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Learning Scope #369
1 contact hour
Expires Oct. 3, 2013
You can earn 1 contact hour of continuing education credit in three ways: 1) For immediate results and certificate; take the test online; grade and certificate are available immediately after taking the test. 2) Mail your completed exam (or a photocopy) along with the $8 fee (check or credit card) to ADVANCE for Nurses, Learning Scope, 2900 Horizon Dr., King of Prussia, PA 19406. 3) Fax the completed exam to 610-278-1426. If faxing or mailing, allow 30 days to receive certificate or notice of failure. A certificate of credit will be awarded to participants who achieve a passing grade of 70 percent or better.
Merion Matters, Inc. is an approved provider of continuing nursing education by the Pennsylvania State Nurses Association (No. 221-3-O-09), an accredited approver by the American Nurses Credentialing Center's Commission on Accreditation. Merion Matters Inc. is also approved as a provider by the California Board of Registered Nursing (No. 13230) and by the Florida Board of Nursing (No. 3298).
The goal of this CE is to provide nurses with current information on radiation safety they can apply to their practice. After reading this article, you will be able to:
1. Define the difference between non-ionizing and ionizing radiation.
2. Understand the basic principles of radiation protection.
3. Discuss the care and safety of patients receiving specialized radiotherapy treatments and the role of the nurse.
The Japanese nuclear crisis following the earthquake and tsunami in March 2011 brought to mind past nuclear accidents and the fear they evoked in the general public. The ensuing media attention to the health effects of radiation exposure, risk of developing cancer and our knowledge to date has sparked debate in the scientific community.
Much of our insight regarding acute exposure to radiation and its subsequent side effects comes from decades of follow-up of survivors of the atomic bombings in Hiroshima and Nagasaki in 1945. The nuclear power plant accident at Three Mile Island in 1979 was the most serious in U.S. history, even though there were no deaths or injuries to plant workers or people in the community. The impact of this accident caused the U.S. Nuclear Regulatory Commission to increase its oversight, resulting in changes in the nuclear power industry and permanent changes in how the Nuclear Regulatory Commission regulates its licensees. This in turn has reduced the risk to public health and safety.
In 1986, the Chernobyl nuclear power plant accident initially caused many severe radiation effects resulting in acute radiation sickness, higher than normal radiation exposure and even death of some of the workers. The incidence of radiation exposure from such accidents is rare, yet widespread fear of radiation often prevails.
In addition to our environment, nurses are at risk of occupational exposures by virtue of their occupation. What about radiation safety? What are the risks of radiation exposure and how can we reduce those risks? By increasing our awareness of radiation and the basic principles of radiation protection, we can take an active role in managing our own safety and those of our patients.
Radiation Sources & Types
Radiation is a natural part of our environment and our lives. There are three main sources of background radiation:
1. Radiation from space (cosmic) penetrates the atmosphere.
2. Radiation is part of the earth, with radon the largest source, accounting for approximately 55 percent of exposure.
3. People also have radioactive isotopes inside their bodies from birth.
Radiation is also man-made, and is used in industry and medicine. Radiation occurs when atoms release energetic particles or waves as they change into more stable forms.
Radiation has a wide range of energies, with two major divisions. Non-ionizing radiation does not have enough energy to remove electrons from atoms. Examples of this type of radiation are radio waves, visible light and microwaves.
Ionizing radiation has enough energy to remove electrons from atoms, which creates ions, and is used in electric power generation, manufacturing and medicine. Ionizing radiation is capable of damaging living cells by altering DNA.
There are four basic forms of ionizing radiation emitted from the nucleus of an atom:
1. Alpha particles are easily stopped by a sheet of paper or the skin, and move through the air a few inches. Alpha particles will cause internal damage if they are ingested or inhaled.
