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What are the health
benefits of nuclear medicine?
NUCLEAR facts
RADIATION IS WIDELY USED TODAY FOR PREVENTING, DIAGNOSING AND TREATING DISEASE.
Prevention
Over 40% of all disposable medical supplies are sterilized
using gamma radiation and most of this is by Canadianmade
irradiators. Hospital supplies such as sutures, masks,
surgical gloves, dressings, scalpel blades, catheters and
syringes are pre-packaged and passed through an irradiator
containing a large cobalt-60 source. The irradiation
process virtually eliminates all bacteria, viruses and other
living organisms that could threaten the sterile operating
room environment without damage to the product.
Irradiation, being a cold process, permits the sterilization
of heat-sensitive materials such as plastic, and is often the
only method of sterilizing some pharmaceutical powders,
ointments and solutions. There are more than 120 industrial
irradiators located around the world, a large number
of which were built by the Canadian company MDS
Nordion. This technology is also used to help make the
world’s food supply safer. Food irradiation has been
approved for use in some 40 countries to eliminate
harmful pathogens from many foods. (See Nuclear
Facts – "Why food irradiation?")
Diagnosis
Since the 1950s, radiation has been
increasingly used in numerous medical
diagnostic applications. Minute quantities
of radiation emitted by radioisotopes
are easy to detect and measure.
When radioisotopes are given to a
patient, the distribution, rate of
distribution and concentration of
that radioactive material can be
safely traced by detectors in
special cameras. There are over
100 diagnostic applications using
medical isotopes. Diagnostic tests
employing radioisotopes are used
to determine how well organs function;
how the body absorbs certain
substances; and how to locate and
delineate tumors, often eliminating the need for
exploratory surgery. Millions of diagnostic procedures
are carried out each year using Canadian-produced
radioisotopes.
The most widely used medical radioisotope for diagnostic
medical purposes is technetium-99m, largely because its
short half-life of only six hours limits the radiation dose
to the patient and the energy of its gamma rays is ideally
suited for diagnosis. MDS Nordion is the major supplier
of molybdenum-99, which decays (changes) into technetium99m. This company supplies nearly two-thirds of
the world’s reactor-produced medical isotopes which are
used in over 34,000 nuclear medicine procedures
throughout the world every day.
© MDS Nordion
Treatment
Radiation is used to treat disease,
notably cancer, in several ways.
Therapy machines using the radioisotope
cobalt-60 deliver an external
beam of radiation to the cancer.
Today, there are some 1200 cobalt
machines operating throughout the
world and over 40,000 treatments a
day are delivered using this Canadian
technology. Cobalt-60 teletherapy
was first used at the Victoria Hospital
in London, Ontario in October 1951
using a machine designed by the
predecessor of MDS Nordion.
In other forms of treatments, radiation
sources can be inserted directly
into or beside tumours to kill cancer
cells. Known as brachytherapy, this
technique is more suited to certain
areas of the body, such as the
prostate, cervix and throat.
Exciting applications in isotope technology
are making new treatments
possible, such as treating liver cancer,
non-Hodgkin’s lymphoma and
brain cancer. In this form of treatment
radioisotopes are attached to
antibodies or other substances that
seek out cancer cells. Once connected
to the cells, they are acted upon
by the radiation from the attached
isotope thus delivering highly targeted
radiation to the tumour from within
the body.
http://www.cna.ca/english/nuclear%20facts/16-Nuclear%20Facts-health%20benefits.pdf
What are the benefits of nuclear medicine?
Nuclear medicine is a safe, painless, and cost-effective way of gathering information that may
otherwise be unavailable or require a more expensive and risky diagnostic test. One 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 tests. This early detection allows a disease to be
treated early in its course when there may be a better 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 any bony pain from certain types of cancer.
Risks

Because the doses of radiopharmaceutical administered are very small,
nuclear medicine procedures result in exposure to a small dose of radiation.
Nuclear medicine has been used for more than five decades, and there are
no known long-term adverse effects from such low-dose studies.

As with all radiologic procedures, be sure to inform your physician if you are
pregnant. In general, exposure to radiation during pregnancy should be kept
to a minimum.

