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What is Nuclear Medicine?
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**NEW**
What Is PET information added to the website 6/25/02
Nuclear medicine is a medical specialty that uses safe, painless, and
cost-effective techniques both to image the body and treat disease.
Nuclear medicine imaging is unique in that it documents organ
function and structure, in contrast to diagnostic radiology, which is
based upon anatomy. It is a way to gather medical information that
may otherwise be unavailable, require surgery, or necessitate more
expensive diagnostic tests.
As an integral part of patient care, nuclear medicine is used in the
diagnosis, management, treatment, and prevention of serious
disease. Nuclear medicine imaging procedures often identify
abnormalities very early in the progression of a disease -long before
some medical problems are apparent with other diagnostic tests.
This early detection allows a disease to be treated early in its course when there may be a more
successful prognosis.
Nuclear medicine uses very small amounts of radioactive materials or radiopharmaceuticals to
diagnose and and treat disease. Radiopharmaceuticals are substances that are attracted to
specific organs, bones, or tissues. The radiopharmaceuticals used in nuclear medicine emit
gamma rays that can be detected externally by special types of cameras: gamma or PET
cameras. These cameras work in conjunction with computers used to form images that provide
data and information about the area of body being imaged. The amount of radiation from a
nuclear medicine procedure is comparable to that received during a diagnostic x-ray.
Today, nuclear medicine offers procedures that are helpful to a broad span of medical specialties,
from pediatrics to cardiology to psychiatry. There are nearly one hundred different nuclear
medicine imaging procedures available and not a major organ system which is not imaged by
nuclear medicine.
What Patients Should Know About Nuclear Medicine Procedures
Your doctor has referred you or a family member for a test in the nuclear medicine department
because the information obtained from the test will be important in determining the diagnosis and
treatment of the medical problem you may have. You probably have a number of questions such
as:
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What is a nuclear medicine test?
What preparation is needed for the test?
What will happen during the test?
This section provides information on some of the more commonly performed diagnostic and
therapeutic nuclear medicine procedures. First, an overview of nuclear medicine is discussed;
answers to frequently asked questions as well as key points to know are provided. Lastly,
procedures for specific tests are outlined.
However, the material presented here is for informational purposes only and is not intended as a
substitute for discussion between you and your physician. If you require more information about a
nuclear medicine procedure, please consult your physician or the nuclear medicine department of
the institution where the test will be performed.
What Is Nuclear Medicine?
Nuclear medicine involves the use of small amounts of radioactive materials (or tracers) to help
diagnose and treat a variety of diseases. Nuclear medicine determines the cause of the medical
problem based on the function of the organ, tissue or bone. This is how nuclear medicine differs
from an x-ray, ultrasound or other diagnostic test that determines the presence of disease based
on structural appearance.
Millions of nuclear medicine tests are performed each year in the United States alone. Nuclear
medicine tests (also known as scans, examinations, or procedures) are safe and painless. In a
nuclear medicine test, the radioactive material is introduced into the body by injection,
swallowing, or inhalation. Different tracers are used to study different parts of the body. The
amount of tracer used is carefully selected to provide the least amount of radiation exposure to
the patient but ensure an accurate test. A special camera (scintillation or gamma camera) is used
to take pictures of your body. The camera does this by detecting the tracer in the organ, bone or
tissue being imaged and then records this information on a computer screen or on film. Generally,
nuclear medicine tests are not recommended for pregnant women because unborn babies have a
greater sensitivity to radiation than children or adults. If you are pregnant or think that you are
pregnant, your doctor may order a different type of diagnostic test.
Careers in Nuclear Medicine: Physicians Technologists Pharmacist Job Bank
Nuclear physicians are usually based in a university or hospital, or both, and have limited
involvement in direct patient care. Nuclear Medicine physicians participate in the intellectual
challenge presented in assisting with the formulation of patient diagnoses and treatment
wherever indicated. This specialty offers clinical variety, freedom to conduct research and make
original observations.