2. Beta particles can travel up to 10 feet in air, and can be stopped by thin shielding.
3. Gamma radiation is a type of electromagnetic wave that travels at the speed of light. It takes a thick shield of steel, lead or concrete to stop the rays. Neutrons are found in the nucleus of the atom and when bound remain stable. Free neutrons are produced by the processes of fission or fusion. They also are formed when cosmic rays interact with material in the environment, and make up a small amount of environmental radiation.
4. Ionizing radiation also includes X-rays, which are electromagnetic waves or photons not emitted from the nucleus, but emitted by energy changes in electrons.
Man-made radiation sources result in exposure to members of the public and occupationally exposed individuals. The most significant exposure to the public occurs from medical procedures such as diagnostic X-rays, nuclear medicine scans and radiation therapy. Some of the commonly used isotopes include I-131, Tc-99m, Co-60, Ir-192 and Cs-137. Examples of other sources include tobacco (0.35 millirem per cigarette), televisions, smoke detectors, airport X-ray systems, combustible fuels, and building and road construction materials. Additional sources of exposure involve shipment of radioactive materials and residual fallout from nuclear weapons testing and accidents.
Units of Measurement
Radiation is quantified by using various units. Roentgen is a unit used to measure a quantity called exposure; an amount of gamma and X-rays in the air. Rad (radiation absorbed dose) relates to absorbed dose in human tissue. Rem (roentgen equivalent man) refers to the ability of the specific type of radiation to damage biological tissue. In the U.S., doses are most commonly reported by the millirem (mrem). A millirem is one thousandth of a rem.
International units (SI) also are used throughout the world in health physics. Gray (Gy) is a unit used to measure a quantity called absorbed dose in some material. Absorbed dose is often expressed in terms of a gray or centigray. One gray is equivalent to 100 rads. Sievert (Sv) relates to absorbed dose in human tissue.
Radiation in Medicine
Radiation in medicine is the largest source of man-made radiation exposure. The majority is from diagnostic X-rays, which are used in more than half of all medical diagnoses. In the field of nuclear medicine, radioactive-labeled compounds (radiopharmaceuticals or radiotracers) are used to support diagnosis - for example, bone scans or PET scans. A PET scan uses a radioactive material (fluorine-18) tagged to a natural chemical (glucose) that is injected into the body, accumulates in an organ or tissue, and gives off energy in the form of gamma rays, which is then detected by gamma camera.
Radiation therapy is a treatment used in approximately 60 percent of cancer therapies. Targeted radiation destroys cancer cells and limits damage to surrounding healthy cells. Radiation is given with teletherapy (external beam radiation), with X-ray energy (photons), or with particle therapy. Particle therapy is a form of external beam radiation using beams of energetic protons, neutrons or positive ion, which are aimed at the target tumor.
In nuclear medicine, radiopharmaceuticals can be used to treat tumors. For example radioactive iodine (iodine-131) will concentrate in thyroid tissue and is used to treat thyroid cancer. Brachytherapy is a form of radiation therapy where a radiation source is placed inside or next to the area to be treated and can be low dose rate (LDR) or high dose rate (HDR).
LDR brachytherapy involves sources emitting radiation at a rate of up to 2 Gy/hour, with the source remaining in the patient for a number of hours or days. Placement of permanent brachytherapy seeds is a common treatment for prostate cancer. These LDR seeds, usually iodine-125, are permanently implanted within the prostate and gradually decay.
HDR brachytherapy involves a source, usually iridium-192, which emits radiation at a rate that exceeds 12 Gy per hour. The source is in the patient for a number of minutes and then removed. During this time, the patient is in a lead-lined room so there is no risk of exposure to staff. Brachytherapy allows a high dose to be delivered to a small area. Examples of tumors treated with brachytherapy include cancers of the cervix and female reproductive tract, prostate, breast, brain, skin, head and neck, trachea and bronchi, digestive tract, urinary tract and soft tissues.
