Common nuclear medicine scans include:
- Bone Scans
- Gastrointestinal bleeding scans
- Liver spleen scans
- Thyroid scans
- Renal scans
- Gallium scans
- Ventilation-perfusion scans
- White blood cell scan
Bone scintigraphy is a diagnostic study used to evaluate the distribution of active bone formation in the body. Bone scans are used for evaluation of multiple conditions including checking for spread of tumor to the bones (metastases), occult fractures, infection of the bones (osteomyelitis), stress fracture, arthritis, bone pain, evaluation of orthopedic hardware and possible associated complications. Whole body imaging, limited bone scintigraphy or bone SPECT imaging may be performed depending on the indication.
- Whole-body bone scintigraphy produces images of the skeleton, including front and back views of the skeleton. Additional views are obtained as needed.
- Limited bone scintigraphy records images of only a portion of the skeleton.
- Bone single-photon emission computed tomography (SPECT) produces a three dimensional image (tomographic image) of a portion of the skeleton. This image can be fused with a concurrently obtained localization computerized tomogrphy (CT image) with SPECT-CT camera to produce a SPECT-CT image and helps in localization of the abnormal radioactivity.
- Multiphase bone scintigraphy usually includes blood flow images, immediate images, and delayed images limited to an area of interest. The blood flow images are a dynamic sequence of images of the area of greatest interest obtained as the tracer is injected. The immediate (blood pool or soft tissue phase) images include 1 or more static images of the areas of interest, obtained immediately after the flow portion of the study and completed within 30 minutes after injection of the tracer. Delayed images may be limited to the areas of interest or may include the whole body, may be planar or tomographic, and are usually acquired 2–5 h after injection. If necessary, additional delayed images may be obtained up to 24 hours after tracer injection.
Gastrointestinal bleeding scans
Gastrointestinal bleeding scans are used for localization of the source of bleeding in the small or large bowel. Gastrointestinal bleeding scintigraphy is performed in patients suspected of active gastrointestinal bleeding using radioactivity labeled red blood cells (RBCs). Sites of active bleeding are identified by the accumulation and movement of red blood cells labeled with radioactivity within the bowel lumen. Since activity within the lumen of the bowel can move, frequent images as fast as1 image every 60 seconds increases the accuracy of localizing the bleeding site.
Hemangioma studies are obtained for detection of vascular tumors called hemangioma in the liver and also used red blood cells tagged with radioactivity to localize these tumors. These scans help in localization of hepatic hemangiomas or correlation and confirmation possible hemangioma found on ultrasound or CT scan or other imaging studies.
- Gastric emptying studies are used in evaluating incomplete or delayed gastric emptying. These studies help to quantify gastric emptying rate of food, solid or liquid. Radionuclide studies of gastric emptying and motility are the most natural ways to study gastric motor function. The study is noninvasive, uses a physiologic meal (solids with/without liquids), and is quantitative. With our protocol, we can measure how long it takes for the meal to move through the stomach. Serial testing can determine the effectiveness of therapy.
Gatroesophageal reflux studies
Gatroesophageal reflux studies are used to study the presence of reflux of stomach contents into the esophagus. It uses a small amount of radioactive material that helps in assessing if stomach contents reflux back into the esophagus instead of proceeding in the small bowel.
Liver spleen scans
Liver spleen scans help in evaluation of function of the liver and/ or spleen. They are used to add functional information not available with the usual anatomic imaging methods of Compuerized Tomography (CT), Ultrasound (US), and Magnetic Resonance Imaging (MRI). They help in assessment of anatomy, size, and relative position of the liver and spleen, in assessment of benign focal conditions or chronic liver or spleen diseases jaundice, cirrhosis, hepatocellular disease, hepatitis, hepatic abscess, or elevated laboratory results.
HIDA scans are used in diagnosis of various acute and chronic liver and gallbladder (hepatobiliary) diseases like cholecystitis, obstruction of the common bile duct, altered motor function or contraction of the gall bladder. The test helps assess the flow of bile to assess gall bladder function and bile flow.