The nuclear medicine technologist is a specialized healthcare professional who works directly
with patients during an imaging procedure and works closely with the nuclear medicine physician.
A nuclear pharmacist specializes in the procurement, compounding, quality control testing,
dispensing, distribution, and monitoring of radiopharmaceuticals. They also provide consultation
regarding health and safety issues as well as the use of non-radioactive drugs and patient care.
The History Of Nuclear Medicine
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Also see: JNM's Newsline History Corner Archives
Nuclear medicine has a complex and multifaceted heritage. Its origins stem from many scientific
discoveries, most notably the discovery of x-rays in 1895 and the discovery of "artificial
radioactivity" in 1934. The first clinical use of "artificial radioactivity" was carried out in 1937 for
the treatment of a patient with leukemia at the University of California at Berkeley.
A landmark event for nuclear medicine occurred in 1946 when a thyroid cancer patient's
treatment with radioactive iodine caused complete disappearance of the spread of the patient's
cancer. This has been considered by some as the true beginning of nuclear medicine. Widespread clinical use of nuclear medicine, however, did not start until the early 1950s.
The value of radioactive iodine became apparent as its use increased to measure the function of
the thyroid and to diagnose thyroid disease. Simultaneously, more and more physicians begin to
use "nuclear medicine" for the treatment of patients with hyperthyroidism. The concept of nuclear
medicine was a dramatic breakthrough for diagnostic medicine. Moreover, the ability to treat a
disease with radiopharmaceuticals and to record and make a "picture" of the form and structure
of an organ was invaluable.
In the mid-sixties and the years that followed, the growth of nuclear medicine as a specialty
discipline was phenomenal. The advances in nuclear medicine technology and instrument
manufacturers were critical to this development.
The 1970s brought the visualization of most other organs of the body with nuclear medicine,
including liver and spleen scanning, brain tumor localization, and studies of the gastrointestinal
track.
The 1980s provided the use of radiopharmaceuticals for such critical diagnoses as heart disease
and the development of cutting-edge nuclear medicine cameras and computers. Today, there are
nearly 100 different nuclear medicine procedures that uniquely provide information about virtually
every major organ system within the body. Nuclear medicine is an integral part of patient care,
and an important diagnostic and therapeutic specialty in the armamentarium of medical science.
Important Dates in the History of Nuclear Medicine
1896 Henri Becquerel discovered mysterious "rays" from uranium.
1897 Marie Curie named the mysterious rays "radioactivity."
1901 Henri Alexandre Danlos and Eugene Bloch placed radium in contact with a tuberculous
skin lesion.
1903 Alexander Graham Bell suggested placing sources containing radium in or near tumors.
1913 Frederick Proescher published the first study on the intravenous injection of radium for
therapy of various diseases.
1924 Georg de Hevesy, J.A. Christiansen and Sven Lomholt performed the first radiotracer
(lead-210 and bismuth-210) studies in animals.
1932 Ernest O. Lawrence and M. Stanley Livingston published the first article on "the production
of high speed light ions without the use of high voltages." It was a milestone in the
production of usable quantities of radionuclides.
1936 John H. Lawrence, the brother of Ernest, made the first clinical therapeutic application of
an artificial radionuclide when he used phosphorus-32 to treat leukemia.
1937 John Livingood, Fred Fairbrother and Glenn Seaborg discovered iron-59. 1938 John
Livingood and Glenn Seaborg discovered iodine-131 and cobalt-60.
1939 Emilio Segre and Glenn Seaborg discovered technetium-99m.
1940 The Rockefeller Foundation funded the first cyclotron dedicated for biomedical radioisotope
production at Washington University in St. Louis.
1946 Samuel M. Seidlin, Leo D. Marinelli and Eleanor Oshry treated a patient with thyroid cancer
with iodine-131, an "atomic cocktail."
1947 Benedict Cassen used radioiodine to determine whether a thyroid nodule accumulates
iodine, helping to differentiate benign from malignant nodules.
