gamma Camera - The basic instrument used to produce a nuclear medicine image.
Single-photon emission computer tomography (SPECT)
SPECT is a scintigraphic technique in which a computer-generated image of local radioactive tracer distribution in tissues is produced through the detection of single-photon emissions from radionuclides introduced into the body that is able to provide true three-dimensional (3D) information. This information is typically presented as cross-sectional slices through the patient but can be freely reformatted or manipulated as required.
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SPECT camera may be combined with computerised tomography (CT) unit to form a hybrid system and fusion imaging of the physiology and anatomy of the area/s being scanned. Combined SPECT/CT devices provide both the functional information from SPECT and the anatomic information from CT in a single examination. SPECT/CT acquisitions can include the whole body, a limited portion of the body, or an organ. (Mariani et al., 2008).
Gamma Probe
The gamma probe is a handheld device that is used to localise abnormalities that are taken up by Technetium 99m, F-18 and Iodine based pharmaceuticals. The probe is used before and during surgery for accurate localisation, following the administration of the above-mentioned tracers.
It is commonly used for sentinel lymph node localisation and parathyroid adenoma localisation.
Fast Facts About Nuclear Medicine
Nuclear medicine procedures are unique, safe and cost-effective
There are nearly 100 different nuclear medicine imaging procedures available today
Nuclear medicine uniquely provides information about both the function and structure of virtually every major organ system within the body
Nuclear medicine procedures are among the safest diagnostic imaging tests available
The amount of radiation in a nuclear medicine procedure is comparable to that received during a diagnostic X-ray
Nuclear medicine procedures do not require anesthesia
Children commonly undergo nuclear medicine procedures to evaluate bone pain, injuries, infection, or kidney and bladder function
Common nuclear medicine applications include diagnosis and treatment of hyperthyroidism (Grave's Disease), cardiac stress tests to analyze heart function, bone scans for orthopaedic injuries, lung scans for blood clots, and liver and gall bladder procedures to diagnose abnormal function or blockages
GI Bleed Study
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​​Purpose
This study is performed to localise the site of gastrointestinal bleeding (GI Bleed), in a patient who is actively bleeding. The bleeding can occur within the upper or lower GI tract. Sites of active bleeding are identified by the accumulation and movement of radiolabeled red blood cells within the bowel lumen.
Iodine Whole Body Scan
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Purpose
It can reveal what one cannot see using traditional X-ray technology. This scan is performed on patients who have had an operation to remove cancer of the thyroid. It identifies how much thyroid tissue is left. By scanning the full length of the body it can be determined if the cancer has spread to other parts of the body.
Tektrotyd Scan (Octreotide)
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​​Purpose
The Tektrotyd scan is used to detect the existence of carcinoid tumours. These tumours interact with a hormone called somatostatin. The pharmaceutical tektrotyd, used for the scan in combination with a radioactive material (Technetium 99m), is chemically similar to this hormone. Whole-body imaging allows for detection of the primary tumour as well as metastases. SPECT imaging assists in tumour localization
Parathyroid Scan
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Purpose
The parathyroid glands, located above and below the thyroid gland of the neck, but separate from the thyroid in function, control calcium metabolism in the body. The parathyroid glands produce parathyroid hormone (PTH). PTH regulates the level of calcium in the blood. If too much PTH is secreted, the bones release calcium into the bloodstream. Over time, the bones become brittle and more likely to break. A parathyroid scan is acquired when the parathyroid appears to be overactive and a tumor is suspected. The gamma probe is used to localise the adenoma in theatre if it is seen on the parathyroid scan.
Sentinel Node Imaging
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Purpose
This is used to identify the first lymph node that the tumour drains into after administration of the radiotracer. This is used in patients with a lump in the breast or patients with melanoma. Once the sentinel node is localised using nuclear medicine imaging, the patient will go to the theatre to remove those nodes. The gamma probe is then used in theatre to aid the surgeon in locating the sentinel lymph node.
Cardiac MIBI Study
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Purpose
This study assesses the blood flow to the heart muscle as well as the amount of normal heart muscle the patient has. The indications for this study are to identify ischemic or infarcted cardiac tissue from normal cardiac tissue.
This examination may take the whole day.
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Appointments
All appointments are made through the cardiologist.
Bone Scan
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Purpose
A specialized scanner reveals the small amounts of infused radioactive material that move through the bloodstream and collect in the bones, especially in abnormal areas.
Bone scans are used for the detection and monitoring of bone disorders, including Paget's disease, cancer, infections, and fractures. Bone scanning is also useful in assessing joint diseases.
Muga Scan
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Purpose
To assess the difference when the heart is full and when it has pumped out blood it assesses the Left Ventricular Ejection Fraction (LVEF).
The MUGA scan (Multiple Gated Acquisition Scan) is an extremely useful noninvasive tool for evaluating the function of the heart. The MUGA scan produces a moving image of the beating heart, which allows one to identify any abnormalities with the heart’s pumping mechanism.