Thyroid Scintigraphy is a procedure used for evaluation of thyroid dysfunction, either hyperthyroidism or hypothyroidism. These scans help in detection, evaluation and localization of lump or nodules within the thyroid gland and differentiation of hot versus cold nodules. The differentiation helps in selection of nodules for biopsy. The radioactive substance administered will travel through the bloodstream to the thyroid gland. The thyroid gland that is functioning shows up on a scan. Nodules absorbing more radioactive substance than the surrounding thyroid tissue are considered to be “hot,” and are typically non-cancerous. Nodules absorbing too little substance are considered “cold,” and are more likely to be cancer although most will still be benign. A special probe is used to evaluate thyroid function with radioactive iodine uptake (RAIU) measurement.
Parathyroid scans are typically indicated for localization of suspected overactive parathyroid glands (hyperparathyroidism). Hyperparathyroidism refers to elevation of parathyroid hormone. The causes may be primary (due to benign tumors in one or more of the four parathyroid glands) or secondary (altered metabolism causing enlargement in generally more than one parathyroid gland). Detection and localization of adenomas/ hyperplasia in primary and secondary hyperparathyroidism helps the surgeons to perform a noninvasive surgery if indicated.
Ventricular shunt, Cisternography
Ventricular shunt, Cisternography helps in evaluation of circulation of cerebrospinal fluid in the spinal cord and ventricles in the brain. The scan is performed by injecting a small amount of radioactive material in the in the spinal column and then study flow, obstruction or leakage.
Renal scans are performed for evaluation of kidney function and flow of urine in the urinary tract. These scans are often done with lasix to assess obstruction in the urinary tract and are often indicated in hydronephrosis. They may also be indicated to assess renal blood flow isuch as within renal transplants and in conditions of reduced kidney function or hypertension.
Gallium 67 was developed initially as a bone-seeking radiopharmaceutical, found use as a tumor-imaging agent, and later was found to have infection-seeking properties. In the 1970s, Ga-67 scans was the mainstay for imaging of infection. Although it is not used as much today, Ga-67 still has important utility in selected clinical settings like evaluation of chronic inflammation (abscesses), evaluation of pulmonary disorders (sarcoidosis), detection and localization of infections like bone infections (osteomyelitis) or even evaluation of fever of unknown origin.
These studies are typically indicated in patients with melanoma or breast cancer. It is used to study the drainage of small amount of material injected around the area of interest and is used identify the first lymph node or nodes that drain the area (sentinel node). These nodes help the surgeon harvest the best selected nodes to study the spread of the primary tumors.
Lymphoscintigraphy is also a safe, minimally invasive, repeatable method of assessing for swelling of lower limbs in clinically suspected lymphedema. Lymphedema is a chronic debilitating disease that results from an accumulation of lymphatic fluid that causes swelling in the arms and legs. Damage, blockage or defect of the lymphatic system can cause a disruption in the lymphatic fluid flow.
Ventilation and Perfusion scans
The study uses radioactive tracer to assess lung ventilation (air flow) and perfusion (blood flow). The lung ventilation study demonstrates the distribution of ventilation, air space, and air trapping within the lungs. The lung perfusion study demonstrates the distribution of lung perfusion via the pulmonary arteries in multiple projections. The two in conjunction are used for diagnosis of blood clot to the lungs (pulmonary embolism).
The lung quantitative scan helps in evaluation of general and regional lung perfusion prior to lung reduction surgery or to monitor post surgical changes.
Nuclear dacroscintigraphy is used for assessment of blockage of normal pathway of drainage of tears from the eyes into the nose and resultant increased tearing (epiphora).It is used for determination of site of blockage in the pathway which may be the cause of blockage. It is simple and a safe and more physiological method of assessment compared to conventional radiography.
White blood cell scan
White blood cell scans uses a small amount of the patients white blood cells labeled with radioactive material to identify sources of infection, fever.
Therapeutic nuclear medicine procedures using radioactive material to treat conditions affecting thyroid gland including the thyroid cancer.
- Radioiodine therapies for thyroid cancer and hyperthyroidism
- Quadramet, Samarium, Alpha radin therapy(Xofigo) for bone metastases
- Zevalin therapies for lymphoma