1948 Abbott Laboratories began distribution of radioistopes.
1950 K.R. Crispell and John P. Storaasli used iodine-131 labeled human serum albumin (RISA)
for imaging the blood pool within the heart.
1951 The U.S. Food and Drug Administration (FDA) approved sodium iodide 1-131 for use with
thyroid patients. It was the first FDA-approved radiopharmaceutical.
1953 Gordon Brownell and H.H. Sweet built a positron detector based on the detection of
annihilation photons by means of coincidence counting.
1954 David Kuhl invented a photorecording system for radionuclide scanning. This development
moved nuclear medicine further in the direction of radiology.
1955 Rex Huff measured the cardiac output in man using iodine-131 human serum albumin.
1958 Hal Anger invented the "scintillation camera," an imaging device that made it possible to
conduct dynamic studies.
1960 Louis G. Stang, Jr., and Powell (Jim) Richards advertised technetium-99m and other
generators for sale by Brookhaven National Laboratory. Technetium-99m had not yet been
used in nuclear medicine.
1962 David Kuhl introduced emission reconstruction tomography. This method later became
known as SPECT and PET. It was extended in radiology to transmission X-ray scanning,
known as CT.
1963 The FDA exempted the "new drug" requirements for radiopharmaceuticals regulated by the
Atomic Energy Commission.
Henry Wagner first used radiolabeled albumin aggregates for imaging lung perfusion in
normal persons and patients with pulmonary embolism.
1969 C.L. Edwards reported the accumulation of gallium-67 in cancer. 1970 The FDA
announced that it would gradually withdraw the exemption granted to radiopharmaceuticals
and start regulating them as drugs. The change would be completed by Jan. 20, 1977.
1971 The American Medical Association officially recognized nuclear medicine as a medical
speciality.
1973 H. William Strauss introduced the exercise stress-test myocardial scan.
1976 John Keyes developed the first general purpose single photo emission computed
tomography (SPECT) camera. Ronald Jaszczak developed the first dedicated head
SPECT camera.
1978 David Goldenberg used radiolabeled antibodies to image tumors in humans.
1981 J.P. Mach used radiolabeled monoclonal antibodies for tumor imaging.
1982 Steve Larson and Jeff Carrasquillo treated cancer patients with malignant melanoma using
iodine-131 labeled monoclonal antibodies.
1989 The FDA approved the first positron radiopharmaceutical (rubidium-82) for myocardial
perfusion imaging.
1992 The FDA approved the first monoclonal antibody radiopharmaceutical for tumor imaging.
Benefits Of Nuclear Medicine
Nuclear medicine is a safe, painless, and cost-effective way of gathering information that may
otherwise be unavailable or require more expensive and risky diagnostic test. A unique aspect of
a nuclear medicine test is its extreme sensitivity to abnormalities in an organ's structure or
function. As an integral part of patient care, nuclear medicine is used in the diagnosis,
management, treatment and prevention of serious disease. Nuclear medicine imaging procedures
often identify abnormalities very early in the progression of a disease --long before some medical
problems are apparent with other diagnostic test. This early detection allows a disease to be
treated early in its course when there may be a more successful prognosis.
Although nuclear medicine is commonly used for diagnostic purposes, it also has valuable
therapeutic applications such as treatment of hyperthyroidism, thyroid cancer, blood imbalances,
and pain relief from certain types of bone cancer.
Safety of Nuclear Medicine
Nuclear medicine procedures are among the safest diagnostic imaging exams available. A patient
only receives an extremely small amount of a radiopharmaceutical, just enough to provide
sufficient diagnostic information. In fact, the amount of radiation from a nuclear medicine
procedure is comparable to, or often times less than, that of a diagnostic x-ray.
