What is General Nuclear Medicine?


Nuclear Medicine is a subspecialty within the department of radiology similar to X-ray, Ultrasound, CT or MRI. General nuclear medicine utilizes a small amount of radioactive materials to diagnose or treat a variety of abnormalities to the body as well as diseases. A specific radiopharmaceutical, called radiotracer, is designed to go to specific organ systems. Radioactive tracers are not the same as contrast agents and do not contain iodine. Thyroid radioactive tracers are iodine based but reactions from this small amount is extremely rare. Depending on what type of nuclear medicine exam you are undergoing, the radioactive tracer is either inhaled as a gas, injected into the vein or ingested with food or drink. Once in the body the radioactive tracer gives off energy in the form of gamma rays. This energy is detected by equipment called a gamma camera or an uptake probe. This specialized equipment works in conjunction with a computer to measure the amount of radiotracer absorbed in your body as well as detect how things are functioning.


Nuclear medicine also offers therapeutic examinations for the treatment of medical conditions affecting the thyroid gland or treating thyroid cancer.


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How does Nuclear Medicine work?


In X-ray and CT the radiation given to a patient comes from the equipment to create an image. This phenomenon is the complete opposite for nuclear medicine with the radiation coming off of the patient and equipment creating the images. This is how nuclear medicine can see the functionality of the body over the course of time. Areas of greater intensity seen on the images represent larger amounts of radioactive tracer accumulation. Less intense areas seen on nuclear medicine images indicate smaller concentrations of radioactive tracer. These differences in intensity can represent the body's differences in the rate of metabolism or chemical activity.


In radioactive iodine therapy, a capsule or liquid form of I-131 is swallowed, absorbed into the bloodstream in the gastrointestinal tract and gathered in the thyroid gland where it destroys abnormal cells.


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Common Nuclear Medicine Exams:

  • Bone Scan
  • 3-Phase Bone Scan
  • Indium White Blood Cell Exam
  • GI Bleed Scan
  • MUGA Scan
  • Rest / Stress Cardiac Exam
  • Renal Scan
  • Liver / Spleen Scan
  • Gastric Emptying Exam
  • Thyroid Uptake and Scan
  • Parathyroid Exam
  • VQ Lung Scan
  • HIDA Gallbladder Exam
  • Lymphatic or Sentinel Node Exam
  • Meckel's Scan
  • Shunt Study
  • Brain Scan
  • Tumor Imaging

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Common uses of Nuclear Medicine Exams:


  • evaluates kidney function
  • visualizes heart blood flow and function
  • reviews the lungs for respiratory and blood flow abnormalities
  • identifies gallbladder abnormalities
  • recognizes bones with fractures, infections, arthritis and tumors
  • determines the presence or spread of cancer in various parts of the body
  • discovers bleeding in the bowels
  • locates the presence of infection
  • measures the thyroid glands function
  • investigates abnormalities to the brain
  • localizes the lymph nodes before surgery


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What Should I expect?


The amount of time needed for a nuclear medicine exam varies greatly depending on the type of exam. The actual scanning time for nuclear medicine exams can take from 20 minutes to several hours and may be conducted over several days.


An IV may be placed in a vein in your arm or hand, depending on the exam requested. Please notify the technologist if you have another exam scheduled the same day as your nuclear medicine exam. This sometimes can help reduce the number of IV sticks to the patient.


When obtaining images using a gamma camera, the patient may be instructed to be positioned a certain way. It is important that you remain motionless while the images are being recorded. The camera may rotate around you or may stay in one position to acquire images. The camera may move close to your body and is necessary to obtain the best quality images. If you are claustrophobic, please inform the ordering physician and technologist prior to imaging.


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Patient preparation


The type of nuclear medicine exam ordered will determine what kind of preparation is needed. Some nuclear medicine exams will require the patient to withhold medications, not eat or drink for a certain period of time or may require a bowel prep the evening before.


What are the risks?


  • The radiotracer administered to the patient is small and will result in low radiation exposure. Thus, the radiation risk is very low compared to the potential benefits.

  • Allergic reactions to radiopharmaceuticals may occur but are extremely rare and usually mild. You should inform the nuclear medicine technologist if you think you may be having a reaction.

  • Injections of the radioactive tracer may cause slight pain and should rapidly resolve.

  • Women should inform the technologist and ordering physician if there is a possibility they are pregnant or breast feeding.

After your exam


When the examination is completed, you may be asked to wait until the technologist checks the images. Occasionally, additional images are needed to help verify structures better. The additional images do not necessarily mean there is a problem with your exam or you have an abnormality. You will not be exposed to any additional radiation during this process.


The small amount of radiotracer in your body will lose its radioactivity over time. It may also pass out of your body through your urine and stool during the first few hours or days following the test. You may be instructed to take special precautions such as flushing the toilet twice and washing your hands more frequently. You should drink plenty of water to help flush the radioactive materials out of your body.