Nuclear Medicine 

What is a Nuclear Medicine Scan and what it is used to diagnose?

Nuclear medicine uses small amounts of radioactive material combined with a carrier molecule. This compound is called a radiotracer or radiopharmaceutical. Doctors use nuclear medicine tests to diagnose, evaluate, and treat various diseases. These include cancer, heart disease, gastrointestinal, endocrine, or neurological disorders.

Nuclear medicine determines how the body is functioning at a cellular level. It is able to:
  • find disease in its earliest stages
  • target treatment to specific cells
  • monitor response to treatment

These tests help diagnose and assess medical conditions. They are non-invasive and usually painless.


When a radiotracer is injected into the body, it builds up in certain areas of the body. Radiotracers go to the area of the body that need to be examined, such as a cancerous tumor or an inflamed area. They can also bind to certain proteins in the body.


Doctors use nuclear medicine imaging procedures to see what’s happening at a cellular level and to better understand how the body is functioning.


In adults, doctors use nuclear medicine to:



  • look at blood flow and function (such as a myocardial perfusion scan)
  • detect coronary artery disease and the extent of coronary stenosis
  • assess damage to the heart following a heart attack
  • evaluate treatment options such as bypass heart surgery and angioplasty
  • evaluate the results of revascularization procedures
  • check for heart transplant rejection
  • check heart function before and after chemotherapy (MUGA)



  • check for breathing and blood flow problems
  • assess lung function for surgery
  • check for lung transplant rejection



  • check bones for fractures, infection, and arthritis
  • evaluate metastatic bone disease, prosthetic joints, and bone tumors
  • look for biopsy sites



  • investigate abnormalities in patients with seizures, memory loss and blood flow problems
  • detect the early onset of neurological disorders such as Alzheimer's disease
  • assist in surgical planning and radiation planning
  • identify areas of the brain that may be causing seizures
  • evaluate abnormalities in patients with suspected Parkinson's disease or other movement disorders
  • check for a recurring brain tumor
  • look for biopsy sites


Other Body Systems

  • look for inflammation or abnormal function of the gallbladder
  • look for bleeding into the bowel
  • assess complications following gallbladder surgery
  • evaluate swelling caused by the backup of lymph fluid (lymphedema)
  • find the cause of unexplained fever
  • find infection
  • measure thyroid function
  • help diagnose blood cell disorders
  • evaluate how the stomach empties
  • evaluate the flow of spinal fluid and look for leaks.


Doctors also use nuclear medicine to:



  • determine the stage of cancer
  • look to see if cancer has spread
  • find the lymph node closest to a tumor (sentinel)
  • plan treatment
  • evaluate how the cancer is responding to therapy
  • check for recurring cancer
  • detect rare tumors of the pancreas and adrenal glands



  • analyze kidney blood flow and function
  • detect a blockage in the urinary tract
  • evaluate for high blood pressure (hypertension) in the kidney arteries
  • look for a kidney infection
  • evaluate the abnormal flow of urine (reflux)

What to Expect

Before arriving

Tell your doctor, the scheduler and the technologist if you're pregnant or might be pregnant.


Women should always tell their doctor and technologist if they are pregnant or breastfeeding. 


Tell the scheduler, doctor and technologist about any medications you are taking, including vitamins and herbal supplements. List any allergies, recent illnesses, and other medical conditions.


Leave jewelry and accessories at home or remove them prior to the exam. These objects may interfere with the procedure.


Your doctor or the scheduler will tell you how to prepare for your specific exam.


During the test

You may wear a gown, or the technologist may allow you to wear your own clothing during the exam.


Nuclear medicine scans may be performed on many organs and tissues of the body. Each type of scan employs certain technology, radionuclides, and procedures.


A nuclear medicine scan consists of 3 phases: tracer (radionuclide) administration, taking images, and image interpretation. The amount of time between administration of the tracer and the taking of the images may range from a few moments to a few days. The time depends on the body tissue being examined and the tracer being used. Some scans are completed in minutes, while others may need the patient to return a few times over the course of several days.


One of the most commonly performed nuclear medicine exams is a heart scan.


What does the equipment look like?


Gamma Camera

The gamma camera detects the energy from the radiotracer in your body and converts it into an image. The gamma camera itself does not emit any radiation. It has radiation detectors called gamma camera heads. These are often shaped like a box and attached to a round, donut-shaped gantry. The patient lies on an exam table that slides in between two gamma camera heads that are above and below the patient. Sometimes, the doctor will place the gamma camera heads at a 90-degree angle over the patient's body.


In SPECT, the camera heads rotate around the patient's body to produce highly detailed, 3D images.

You will lie on an exam table. A nurse or technologist will insert an intravenous (IV) catheter into a vein in your hand or arm.

You will receive an injection of the radiotracer. Or you may swallow it or inhale it as a gas.

The radiotracer will travel through your body and build up in the area of your body being studied. This may take anywhere from several seconds to several days. Your doctor will tell you when imaging will begin and how long the procedure will last.

When imaging begins, the camera or scanner will take a series of images. The camera may rotate around you or stay in one position. You may need to change positions during the test. You will need to remain still for brief periods. In some cases, the camera may move very close to your body. This is necessary to get the best quality images. Tell the technologist if you have a fear of closed spaces.

The length of time for nuclear medicine test varies. The actual imaging time ranges from 20 minutes to several hours. Your test may be done over a period of several days.


After the exam, you may need to wait to make sure no more images are needed.

If you have an intravenous (IV) line for the procedure, your technologist will remove it. If you have another procedure scheduled for the same day, your IV will be left it in place.

What will I experience during and after the procedure?

Except for intravenous injections, most nuclear medicine procedures are painless. Significant discomfort and side effects are rare.

You will feel a slight pin prick when the technologist inserts the needle into your vein for the intravenous line. You may feel a cold sensation moving up your arm during the radiotracer injection. Generally, there are no other side effects.

Radiotracers have little or no taste. Inhaling a radiotracer feels no different than breathing the air around you.

It is important to remain still during the exam. Nuclear imaging causes no pain. However, having to remain still or in one position for long periods may cause discomfort.

Unless your doctor tells you otherwise, you may resume your normal activities after your exam.

A technologist, nurse, or doctor will provide you with any necessary special instructions before you leave.

The small amount of radiotracer in your body will lose its radioactivity over time through the natural process of radioactive decay. Much of it will pass out of your body through your urine or stool the first few hours and days after your test. Drink plenty of water to help flush the radiotracer out of your body. You will need to follow safety precautions to keep from exposing other people to radiation. 


  • Nuclear medicine exams use only a small dose of radiotracer acceptable for diagnostic exams. The potential benefits of an exam outweigh the very low radiation risk.
  • Doctors have been using nuclear medicine diagnostic procedures for more than six decades. There are no known long-term adverse effects from such low-dose exposure.
  • Your doctor always weighs the benefits of nuclear medicine treatment against any risks. Your doctor will discuss the significant risks prior to treatment and give you an opportunity to ask questions.
  • Allergic reactions to radiotracers are extremely rare and usually mild. Always tell the nuclear medicine personnel about any allergies you may have. Describe any problems you may have had during previous nuclear medicine exams.
  • The radiotracer injection may cause slight pain and redness. This should rapidly resolve.
  • Women should always tell their doctor and radiology technologist if there is any possibility that they are pregnant, or they are breastfeeding. 


Brighton’s board-certified radiologist studies your Nuclear Medicine exam and provides the results to your doctor.