Although we don't think much about it, everyone is continually exposed to radiation from natural
and manmade sources. For most people, natural background radiation from space, rocks, soil,
and even carbon and potassium atoms in his or her own body, accounts for 85 percent of their
annual exposure. Additional exposure is received from consumer products such as household
smoke detectors, color television sets, and luminous dial clocks. The remainder is from x-rays
and radioactive materials used for medical diagnosis and therapy. With most nuclear medicine
procedures, the patient receives about the same amount of radiation as that acquired in a few
months of normal living.
Because of his or her special training, the nuclear medicine physician is able to select the most
appropriate examination for the patient's particular medical problem, and thereby avoid any
unnecessary radiation exposure.
Nuclear Medicine Procedures
A Partial List of Why Physicians Order Nuclear Medicine Studies
Neurologic Applications:
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Diagnose Stroke
Diagnose Alzheimer's Disease
Demonstrate Changes in AIDS Dementia
Evaluate Patients for Carotid Surgery
Localize Seizure Foci
Evaluate Post Concussion Syndrome
Diagnose Multi-Infarct Dementia
Oncologic Applications:
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Tumor Localization
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Tumor Staging
Identify Metastatic Sites
Judge Response to Therapy
Relieve Bone Pain Caused by Cancer
Orthopedic Applications:
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Identify Occult Bone Trauma (Sports Injuries)
Diagnose Osteomyelitis
Evaluate Arthritic Changes and Extent
Localize Sites for Biopsy in Tumor Patients
Measure Extent of Certain Tumors
Identify Bone Infarcts in Sickle Cell Disease
Renal Applications:
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Detect Urinary Tract Obstruction
Diagnose Renovascular Hypertension
Measure Differential Renal Function
Detect Renal Transplant Rejection
Detect Pyelonephritis
Detect Renal Scars
Cardiac Applications:
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Diagnose Coronary Artery Disease
Measure Effectiveness of Bypass Surgery
Measure Effectiveness of Therapy for Heart Failure
Detect Heart Transplant Rejection
Select Patients for Bypass or Angioplasty
Identify Patients at High Risk of Heart Attacks going to Surgery for Other Reasons
Identify Right Heart Failure
Measure Chemotherapy Cardiac Toxicity
Evaluate Valvular Heart Disease
Identify Shunts and Quantify Them
Diagnose and Localize Acute Heart Attacks Before Enzyme Changes
Pulmonary Applications:
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Diagnose Pulmonary Emboli
Detect Pulmonary Complications of AIDS
Quantify Lung Ventilation and Perfusion
Detect Lung Transplant Rejection
Detect Inhalation Injury in Burn Patients
Other Applications:
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Diagnose and Treat Hyperthyroidism (Grave's Disease)
Detect Acute Cholecystitis
Detect Acute Gastrointestinal Bleeding
Detect Testicular Torsion
Detect Occult Infections
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Diagnose and Treat Blood Cell Disorders
See Patient Information for more details on specific nuclear medicine procedures.
What Is PET
Positron Emission Tomography (PET) is rapidly becoming a major diagnostic imaging modality
used predominantly in determining the presence and severity of cancers, neurological conditions,
and cardiovascular disease. It is currently the most effective way to check for cancer recurrences.
Studies demonstrate that PET offers significant advantages over other forms of imaging such as
CT or MRI scans in diagnosing disease. Last year more than 200,000 PET scans were performed
at more than 700 sites around the country. If you're interested in learning how a PET scan can
benefit you and need additional information, talk with your local health care provider or referring
physician. At the end of this page are links to other sites with PET information too.
PET images demonstrate the chemistry of organs and other tissues such as tumors. A
radiopharmaceutical, such as FDG (fluorodeoxyglucose), which includes both sugar (glucose)
and a radionuclide (a radioactive element) that gives off signals, is injected into the patient and its
emissions are measured by a PET scanner.
