What A Person Experiences, What to Expect During a Nuclear Medicine Study
Many nuclear medicine examinations
are similar and follow these general clinical guidelines:
Various nuclear medicine studies require
special preparation before the patient arrives such as fasting or taking pharmaceutical
tablets in advance of the exam examination. Patients should inquire with the imaging
center or imaging department they are scheduled to visit a few days in advance of their
nuclear medicine study about specific preparations they may need to follow.
Patient preparation involves removing
any articles of clothing or jewelry that may interfere with the imaging procedure. In some
cases, the patient may be asked to wear a patient gown. Before the examination, patients
should inform the physician or technologist if they have any prosthetic implants in their
body.
In all nuclear medicine studies, a
pharmaceutical radionuclide is administered either orally or via injection
(intravenously).
The type and dose of the pharmaceutical
radionuclide to be administered is based on the patient's current, accurate body weight
and the organ to be imaged.
Patients should inform the physician or
technologist if they have a history of allergies and of any current medication they may be
taking.
Diabetic patients should alert the
physician or technologist of their condition.
Patients who are pregnant or may suspect
that they are pregnant (or who are breast feeding a baby) should inform their
physician before undergoing any nuclear medicine or medical imaging study.
A patient undergoes an abdominal
nuclear medicine study
Often, the patient is imaged shortly
after the administration of the radionuclide, but occasionally the patient may be asked to
return 30 minutes to four hours after administration of the radionuclide, to begin the
imaging process. For some exams, the radionuclide will be administered the day before the
exam. This allows time for the radionuclide to be "taken up" by the specific
organ(s) being imaged. Different organs take up or absorb the radionuclide at different
rates.
The patient is positioned by the
technologist on an examination table. Some nuclear medicine studies allow the patient to
be seated. The nuclear medicine camera is then positioned over the area of interest, for
example, the heart. Some nuclear medicine cameras have a patient aperture ("doughnut
hole") like a CT scanner and the patient is positioned inside of this aperture for
the study. The patient is simply required to relax and stay calm during the examination.
During the nuclear medicine examination, the technologist and patient can communicate at
any time.
After the examination, which can last
from 15 to 60 minutes, the technologist will ask the patient to get dressed and wait while
the nuclear medicine images are reviewed (either on film or a computer monitor).
Nuclear medicine "stress
tests" involve exercise on a treadmill or stationary bicycle, followed by a nuclear
medicine acquisition. After a sufficient period of rest, a second acquisition is made to
acquire images of the heart at rest. Occasionally when exercise is contraindicated or not
recommended for a patient, "stress" to the heart may be accomplished by the
administration of medication. Patients who will undergo a stress test should wear low
healed, rubber-soled shoes or tennis shoes and comfortable clothing that will allow them
to walk on the treadmill as required. This will make the exam easier for most patients.
After the nuclear medicine images are
reviewed, the patient will be released from the imaging department or center. In some
cases, more images will need to be taken. For more information see "what happens during a diagnostic imaging examination?"
Patients retain the low level
radioactivity administered during a radionuclide study for relatively short periods. The
radiation doses involved are so low that a person accompanying a patient can stay with
them throughout the day. For example, with bone scans studies, patients can leave while
the radionuclide distributes in their body and come back
several hours later for the procedure.
The radioactive energy dissipates on
its own, and some of the radiation is eliminated through urine or bowel movement. The
result is that the radioactive material is only in the patient for a short time. Once the
energy is eliminated, patients no longer carry the radioactivity. The levels of radiation
involved in most nuclear medicine studies are usually considerably lower than a patient
would receive in a conventional x-ray study or CT scan. Approximately 12 million nuclear
medicine exams are performed in the U.S. each year.
Time lapsed photo showing tabletop motion of patient undergoing a bone scan. The gamma
camera (arrow) remains stationary while the table top and patient move slowly.