Transcript Radiation Safety and Infection Control

Radiation Safety and Infection
Control
Radiation Safety
Radiation Safety
Wilhelm Roentgen, Professor of Physics in Wurzburg, Bavaria, was
the first person to discover x-rays.
Roentgen was exploring the path of electrical rays passing through
a partially evacuated glass tube. Although the tube was covered in
black paper and the room was completely dark, he noticed that a
screen covered in fluorescent material was illuminated by the rays.
He later realized that a number of objects could be penetrated by
these rays, and that the projected image of his own hand showed a
contrast between the opaque bones and the translucent flesh. He
later used a photographic plate instead of a screen, and an image
was captured. In this way an extraordinary discovery had been
made: that the internal structures of the body could be made visible
without the necessity of surgery
Clarence Dally (1865-1904), assistant to industrialist
Thomas Alva Edison. The first recognized American X
ray fatality.
Soon after the discovery of X rays in 1895, both men
repeatedly exposed themselves to x rays in popular
demonstrations and investigations of the exotic new
imaging technology. Mr. Dally tested his X ray equipment
on his own hands.
X ray "burns" on his hands turned cancerous. The
cancer spread throughout his body and was ultimately
fatal
In spite of increasing use of infection
control measures and the control or
elimination of many diseases,
infections in patients while they are
receiving health care has increased
Ionizing radiation in excessive amounts or in amounts
higher than the accepted level in a brief time period can
result in either illness to the recipient or a potential genetic
disturbance to the descendants of the recipient.
Factors that can increase the risk of suffering the
adverse effects of ionizing radiation are:
• the patient's age at exposure
• sensitivity of exposed cells
•the size and area of the body exposed
The very young, the very old, and pregnant women are
the most vulnerable to adverse effects of radiation.
The goal of the radiographer must be to limit the amount
of ionizing radiation acceptable limits in the patient, others
in the vicinity, and personnel. To do this, the following
precautions must be taken:
• Maintain exposure to a level as low as reasonably
achievable (ALARA).
• Minimize the length of time the patient or others in the
vicinity are placed in the path of the x-ray beam.
• Maximize the distance between the source of the
ionizing radiation and the person exposed to it.
• Maximize the shielding from exposure of the patient
and others in the vicinity of the radiation.
ALARA – As Low As Reasonably Achievable
Time use the shortest exposure time possible. Remember that
radiation dosage increases with time.
Distance the closer a person is to the radiation beam, the
greater the exposure. The larger the field of radiation, the
greater the risks of scattering the ionizing radiation and the
greater the exposure risk. Increasing distance from the source
greatly reduces the exposure risk of the radiographer and
others in the vicinity.
Shielding Shielding persons who are unable to reduce their
exposure either by limiting time or increasing distance is the
third alternative for protection from ionizing radiation. Shielding
is done by setting up a protective barrier, usually lead or an
equivalent, between the source of the ionizing radiation and
the subject involved, whether the patient or others in the
vicinity
Use of gonadal shielding to protect male and female
reproductive organs (ovaries and testes) is of vital
importance. This is of particular importance when the patient
is a child or an adult of childbearing age. There are several
types of gonadal shields, including flat and molded contact
shields
The radiographer must use his or her technical
expertise to minimize patient exposure to radiation
The radiographer has the responsibility to understand
the technical aspects of the profession so that the
number of repeat radiographs necessary to achieve the
diagnostic purpose is minimized. The need to
frequently repeat exposures should be cause to put
critical thinking skills to work to assess and solve the
problems that are being encountered. Assess
communication with the patient as well as the skills
necessary to properly position the patient and set the
proper technical factors to achieve a diagnostic
radiograph on the first attempt.
Estimates of patient exposure to ionizing radiation must be made
available in the radiographic imaging department. These estimates
denote the amount of radiation an average patient undergoing a
given procedure would expect based on standard technique charts.
The amount of exposure actually received is less than compared
with these estimates
All radiographic imaging equipment must also be inspected for
radiation safety at regularly scheduled times.
Lead aprons and other protective apparel must be inspected
periodically for quality control purposes. This apparel must be
hung carefully over a wide bar or on special hangers when not
in use. To fold or drop them may jeopardize their integrity.
The radiographer and any health care worker who works in
constant contact with ionizing radiation must be monitored to
assess the amount of exposure to it. This may be done by
wearing a radiation-monitoring badge sensitive to low radiation
doses. A specialized company processes the badge on a
monthly or quarterly basis. The results are then returned to the
institution and must be made available to all occupational
persons who wear the badge.
Special precautions must be taken to prevent exposing pregnant
patients and pregnant health care workers to ionizing radiation.
This is particularly true during the early weeks of pregnancy, when
particular fetal tissues are especially sensitive to radiation.
This is why it is critical to ask the female patient if there is any
possibility of her being pregnant and also when her last
menstrual period was.