A PET scanner consists of an array of detectors that surround the patient. Using the gamma ray
signals given off by the injected radionuclide, PET measures the amount of metabolic activity at a
site in the body and a computer reassembles the signals into images. Cancer cells have higher
metabolic rates than normal cells, and show up as denser areas on a PET scan. PET is useful in
diagnosing certain cardiovascular and neurological diseases because it highlights areas with
increased, diminished or no metabolic activity, thereby pinpointing problems.
Cancer & PET
PET is considered particularly effective in identifying whether cancer is present or not, if it has
spread, if it is responding to treatment, and if a person is cancer free after treatment. Cancers for
which PET is considered particularly effective include lung, head and neck, colorectal,
esophageal, lymphoma, melanoma, breast, thyroid, cervical, pancreatic, and brain as well as
other less-frequently-occurring cancers.
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Early Detection: Because PET images biochemical activity, it can accurately
characterize a tumor as benign or malignant, thereby avoiding surgical biopsy when the
PET scan is negative. Conversely, because a PET scan images the entire body,
confirmation of distant metastasis can alter treatment plans in certain cases from surgical
intervention to chemotherapy.
Staging of Cancer: PET is extremely sensitive in determining the full extent of disease,
especially in lymphoma, malignant melanoma, breast, lung, colon and cervical cancers.
Confirmation of metastatic disease allows the physician and patient to more accurately
decide how to proceed with the patient's management.
Checking for recurrences: PET is currently considered to be the most accurate
diagnostic procedure to differentiate tumor recurrences from radiation necrosis or postsurgical changes. Such an approach allows for the development of a more rational
treatment plan for the patient.
Assessing the Effectiveness of Chemotherapy: The level of tumor metabolism is
compared on PET scans taken before and after a chemotherapy cycle. A successful
response seen on a PET scan frequently precedes alterations in anatomy and would
therefore be an earlier indicator of tumor response than that seen with other diagnostic
modalities.
PET and CT or MRI
Because PET measures metabolism, as opposed to MRI or CT, which "see" structure, it can be
superior to these modalities, particularly in separating tumor from benign lesions, and in
differentiating malignant from non-malignant masses such as scar tissue formed from treatments
like radiation therapy. PET is often used in conjunction with an MRI or CT scan through "fusion"
to give a full three-dimensional view of an organ and the location of cancer within that organ.
Newer PET scanners are being made that are a combination of PET/CT devices.
Neurological Disease
PET's ability to measure metabolism also has significant implications in diagnosing Alzheimer's
disease, Parkinson's disease, epilepsy and other neurological conditions, because it can vividly
illustrate areas where brain activity differs from the norm.
Alzheimer's Diagnosis: Until recently, autopsy has been considered the only definitive test for
Alzheimer's disease (AD). Recent studies indicate that PET can supply important diagnostic
information and confirm an Alzheimer's diagnosis (Journal of Nuclear Medicine, November 2000).
When comparing a normal brain versus an AD-affected brain on a PET scan, a distinctive image
appears in the area of the AD-affected brain. This pattern is seen very early in the AD course.
Conventionally, the confirmation of AD is a long process of elimination that averages between two
and three years of diagnostic and cognitive testing. Early diagnosis can provide the patient
access to therapies, which are more effective earlier in the disease.
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PET also is useful in differentiating Alzheimer's disease from other forms of dementia
disorders, such as vascular dementia, Parkinson's disease, Huntington's disease, etc.
Epilepsy: PET is one of the most accurate methods available to localize areas of the
brain causing epileptic seizures and to determine if surgery is a treatment option.
Cardiovascular Disease
By measuring both blood flow (perfusion) and metabolic rate within the heart, physicians using
PET scans can pinpoint areas of decreased blood flow such as that caused by blockages, and
differentiate muscle damage from living muscle, which has inadequate blood flow (myocardial
viability). This information is particularly important in patients who have had previous myocardial
infarction and who are being considered for a revascularization procedure.
