| Pediatric Nuclear Medicine
What is Pediatric Nuclear Medicine? Back to Top
Nuclear
medicine is a subspecialty within radiology that utilizes radioactive
substances to create images of body anatomy and function. The images
are developed based on the detection of energy emitted from the
radioactive substance given to the patient. Pediatric nuclear medicine
refers to these types of examinations in babies, young children and
teenagers.
What are some common uses of the procedure? Back to Top
Pediatric
nuclear medicine is used in the diagnostic workup of many childhood
disorders that are congenital (present at birth) or acquired later. It
helps in the evaluation of different organ systems, including the
kidneys, liver, heart, lungs and bones. Examples of how nuclear
medicine may be used in children include the diagnosis of urinary
blockage in the kidney, infections and trauma in the bones,
gastrointestinal bleeding, and various tumors and their sites of spread
in the body.
How should my child be prepared for the procedure? Back to Top
Most
studies will involve an intravenous injection. Parents or legal
guardians are urged to speak with their child, depending on the child's
age, before the procedure and tell them they will be getting a "shot."
For infants and toddlers, if sedation is anticipated, such as for a
bone scan, instructions for your child regarding eating and drinking
will be given at the time the appointment is made. Also, reassure your
child that you will be able to be in the room with them during the
procedure (except in case of pregnancy).
If the procedure involves examination of the stomach, your child
will have to fast for a certain period of time before the test. If the
procedure involves examination of the kidneys, your child should drink
plenty of water before the test.
What does the equipment look like? Back to Top
During most
nuclear medicine examinations, the child lies on a scanning table. The
gamma camera is enclosed in a metallic housing designed to facilitate
imaging of specific parts of the body. The camera is usually beneath
the table, out of view. Sometimes, when it is placed over the table it
can look like a large round metallic apparatus suspended from a tall,
moveable post, or a sleek one-piece metal arm that hangs over the
examination table. The camera can also be located within a large,
doughnut-shaped scanner similar in appearance to a computed tomography
(CT) scanner.
A nearby computer console, usually in the same room, develops the images from the data obtained by the camera.
How does the procedure work? Back to Top
With regular
x-rays, an image of the body is made by applying radiation to the body
part from the outside by an x-ray machine. However, with nuclear
medicine, a radioactive substance, called a "radiopharmaceutical" or
"radiotracer," is introduced into the body, usually intravenously or
sometimes orally. This radiotracer localizes in a certain body part(s),
which gives off gamma rays that are then detected by a gamma camera.
The gamma camera works in conjunction with a computer to develop an
image. The type of radiotracer used depends on the specific body part
being studied. The amount given is determined according to the child's
body weight. Depending on the type of scan, it may take several seconds
to several days for the substance to travel through the body and
accumulate in the organs under study; thus, a wide range in scanning
times is possible. The most commonly used radiopharmaceutical loses its
radioactivity generally over 24 hours. It passes out of the body in the
urine or stool.
How is the procedure performed? Back to Top
The child is
taken into the scanning room by a nuclear medicine technologist. Next,
the child is positioned on the scanning table. Then, a
radiopharmaceutical is administered by injection into a vein. Depending
on which type of scan is being performed, the imaging will be done
either immediately or a few hours or even two days after the injection.
Scanning time varies, generally from 20 to 45 minutes.
The gamma camera moves slowly along or around the child to obtain
images of the part of the body being examined. Sometimes sequential
images are obtained to show how an organ functions over time—for
example, the kidneys.
Immediately after the procedure, a physician with specialized
training in nuclear medicine—a nuclear medicine physician—checks the
quality of the images to ensure that an optimal diagnostic study has
been performed.
The same procedure will be followed if the radiopharmaceutical is given orally.
What will my child experience during the procedure? Back to Top
Some
discomfort during a nuclear medicine procedure may arise from the
intravenous injection, which is usually done with a small needle. With
some exams, a catheter may be placed into the bladder, which may cause
some temporary discomfort. Lying still on the examining table may be
unpleasant for some patients.
Unfortunately, many children fear any visit to a medical center.
This fear is sometimes made worse when they see strange machinery and
do not understand how it works. Most healthcare personnel who deal
extensively with children know how to calm a child's fears. Many
imaging suites have videotapes or toys on hand to help a child pass the
time. Often, a child can bring a favorite toy to the examination room.
Parents are encouraged to stay with the child to help calm the child
and decrease the child's motion during imaging.
Sedation may be needed in children younger than 4 years of age for
specific studies that take 30 to 45 minutes to complete or for which
body motion may severely degrade the images. The sedation is usually
oral, however may be intravenous, depending on the child's weight.
Unless the child has been sedated, daily activities can be resumed
after the nuclear medicine examination.
Who interprets the results and how do we get them? Back to Top
Most
children undergo a nuclear medicine examination because a referring
physician, often the primary care physician, has recommended it. The
nuclear medicine physician will interpret the images and forward a
report to the referring physician. It usually takes one to three days
to interpret, report and deliver the results.
What are the benefits vs. risks? Back to Top
The functional
information provided by nuclear medicine examinations is unique and
currently unattainable by using other imaging procedures. For certain
diseases, nuclear medicine studies yield the most useful information
needed to make a diagnosis. Pediatric nuclear medicine procedures
will result in exposure of the child to a small dose of radiation.
However, the doses of radiopharmaceutical administered are the smallest
needed to perform the examination. Nuclear medicine has been used in
newborns and children for more than three decades, and there are no
known long-term adverse effects from such low-dose studies. Allergic reactions to the radiopharmaceutical may occur, but are extremely rare.
What are the limitations of Pediatric Nuclear Medicine? Back to Top
Nuclear
medicine procedures can be time-consuming. They involve administering a
radiotracer, waiting for it to settle in the body part, and then
obtaining the images. In some studies, imaging times may be lengthy,
requiring sedation for young patients. However, new gamma cameras have
been introduced that can cut down imaging time.
The resolution of structures of the body with nuclear medicine may
not be as clear as with other imaging techniques, such as CT or MRI.
However, the functional information gained from nuclear medicine is
unequaled in other imaging techniques. Back to Top |
