Radiation Safety and Infection Control

Radiation Safety

Radiation SafetyWilhelm 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

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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 AchievableTime 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

Air contaminated with infectious agents; other patients who have infectious diseases; visitors; contaminated food; contaminated instruments; hospital personnel

Environment

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.

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.

An environment in which the pathogenic microbes can live and multiply

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 portal from which to exit the reservoir

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.

A means of transmission

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.

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 portal of entry into a new host.

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