Cost & Reimbursement:
PET scan charges range from $1200-$3500, depending on the type of scan. Insurance
companies will cover the cost of many PET scans. Medicare reimburses for PET scans for the
following cancers: colorectal, lung, lymphoma, and melanoma, head and neck and esophageal
cancers, and also for refractory seizures (epilepsy). Medicare will begin PET reimbursement to
initially stage, to determine recurrence and to measure effectiveness of treatment of breast
cancer as well as for myocardial viability. These new reimbursement categories become effective
October 1, 2002. Medicare is constantly updating reimbursements, so visit the SNM website
(www.snm.org) to find the latest information.
History of PET
In the 1970's PET scanning was formally introduced to the medical community. At that time it was
seen as an exciting new research modality that opened doors through which medical researchers
could watch, study, and understand the biology of human disease.
In 1976, the radiopharmaceutical fluorine-18-2-fluoro-2-deoxyglucose (FDG), a marker of sugar
metabolism with a half-life of 110 minutes, enabled tracer doses to be administered safely to the
patient with low radiation exposure. The development of radiopharmaceuticals like FDG made it
easier to study living beings, and set the groundwork for more in-depth research into using PET
to diagnose and evaluate the effect of treatment on human disease. To perform PET studies in
the late 1970's, a large staff was needed: physicists to run the cyclotron that produces the F-18
and to oversee the scanner, chemists to make the tracers such as FDG, and dedicated, specialist
physicians.
During the 1980's the technology that underlies PET advanced greatly. Commercial PET
scanners were developed with more precise resolution and images. As a result, many of the
steps required for producing a PET scan became automated, and able to be performed by a
trained technician and experienced physician, thereby reducing the cost and complexity of the
procedure. Smaller, self-shielded cyclotrons were developed, making it possible to install
cyclotrons at more locations.
PET Today
Until recently a PET center required a cyclotron and a radiochemistry laboratory on site to
produce the FDG. As a result there was a scarcity of centers. However, there are now multiple
sites that make FDG and distribute it to the centers that only need to have a PET scanner to
perform the imaging study.
Radionuclide Imaging Overview
Section 1 of 1
(Radioisotope Scanning, Radionuclide Isotope Injection, Nuclear Imaging, Myocardial Perfusion
Imaging, Perfusion Imaging)
Edited By Robert I. Hamby, M.D., FACC, FACP
Visit The Radionuclide Imaging Center
Radionuclide imaging is a technique that allows physicians to obtain very clear images of
various parts of the body, such as the heart. To obtain these images, tiny amounts of
radioactive materials (called "tracers") are introduced into the patient’s body. The tracers
emit a certain type of energy called gamma rays, which are detected by machines. For
example, a positron emission tomography (PET) scan uses machines called
photomultiplier-scintillator detectors to detect the gamma rays. Other tests, such as a
nuclear stress test or single photon emission computed tomography (SPECT), use
a gamma camera to detect the energy. The information detected and recorded by these
machines is then analyzed and reconstructed by computers to create very clear images
of the target area of the patient’s body.
For most people, the tracer is harmless and is flushed from the body after the test.
However, there are a number of people who should avoid radionuclide imaging. These
include women who are pregnant or breast-feeding. Other patients who should avoid this
type of test include those with the following conditions:
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Inflammation of the heart muscle (myocarditis)
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Recent pulmonary (lung) infection
Coarctation of the aorta
Severe narrowing (stenosis) of the aortic valve
Severe heart failure
Nuclear Stress Test
Section 1 of 4 Next
(Cardiac Stress Imaging, Exercise Myocardial Perfusion Imaging, Radionuclide Stress Test,
Thallium Stress Test, Thallium Treadmill Test, Myoview, Thallium Exercise Scan, Thallium
Imaging)
Edited By Lee B. Weitzman, M.D, FACC, FCCP
Summary
What is a nuclear stress test?
How does the nuclear component of a stress test work?
How does a patient prepare for a nuclear stress test?
How is a nuclear test done?
What happens after the nuclear stress test?