Pregnant workers who “declare” themselves to be pregnant are
double badged, and rotations in the department are varied so as to
limit the amount of exposure to radiation.
To minimize radiation exposure, the radiographer should not hold
the patient during a procedure on a routine basis. Sand bags and
positioning sponges should be used if possible. If this is not
feasible, then a relative or a person who is not working regularly in
radiography should be requested to assist
Infection Control
In spite of increasing use of infection control
measures and the control or elimination of
many diseases, infections in patients while they
are receiving health care has increased. This is
the result of increase of organisms becoming
resistant to antibiotics and the emergence of
new unrecognized diseases.
Infections acquired in the course of medical
care are called nosocomial infections
This term is most often applied to infections contracted
in an acute care hospital; however, it also applies to
infections patients receive while in extended care
facilities, outpatient clinics, and behavioral health
institutions. Infections contracted at birth by infants of
infected mothers are also classified as nosocomial.
A nosocomial infection that results from a particular treatment
or therapeutic procedure is called an iatrogenic infection.
Although a patient acquires a particular infection while in a
health care unit, he or she may not develop symptoms of the
illness until leaving the health care environment. This is still
considered to be a nosocomial infection.
A person who enters a health care facility with an infection
is said to have a community-acquired infection
Everyone has microorganisms in their bodies at all times.
These microorganisms are called normal flora. Infections
that are caused by microorganisms that are not normal
flora are called exogenous nosocomial infections.
When a person acquires an infection in the health
care setting as a result of an overgrowth of normal
flora, it is called an endogenous nosocomial infection.
Endogenous infections are often the result of the
alteration in the number of normal flora present in the
body or the alteration in placement of normal flora into
another body cavity. Endogenous infections may also
be the result of treatment with a broad-spectrum
antimicrobial drug that alters the number of normal
flora.
A variety of factors in the social and economic environment
may render a person more susceptible to acquiring a
nosocomial infection:
• Environment
• Therapeutic regimen
• Equipment
• Contamination during medical procedures
Environment
Air contaminated with infectious agents; other patients who
have infectious diseases; visitors; contaminated food;
contaminated instruments; hospital personnel
Therapeutic Regimen
Immunosuppressive and cytotoxic drugs used to treat
malignant or chronic diseases, which decrease the
patient's resistance to infection; antimicrobial therapy,
which may alter the normal flora of the body and
encourage growth of resistant strains of microbes
sometimes called hospital bacteria
Equipment
Instruments such as catheters, intravenous tubing,
cannulas, respiratory therapy equipment, and
gastrointestinal tubes that have not been adequately
cleaned and sterilized
Contamination during procedures
Microbes transmitted during dressing changes, catheter
insertion, or any invasive procedure may introduce
infective organisms if correct technique is not used.
Factors for susceptibility
•
•
•
•
•
•
•
•
Age
Heredity
Nutritional status
Stress
Inadequate rest and exercise
Personal habits
Health history
Inadequate defenses
Age
The very young have immature immune systems and
are more susceptible to nosocomial infections. Also,
as one ages, the immune system becomes less
efficient and organ function declines, making
infections more difficult to res
Heredity
Congenital and genetic factors passed on from birth
make individuals more or less resistant to disease
Nutritional status
Inadequate nutritional intake, obesity, or malnourishment as
a result of illness render one increasingly susceptible to
nosocomial infections
Inadequate rest and exercise
Efficient elimination and circulation decline as a
result of inadequate rest or exercise.
Personal habits
Smoking, excessive use of drugs and alcohol,
and/or dangerous sexual practices contribute to
lowering the body's defenses against
nosocomial infections
Health history
Persons with a history of poor health such as diabetes,
heart disease, or chronic lung disease, or children who
have not been immunized against diseases of childhood
are at increased risk for acquiring a nosocomial infection
Inadequate defenses
Broken skin; burns or trauma; or immunocompromised
persons related to a medical regimen are at increased risk
of acquiring a nosocomial infection
Infectious diseases are caused by
microorganisms
•
•
•
•
•
•
Bacteria
Fungi
Protozoa
Helminths
Viruses
Prions
Bacteria are colorless, minute, one-celled organisms with a
typical nucleus. They contain both deoxyribonucleic acid
(DNA) and ribonucleic acid (RNA). DNA carries the
inherited characteristics of a cell, and RNA constructs cell
protein in response to the direction of DNA.
Bacteria are classified according to their shape, which may
be spherical (cocci), oblong (bacilli), spiral (spirilla), or
pleomorphic (lacking a definitive shape). Short rods are
called coccobacilli. They may also be classified according to
their divisional grouping as diplococci (groups of two),
streptococci (chains), or staphylococci (grapelike bunches)
Salmonella, cullulitis, cholera, tuberculosis gangrene
Fungi are cells that require an aerobic environment to live
and reproduce. Fungi exist in two forms—yeasts and
molds. Yeasts are one-celled forms of fungi that
reproduce by budding. Molds (also called mycelia) form
multicellular colonies and reproduce by spore formation.
