Nuclear medicine procedures, commonly called "scans,"
provide information about the anatomy of the body and the
function of its organs. Nuclear medicine encompasses a wide
variety of diagnostic tests. With nuclear medicine, we can
produce images of nearly every organ system.
Your nuclear medicine procedure has been designed and is
monitored by a team of specially trained radiologists here
at SIRA, pharmacists who oversee the special chemical
compounds required, and technologists who perform the exams.
Most nuclear exams require an I.V. injection or sometimes an
oral ingestion of a radiopharmaceutical. A large detector
called a Gamma Camera is focused on the area we are
studying, allowing us to obtain digital images.
In principle, the gamma camera can be thought of as a
"reverse x-ray.” In a conventional x-ray exam, the radiation
is emitted from a machine and is passed through the patient
to a film or detector. In nuclear medicine, the administered
radiation comes from the patient and is collected by the
detector to create an image.
In general, conventional radiography is better at seeing
anatomical detail, while nuclear exams are used to look at
physiologic function, or how things work.
In a nuclear medicine diagnostic scan, you will be given a
special chemical compound which contains a tiny amount of a
radioactive isotope. You will take this either by mouth,
injection, or inhalant, depending upon the sort of compound
that you need. The compound will travel to the parts of your
body that we need to look at and it concentrates there. When
the scanner takes its pictures, it is really scanning for
the radioactive isotope. The scanner itself does not emit
any radiation, but your own body will!
Unless you are instructed otherwise by your physician, there
is nothing that you have to do to prepare for the exam. Most
of the exams require no preparation. You may be asked to
change into a gown and your personal belongings may be kept
in a locker.
You will be asked some questions about your medical history.
You must tell your technologist if you are pregnant, if you
may be pregnant, or if you are breastfeeding a baby.
As with any test using ionizing radiation, we avoid routine
scanning of pregnant women. Any woman who is breastfeeding
must refrain from nursing for at least 24 to 36 hours,
depending upon the type of scan.
After the administration of the compound, you may be asked
to wait a period of time before your scan begins. This
waiting time will vary for different kinds of scans. Some
may be performed almost immediately, while others may not
take place for a number of hours or even days after you get
the drug. (You don't have to wait the whole time at our
office.) This waiting period is necessary because it takes
time for the compounds we use in nuclear medicine to
accumulate in the part of your body being studied.
Here is a list of pre-scan procedures for some of our tests:
Bone scan: When you report, the technologist will
inject the radiopharmaceutical into a vein. In 2 to 4 hours,
you will return for scanning. The test itself usually takes
about 45 minutes.
Cholescintigraphy (also may be called a HIDA,
hepatobiliary, gallbladder ejection fraction, or biliary
excretory scan): You may have nothing to eat or drink after
midnight the night before your exam. Normally the exam takes
about ninety minutes.
Iodine-123 thyroid uptake & scan: You must be off any
thyroid medication (Synthroid, for example) for 6 weeks
prior to the test) and you should not have had a recent
contrast procedure using iodinated dye. These include such
tests as IVP and CT with contrast. You must have nothing to
eat or drink after midnight the night before your test. You
will swallow a capsule and then return to the Center in
about 6 hours for your scan. You must also report for more
scanning the next day. If you have any questions about
pre-scan procedures please call SIRA.
The term "Nuclear Medicine" often awakens deep-seated fears
in people, stirring up long-forgotten images of mushroom
clouds and duck-and-cover drills. Because of this, many
anxious patients only half-jokingly ask, "Will I glow in the
dark?" The truth is that this diagnostic modality actually
uses very small amounts of radiation.
The safety of nuclear medicine compares favorably to that of
other diagnostic imaging tests. The amounts of radiation you
get in your body from a procedure are about the same or less
than that which you get from an x-ray. Our well-trained
technologists and overseeing physicians make sure that
everything about the procedure is as safe as possible.
Side effects to the medical compounds that you will be given
are very rare and the compounds are eliminated quickly from
your body.
You may resume your normal routine of activities after your
exam. If you have had to stop taking regular medicines prior
to the exam, you will want to check with your doctor to see
when you should start taking them again.
Our nuclear medicine physician will analyze the various
pictures that are taken during your scan. The physician will
then compare these pictures with the results of other tests,
to reach a clear diagnosis of your medical situation.