Visit The Radionuclide Imaging Center
Summary
An exercise stress test is a special type of
electrocardiogram (EKG) that compares
the heart’s electrical activity at rest and
under exertion. Sometimes an additional
component needs to be done during the
stress test in order to determine which parts
of the heart are healthy and functioning, and
which are not. If this additional component is
ordered, then the test is called a nuclear
stress test.
In addition to the procedures that are
performed as part of a standard stress test, a
patient scheduled for a nuclear stress test is
injected with a very small, harmless amount
of a radioactive (radionuclide) substance,
such as thallium. Once in the patient's body,
this substance emits rays that can be picked up by a special (gamma) camera. The rays
allow the camera to produce clear pictures of heart tissue on a video monitor. These
pictures show contrasts between light and dark spots, which can indicate areas of
damage or reduced blood flow that are present before, during and after exertion.
Aside from some slight discomfort that may be felt when the radionuclide substance is
injected (twice), this is a painless test. Patients are generally asked not to eat or drink
anything for four to six hours before the test, and to wear comfortable clothes/shoes for
exercising. The time needed for the test will vary because different facilities use slightly
different strategies for taking pictures of the heart at rest and during some form of
exercise. Patients are encouraged to speak with their physician about how long the test
will take. After the test, they can return to their usual daily activities immediately.
Depending on what is found during the nuclear stress test, the physician is often able to
make a diagnosis and treatment plan for the patient. Further testing or procedures may
need to be done.
SPECT Scan
Section 1 of 5 Next
(Single Photon Emission Computed Tomography , SPECT, Emission Computed Tomography,
ECT, Gated SPECT Scan)
Edited By Stephen D. Shappell, M.D., FACC, FCCP, FACP
Summary
What is a SPECT scan?
How does a SPECT scan work?
What types of cardiac SPECT scans are available?
How is a SPECT scan done?
What happens after a SPECT scan?
What tests may be ordered after a SPECT scan?
Visit The Radionuclide Imaging Center
Summary
Single photon emission computed tomography (SPECT) is a noninvasive technique for
creating very clear, three-dimensional pictures of a major organ (e.g., the heart). SPECT
scans use radionuclide imaging – a technique that involves the injection of very small
amount of a radionuclide substance called a tracer. Energy from the tracer in the body is
detected by a gamma ray camera, which then takes the pictures. A tracer is not a dye
(contrast medium).
People may experience some slight discomfort from the needle used to insert an
intravenous (I.V.) line in the crook of their arm, which is necessary to give the patient
the tracer. Otherwise, these tests are painless.
Although the tracer is flushed harmlessly from the bodies of most people in about 48
hours, there are some people (e.g., pregnant or breast-feeding women) who should not
have a radionuclide test. People are encouraged to discuss with their physician any
concerns they may have about radiation.
MUGA Scan
Section 1 of 4 Next
(Multi Gated Acquisition Scan, First Pass Scan, Gated Blood Pool Scan, Cardiac Blood Pooling
Imaging, Radionuclide Ventriculography, Nuclear Ventriculography)
Edited By Ronald D. D'Agostino, D.O., FACC
Stephen D. Shappell, M.D., FACC, FCCP, FACP
Summary
What is a MUGA scan?
How does a patient prepare for a MUGA scan?
How is a MUGA scan done?
What happens after a MUGA scan?
What do the results of a MUGA scan mean?
Visit The Radionuclide Imaging Center
Summary
Also known as a nuclear ventriculogram, a multi-gated acquisition (MUGA) scan is a type
of radionuclide imaging that provides the physician with a comprehensive look at
blood flow and the function of the lower chambers of the heart (ventricles). It involves
very small amounts of a radioactive isotope called a tracer, which is administered
through an intravenous (I.V.) line. The substance travels through the bloodstream to the
heart, enabling a gamma camera to take very clear pictures of the heart tissues.
People may experience some slight discomfort from the needle used to insert the
intravenous (I.V.) line, usually in the crook of the arm. Otherwise, these tests are
painless. If the physician has also ordered an exercise component of the test, then some
preparation will be necessary, such as wearing appropriate clothes and shoes for
exercising.