Risks of Exposure
The Linear No-Threshold theory suggests that any exposure to radiation has some risk. However, exposure at very low levels has not shown a definitive risk. High doses of radiation are known to cause cancer in humans. Other adverse effects are genetic defects in the children of exposed parents or mental retardation in children of mothers exposed during pregnancy.
In general, the higher dose of radiation a person receives, the greater the risk of developing cancer. Radiation-induced cancers do not appear until 2-10 years after exposure. The risk from exposure varies among individuals. It is estimated the entire dose of natural background radiation over a lifetime would cause cancer in 1 in 100 people. For patients undergoing radiation therapy, the benefit should outweigh the risk associated with the exposure.
Acute side effects (during treatment) and late side effects (weeks to months after treatment) vary according to the dose, number of treatments (fractions) and the area being treated. The goal of radiation is to target and deliver a prescribed dose to a specific area of the body while restricting the dose to the surrounding healthy tissue and organs to less than or equal to normal tissue tolerance.
Applying ALARA Concept
Three basic concepts apply to all types of ionizing radiation and can affect a person's exposure. To keep exposure to radiation As Low As Reasonably Achievable (ALARA), one must apply the concepts of time, distance and shielding. The amount of radiation exposure is dependent upon the amount of time a person spends near the source of radiation; therefore, keep the time you spend near sources of radiation as short as possible. If radiation gets inside your body, you have to wait until it decays or your body eliminates it. A committed dose is one that accounts for continuing exposure over time or the exposure received from radioactive material that enters and stays in the body for many years.
The farther away a person is from a radiation source, the less their exposure. Therefore, increase your distance from the source as much as possible. Distance is important when dealing with gamma rays, as they can travel a longer distance due to their higher energy. If you double the distance, you reduce the exposure by a factor of four, whereas, halving the distance increases the exposure by a factor of four. If you think of a light bulb (source of radiation) in the middle of a circle that gives off energy equally in every direction, and if you double the radius and the radiation is spread out over four times as much area, the dose is only one-fourth as much.
The greater the shielding around a radiation source, the smaller the exposure. Therefore, use any appropriate shielding to protect yourself from exposure such as a lead bed shield or lead apron. Shielding means having something that will absorb radiation between you and the source of the radiation (not another person). The amount of shielding required depends on the amount of energy. For example, a piece of paper provides adequate shielding for alpha rays as they can't penetrate through it. Lead is necessary to provide adequate shielding for gamma rays due to their higher energy.
Specialized radiotherapy treatments require specific nursing considerations and patient education to ensure radiation safety. For example, iodine-125 is a low-energy radioactive material used in prostate cancer treatment with permanent seed implant. These seeds, similar to grains of rice, are deposited within the prostate gland, where the radiation remains for the most part and loses power over time (300 days or 10 months until no radioactivity is left in them).
Very little radiation leaves the body because it acts as a shield. Specific written instructions regarding precautions to protect the patient and others around them from unnecessary radiation (for 12 months) should be discussed and given to the patient before treatment. The radiation exposure at a distance of 2 feet is about the same amount a person would normally be exposed to in the environment. Children under 12 years old and pregnant women should avoid close contact (less than 3 feet) for an extended period of time for the first 2 months after the implant. There is no limit to the length of time children and pregnant women can be in the same room at a distance beyond 3 feet.
Following an implant, patients should be told their body wastes are not radioactive, they can have sex but should use condoms the first few times, avoid conceiving a child for at least 1 year, and that the seeds can set off a radiation detection device (carry wallet card with information). There is a slight chance one of the seeds may become dislodged and pass through the urine. Using tweezers to pick them up (never by hand), they should be flushed down the toilet. In the hospital setting, the seeds should be placed in a container filled with water and the radiation safety officer, doctor or physicist should be notified immediately. All urine, trash and linen need to be saved and checked by the physicist prior to disposal.
