WHAT IS NUCLEAR MEDICINE?
Nuclear medicine is a branch of medical imaging that uses small amounts of radioactive material to diagnose a variety of diseases, including many types of cancers, and other abnormalities within the body.
Nuclear medicine, or radionuclide imaging procedures, are noninvasive and, with the exception of intravenous injections, are usually painless medical tests that help physicians diagnose a variety of medical conditions. These imaging scans use radioactive materials called radiopharmaceuticals or radiotracers.
Depending on the type of nuclear medicine exam your child is undergoing, the radiotracer is either injected into a vein, swallowed, or inhaled as a gas. Eventually it accumulates in the organ or area of the body being examined, where it gives off energy in the form of gamma rays. This energy is detected by a device called a gamma camera. This camera works with a computer to measure the amount of radiotracer absorbed by the body, and will produce special pictures offering details of both the structure and function of organs and tissues.
Unlike other imaging techniques, nuclear medicine imaging exams focus on depicting physiologic processes within the body, such as rates of metabolism or levels of chemical activity, instead of showing anatomy and structure. Areas of greater intensity, called "hot spots", indicate where large amounts of radiotracer have accumulated and where there is a high level of chemical activity. Less intense areas, or "cold spots", indicate a smaller concentration of radiotracer and less chemical activity.
WHY IS IT DONE?
Physicians use radionuclide imaging procedures to visualize the structure and function of organ tissue, bone, or systems of the body. Nuclear medicine imaging scans are performed to diagnose:
- urinary blockage in the kidney
- backflow of urine from the bladder into the kidney
- bone cancer, infections, and trauma
- gastrointestinal bleeding
- locate the presence of infection
- tumors and the spread of cancer throughout the body
HOW IS THIS PROCEDURE PERFORMED?
Nuclear medicine imaging is usually performed on an outpatient basis, but is often performed on hospitalized patients as well.
The type of nuclear medicine examination will determine how the radiotracer is introduced into your child's body:
- Intravenous: a small needle may be used to inject the radiotracer. The needle is removed immediately after. At times, an indwelling intravenous line may be needed for the duration of the exam.
- Oral: for some exams, the radiotracer is taken by mouth, such as for a gastroesophageal reflux test.
- Inhaled: occasionally the radiotracer will be inhaled as a gas via a mask, such as with a lung scan.
- Bladder: some exams require a catheter to be inserted into the bladder, such as with a vesicoureteral reflux study.
It can take anywhere from several seconds to several days for the radiotracer to travel through the body and accumulate in the organ or area being studied. As a result, imaging may be done immediately, a few hours later, or even a couple of days after the radioactive material is given. When it is time for the imaging to begin, your child will lie down on an examination table. The gamma camera will then take a series of images. The camera may rotate around your child, or the camera will stay in one position, and your child will be asked to change positions. While the camera is taking pictures, your child will need to remain still for brief periods of time.
Examinations that require longer imaging times may require sedation for your child. If your child’s exam is scheduled with sedation, fasting may be required. A nurse will contact you 1 to 2 days before the procedure to give you age specific instructions for preparing your child. Sedation medicines are usually given through an IV and will help your child to stay calm and still while the images are taken. A technician will start the IV and a nurse will administer the medicine. A nurse will also monitor your child during and after the procedure until the sedation has worn off. Watch a child-friendly video explanation of how an IV is placed.
WHAT TO EXPECT
Except for intravenous injections, most nuclear medicine procedures are painless and are rarely associated with significant discomfort or side effects. With some studies, a catheter may be placed into the bladder, which may cause temporary discomfort. Though nuclear imaging itself causes no pain, children may experience some discomfort from having to remain still during imaging. Parents are encouraged to stay with their children to help them remain calm and still during imaging. Comfort items such as pacifiers, blankets or favorite DVD are also very helpful. A television with children's programming is available in the scanning room.
If the radiotracer is given intravenously, your child will feel a pin prick, much like a shot, when the needle is inserted into the vein. When the radioactive material is injected into the arm, your child will usually not experience any discomfort. When swallowed, the radiotracer has little or no taste. If inhaled, your child should feel no differently than when breathing room air or holding his or her breath.
The length of time for nuclear medicine procedures varies greatly, depending on the type of exam. Actual scanning time for nuclear imaging exams can take from 20 minutes to several hours and may be conducted over a couple of days.
Unless your physician tells you otherwise, your child may resume his/her normal activities after the nuclear medicine scan.
If sedation was used, your child will stay with a nurse in a recovery area in until the affects of the sedation have worn off. Through the natural process of radioactive decay, the small amount of radiotracer in your child’s body will lose its radioactivity over time. In many cases, the radioactivity will dissipate over the first 24 hours following the test and pass out of your child's body through urine or stool. Your child should also drink plenty of water to help flush the radioactive material from his or her body.
PREPARATION FOR EXAM
Special instructions and preps for your child's exam
Additional information on Nuclear Cystogram Exam
Additional information on Lasix Renal Scan
You may reassure your child that you will be able to be in the room with her/him during the procedure. If your child is old enough, you may choose to explain the procedure yourself. Most pediatric nuclear medicine exams will involve an injection into a vein in your child's arm or hand.
Children should wear comfortable, loose-fitting clothing to the exam, but they may be given a gown to wear during the procedure.
You should inform your physician of any medications your child is taking as well as vitamins and herbal supplements and if he or she has any allergies. Also inform your doctor of any recent illnesses or other medical conditions.
Jewelry and other metallic accessories should be left at home if possible, or removed prior to the exam because they may interfere with the procedure.
You will receive a phone call prior to your child’s procedure with specific preparation instructions for what your child may eat and drink before the exam, especially if your physician plans to use sedation to help calm your child.
WHAT ARE THE BENEFITS vs. RISKS?
- The information provided by nuclear medicine examinations is unique and often unattainable using other imaging procedures.
- For many diseases, nuclear medicine scans yield the most useful information needed to make a diagnosis or to determine appropriate treatment, if any.
- Because the doses of radiotracer administered are small, diagnostic nuclear medicine procedures result in low radiation exposure. Thus, the radiation risk is very low compared to the benefits of the procedure. Nuclear medicine diagnostic procedures have been used for more than five decades, and there are no known long-term adverse effects from such low-dose exposure. For more information about safety in pediatric radiology procedures, visit the Image Gently™ website or you may print this brochure.
- Allergic reactions to radiopharmaceuticals may occur but are extremely rare and are usually mild. Nevertheless, you should inform the nuclear medicine personnel of any allergies your child may have or other problems that may have occurred during a previous nuclear medicine exam.
GETTING THE RESULTS
The images will be reviewed and interpreted by a pediatric radiologist who specializes in reading images of infants of children. The radiologist will send a report to, or speak directly with your child’s physician, who will discuss and explain the results of the exam with you. Results are usually available from your child’s doctor in 2 to 3 days.