Although the tracer is flushed harmlessly from the bodies of most people in about 48
hours, there are some people (e.g., pregnant or nursing women) who should not have a
radionuclide test. People are encouraged to discuss with their physician any concerns
they may have about radiation.
PET Scan
Section 1 of 4 Next
(Positron Emission Tomography)
Edited By Lee B. Weitzman, M.D, FACC, FCCP
Andrew I. Lituchy, M.D., FACC
Summary
What is a positron emission tomography (PET) scan?
How does a patient prepare for a PET scan?
How is a PET scan done?
What happens after the PET scan?
What other tests may be ordered after a PET scan?
How does a PET scan work?
Visit The Radionuclide Imaging Center
Summary
A positron emission tomography (PET) scan is a unique noninvasive imaging technique
that can produce three-dimensional images of the living heart, brain or other organs at
work. PET scans are often used in the diagnosis and management of cancers, certain
brain disorders and heart disease. Cardiac PET scanning is generally similar to other
types of non-invasive stress tests to help determine the presence and extent of CAD. It
has two major advantages over the more common nuclear stress tests. First, the
images are less likely to be distorted by parts of the patient’s body (large breasts,
obesity etc.), so abnormal results are more reliable. Second, it is an excellent tool for
determining whether portions of the heart muscle are still viable (living and functioning).
The scan can also measure how well those viable portions are functioning after a heart
attack or other event in which there is a lack of oxygen-rich blood to the heart muscle.
PET scanning is not as readily available as more conventional nuclear imaging because of
its greater cost and the need for a cyclotron device, which produces necessary isotopes
on site.
Before the test, people are encouraged to 1) wear comfortable, loose clothing, 2) stop
eating or drinking for four hours before the test, and 3) discuss with their physician any
changes that need to be made in how they take their medication that day. During the
test, they may feel the needle prick when an intravenous (I.V.) line is inserted in their
arm to administer a small amount of radioactive material. Otherwise, the test is painless.
The test takes at least an hour to complete. Afterward, patients may drive themselves
home and go about their usual activities, drinking plenty of water to flush the radioactive
material from their body.
Nuclear Medicine Imaging Techniques
The following techniques are used in the diagnosis, management, treatment, and prevention of
disease. Nuclear medicine is unique in that it often allows for diagnostic information to be discerned
prior to the onset of physical symptoms.
Planar
Provides a two-dimensional view of the process or function of the organ being imaged.
SPECT
(Single Photon Emission Computed Tomography)
Provides 3-D computer-reconstructed images of multiple views and function of the organ being
imaged.
PET
(Positron Emission Tomography)
Produces high energy, 3-D computer-reconstructed images measuring and determining the
function or physiology in a specific organ, tumor, or other metabolically active site.
CT
(Computed Tomography)
shows organs of interest at selected levels of the body.
Tomography
From the Greek words "to cut or section" (tomos) and "to write" (graphein). A method of separating
interference from the area of interest by imaging a cut section of the object.
MRI
(Magnetic Resonance Imaging)
Produces images which are the visual equivalent of a slice of anatomy.
Nuclear Medicine Scan
The images produced as the result of a nuclear medicine procedure, often referred to as the actual
procedure, examination or test.
Radiopharmaceutical
Also referred to as tracer or radionuclide. The basic radioactively tagged compound necessary to
produce a nuclear medicine image.
Gamma Camera
The basic instrument used to produce a nuclear medicine image.
In Vitro
In vitro procedures are done in test tubes. Radioimmunoassay (RIA) is a special type of in vitro
procedure that combines the use of radiochemicals and antibodies to measure the levels of
hormones, vitamins, and drugs in a patient's blood.
In Vivo
In vivo procedures are when trace amounts of radiopharmaceuticals are given directly to a patient.
The majority of nuclear medicine procedures are in vivo.
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