Thrush candida albicans
Parasites are organisms that live on or in other
organisms at the expense of the host organ. Parasites
may be plant or animal, but animal parasites are those
that are pathogenic to humans. A large number of
parasites produce disease, and they are roughly
classified as protozoa and helminths (parasitic worms).
Protozoa: malaria and toxoplasmosis
Helminths: flatworms and roundworms
Viruses are minute microorganisms that cannot be
visualized under an ordinary microscope. They are the
smallest microorganisms known to produce disease in
humans
HIV, Hepatitis A, B, C, D, E
A prion is a protein that does not contain DNA or RNA. Like
microorganisms, there are a number of prions present in
brain cells that prevent neurologic diseases; however, they
may mutate and become an infectious disease. A mutant
prion may be present by genetic predisposition or may be
the result of infection. Acquiring an infectious prion is the
result of transmission from an infected animal or person. The
disease most often resulting from a mutant infectious prion is
Creutzfeldt-Jakob disease. This disease is transmitted to
humans by eating infected meat or meat products and is
known as mad cow disease.
Elements Needed to Transmit Infection
• An infectious agent and a reservoir of available
organisms
• An environment in which the pathogenic microbes can
live and multiply
• A portal of exit from the reservoir
• A means of transmission
• A portal of entry into a new host
An infectious agent and a reservoir of
available organisms
An infectious agent, which may be a bacterium, a fungus,
a virus, a prion, or a parasite. Infectious agents vary in
their ability to cause disease.
An environment in which the pathogenic
microbes can live and multiply
The reservoir can be a human being, an animal, a plant,
water, food, earth, or any combination of organic materials
that support the life of a particular pathogen. Infection is
prevented by removing the causative microbe from the
reservoir.
A portal from which to exit the reservoir
In the case of a human reservoir, the portals of exit
might be the nose, mouth, urinary tract, intestines, or
an open wound from which blood or purulent
exudate can escape. There can be more than one
portal of exit
..
A means of transmission
Infection is transmitted by direct or indirect contact, by
droplet, by vehicle, by vector, or by airborne route.
Contact is direct when a person or an animal with a
disease or his blood or body fluids are touched. This
contact can be by touching with the hands, by kissing,
by percutaneous injection, or by sexual intercourse. A
person who transmits disease-causing organisms but
has no apparent signs or symptoms of that disease is
called a carrier. Particular organisms require specific
routes of transmission for infection to occur.
Indirect contact is defined as the transfer of pathogenic
microbes by touching objects
(called fomites) that have been contaminated by an infected
person. These objects include dressings, instruments, clothing,
dishes, or anything containing live infectious microorganisms.
Droplet contact involves contact with infectious secretions
that come from the conjunctiva, nose, or mouth of a host or
disease carrier as the person coughs, sneezes, or talks.
Droplets can travel from approximately 3 to 5 feet and should
not be equated with the airborne route of transmission, which
is described later.
Vehicles may also transport infection. Vehicle route of
transmission includes food, water, drugs, or blood
contaminated with infectious microorganisms.
The airborne route of transmission indicates that residue
from evaporated droplets of diseased microorganisms are
suspended in air for long periods of time. This residue is
infectious if inhaled by a susceptible host.
Vectors are insect or animal carriers of disease. They deposit
the diseased microbes by stinging or biting the human host
.
A portal of entry into a new host.
Entry of pathogenic microorganisms into a new host
can be by ingestion, by inhalation, by injection, across
mucous membranes, or, in the case of a pregnant
woman, across the placenta
A human host can be any susceptible person. Persons
particularly susceptible to infection are those who are poorly
nourished or are fatigued. Those at greater risk are persons
with chronic diseases such as diabetes mellitus or cancer.
Immune-suppressed persons are at great risk of acquiring
infections. Previous infection with a particular disease or
vaccination against a particular disease can render an
individual immune to infection.
Socioeconomic status and culture also play a role in host
susceptibility. Persons living in poor environments are more
likely to contact some diseases owing to poor hygienic
conditions and the poor diets that they are forced to endure.
Some diseases have a strong hereditary aspect, which makes
them more likely to occur in particular races or families who
are genetic carriers of the disease.
Urinary tract infections are the most common,
followed by pneumonias, skin and soft tissue
infections, and invasive bloodstream infections.
Surgical wound infections account for 20 percent to
30 percent of cases, but contribute to as many as 57
percent of extra hospital days and 42 percent of
extra costs. Staphylococcus epidermidis, S. aureus,
Enterococcus faecium, Enterococcus faecalis, E.
coli, Enterobacter species, and P. aeruginosa are
common pathogens in wound infections