Iodine-131 is another radioactive material used for the ablation of residual thyroid tissue following surgery for thyroid cancer or for locally recurrent lesions or metastatic sites. I-131 is ingested and excreted in body fluids, mostly through the urine and, to a lesser extent, saliva. Patients should be encouraged to force fluids to flush out the radioactive material that is not treating the malignant thyroid tissue.
Each patient is identified by a special ID bracelet that includes their name, room number (if applicable), the isotope and the amount of activity. The majority of these patients are treated as outpatients and are given specific written and verbal instructions to follow for a set number of days depending on the dose they receive. These instructions are explicit and mainly include limiting time in public places, maintaining a distance of 6 feet when possible, avoiding prolonged contact with children and pregnant women (5 minutes), sleeping in separate beds, showering or bathing daily, keeping toiletries in a separate bag, washing hands and flushing the toilet twice after urinating, not sharing items that contact mouth or saliva (utensils, glasses), washing clothes separately, and not preparing or handling food.
If there are small children, a pregnant female in the household who cannot leave, or it is believed the patient cannot comply, the patient is hospitalized until his radiation exposure levels are low enough for him to return home. A letter is provided for patients in case they are traveling in the 3 months following treatment.
For hospitalized patients, nursing care should focus on reducing the patient's perception of isolation. Gloves and shoe covers are worn when entering the patient's room to prevent the spread of contamination. Disposable food trays, utensils and blood pressure cuffs are used. Nothing should leave the room, especially the patient. Special instructions are required for preventing contamination and handling of blood, vomit and urine.
Measures to avoid contamination of the patient's room, bathrom and the hospital area should be implemented. The radiation safety staff prepares the room and covers as many surfaces (floors) as possible to make decontamination easier. A pocket dosimeter is always worn by personnel when entering the restricted area. Pregnant nurses should never care for these patients. Instructions for these patients and their family should be obtained from the radiation safety officer.
Hospitals with a radiation department must have a committment to promoting the safe use of radiation-producing equipment and radioactive material as regulated by state and federal agencies. Routine radiation surveys, equipment compliance checks, radiation safety committee meetings, staff education (at time of orientation and then annually) and patients/visitors information related to radiation safety are all ways to promote a safe culture in the workplace.
The radiation safety officer ensures the institution complies with all state and federal regulations. All staff working around radiation are required to wear a radiation dosimetry badge that monitors cummulative exposure to ionizing radiation. If a woman declares a pregnancy, more frequent surveillance of exposure is needed. In the event of an emergency, all staff should follow the established procedures as per their institutional policies.
Nurses play an integral role in the treatment, care and safety of patients undergoing radiation therapy as do other members of the team (radiaiton oncologist, medical physicist, dosimetrist and therapist). Establishing and following patient safety procedures ultimately minimizes errors in radiation oncology.
Radiation is all around us and generally causes us no harm. As nurses, it is important to understand our risks from occupational radiation exposure and follow guidelines to reduce our exposure to ionizing radiation.
Assessing our own risk can be both objective (how a hazard can really affect us) and subjective (how we feel about it). Online risk assessment tools to calculate dose and risk are available to the public to assesss personal risks.
Increasing our understanding about radiation and following basic principles of radiation safety will help dispel myths, reduce fear, minimize errors and, above all, ensure our own safety and the safety of the patients entrusted in our care.
• CDC: www.cdc.gov
• Environmental Protection Agency: www.epa.gov
• Fox Chase Cancer Center: www.fccc.edu
• Health Physics Society: www.hps.org
• Nuclear Regulatory Agency: www.nrc.gov
To view the Course Outline and take the test online, click here.
For a printer-friendly version of the exam you can print out, complete and mail in to ADVANCE, click here.
Resources for this article can be accessed here.
Carole W. Sweeney and Jean Holland are clinical nurses in radiation oncology at Fox Chase Cancer Center, Philadelphia. They wish to acknowledge the following individuals for content editing assistance: Karen Sheehan, Bryan Edwards and Hope Harrell. The authors have completed disclosure forms and report no relationships relevant to the content of this article.