Allergic reactions to the radiopharmaceutical can occur, but are extremely
rare.
http://www.radiologyinfo.org/content/gen_nuclear_med.htm
http://nuclearmedicine.stanford.edu/nm_benefits.html
What are the limitations of General Nuclear Medicine?
Nuclear medicine procedures are time-consuming. They involve administration of a
radiopharmaceutical, obtaining images, and interpreting the results. It can take hours to
days for the radiopharmaceutical to accumulate in the part of the body under study.
Imaging can take up to three hours to perform, though new equipment is available that
can substantially shorten the procedure time.
The radioactive materials used in Nuclear Medicine have very short half-lives,
which means that they decay rapidly into a harmless material. Often, the
injected radioactive material is only inside the body for a very short time,
and the total dose of radiation is small -similar, and sometimes even less
than, many other kinds of X-ray procedures. About twelve million nuclear
medicine exams are performed every year in the United States.
http://bidmc.harvard.edu/display.asp?leaf_id=5926
Radiology Safety Concerns
Radiation exposure can be frightening to some people. However, several
points should be kept in mind when considering the risk associated with any
radiation exposure.
First of all, we are all continuously exposed to radiation of many kinds,
including "ionizing radiation," the type of radiation found in X-ray studies and
nuclear medicine exams. Other types of radiation include "infrared" (felt as
heat), "ultraviolet" (gives us a tan and hastens the aging process of the skin),
and even visible light (allows us to see our environment).
The ionizing radiation we are exposed to comes from the sun, from natural
elements in the earth, from the materials used to build our homes, and even
from natural radioactive elements in our bodies. Depending upon the region
of the world in which we live, we are exposed each year to varying amounts
of radiation. In the Boston area, the annual radiation dose is approximately
300 millirads. If you lived in Denver, Colorado, the annual dose would be
approximately 600 millirads (mr). Some places in the world have annual
doses of over 1,000 mr. Interestingly enough, the places in the world with
the higher radiation doses also have lower cancer rates than those with lower
annual doses. This suggests that the cancer rate is not noticably affected by
low-dose radiation exposure, and the difference in cancer rate noted is
probably related to other variables in the environment, such as exposure to
cigarette smoke, automobile exhaust, and carcinogenic chemicals in the
environment.
A second point to keep in mind when considering the radiation dose from
your medical imaging test is that some radiologic procedures, such as
magnetic resonance imaging (MRI) and ultrasound, do not even use ionizing
radiation. Magnetic field and ultrasound energy, in the doses used by those
tests, have not been shown to cause significant tissue damage.
In tests that do use ionizing radiation, the dose is usually very small, and is
often similar to what you would get from natural background radiation in
everyday life. As an example, a dose for a typical X-ray procedure might be
30 - 1,000 mr. Other radiologic tests use higher radiation doses, as much as
5,000 millirads or more. Despite extensive study of the effects of radiation,
direct evidence does not show that these doses are harmful to humans.
Some experts believe that doses of radiation this small pose absolutely no
risk.
Examples of Radiation Exposure
(numbers are approximate)
Amount in
Millirads
Source of Exposure
Natural background exposures (from earth,
cosmic rays, etc.)
Boston,
Massachusetts
300 mr per year
Denver, Colorado
600 mr per year
Kerala, India
1,500 mr per year
Flying across the country
6 mr each way
Living next to a typical nuclear power plant
1-2 mr per year
Watching color TV
2-3 mr per year
Any potential risk of radiation exposure should be balanced against the
benefits derived from the exposure. Just as we might accept the risk of riding
a bicycle to obtain the benefits of exercise, we should consider that the small
risk that may be associated with radiation exposure can be well worth the
benefits obtained. For example, a mammogram can detect breast cancer long
before it can be felt during a physical exam. This early detection of the tumor
can save lives.
Some patients ask, "If the radiation risk is so small, why does the
technologist step behind a shield to prevent exposure to themself?" The
radiation dose for each exam is relatively small, but over time, the dose can
add up. There are many state and federal regulations limiting the total
radiation dose that may be received by people working with radiation. To
comply with those regulations, the technologist must follow strict precautions
to keep their cumulative exposure to a minimum.
Although no adverse health effects have been directly linked to low-dose
radiation exposure, the medical community is playing it safe with regards to
radiation. Most physicians are very careful about ordering radiologic tests.
They should not order a study unless it will improve patient care. If you have
a question about the importance or the necessity of a radiologic test that has
been ordered for you, be sure to ask your physician.
http://bidmc.harvard.edu/display.asp?leaf_id=5927