Radiation in Healthcare

Non-Ionizing and Ionizing Radiation

There are two kinds of radiation: non-ionizing radiation and ionizing radiation.

Non-Ionizing Radiation

Non-ionizing radiation has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons from atoms. Non-ionizing radiation can heat substances. Examples of non-ionizing radiation are radio waves, microwaves, infrared radiation, and the visible light spectrum.

We are exposed to low levels of non-ionizing radiation every day. Exposure to intense, direct amounts of non-ionizing radiation may result in damage to tissue due to heat.

Radiation treatment and x-rays are examples of ionizing radiation.
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Ionizing Radiation

Ionizing radiation has so much energy it can knock electrons out of atoms, a process known as ionization. Ionizing radiation can affect the atoms in living things, so it poses a health risk by damaging tissue and DNA in genes. Ionizing radiation comes from x-ray machines, cosmic particles from outer space, and radioactive elements. Radioactive elements emit ionizing radiation as their atoms undergo radioactive decay.

Radioactive decay is the emission of energy in the form of ionizing radiation. Ionizing radiation can be emitted in the form of alpha particles, beta particles, or gamma rays.

Types of Ionizing Radiation

Types of Radiation and Penetration

Alpha Particles

Alpha particles are positively charged and made up of two protons and two neutrons from the atom's nucleus. Alpha particles come from the decay of the heaviest radioactive elements, such as uranium, radium, and polonium. Even though alpha particles are very energetic, they are so heavy that they use up their energy over short distances and cannot travel very far from the atom.

The health effect from exposure to alpha particles depends significantly on how a person is exposed. Alpha particles lack the energy to penetrate even the outer layer of skin. Hence, exposure to the outside of the body is not a significant concern. Inside the body, however, they can be very harmful. If alpha-emitters are inhaled, swallowed, or get into the body through a cut, the alpha particles can damage sensitive living tissue. The way these large, heavy particles cause damage makes them more dangerous than other types of radiation. The ionizations they cause are very close together - they can release all their energy in a few cells leading to more severe damage to cells and DNA.

Beta Particles

Beta particles are small, fast-moving particles with a negative electrical charge emitted from an atom's nucleus during radioactive decay. These particles are emitted by unstable individual atoms such as hydrogen-3 (tritium), carbon-14, and strontium-90.

Beta particles are more penetrating than alpha particles. Still, they are less damaging to living tissue and DNA because the ionization they produce is more widely spaced. They also travel farther in the air than alpha particles. Still, they can be stopped by a layer of clothing or a thin layer of material, such as aluminum. Some beta particles can penetrate the skin and cause damage, such as skin burns. However, as with alpha-emitters, beta-emitters are most hazardous when they are inhaled or swallowed.

Gamma Rays

Gamma rays are weightless packets of energy called photons. Unlike alpha and beta particles, which have both energy and mass, gamma rays are pure energy. Gamma rays are like visible light but have much more energy. Gamma rays are often emitted along with alpha or beta particles during radioactive decay.

Gamma rays are a radiation hazard for the entire body. They can easily penetrate barriers that can stop alpha and beta particles, such as skin and clothing. Gamma rays have so much penetrating power that several inches of dense material, like lead, or a few feet of concrete, may be required to stop them. Gamma rays can pass entirely through the human body; as they pass through, they can cause ionizations that damage tissue and DNA.

X-Rays

Because of their use in medicine, almost everyone has heard of x-rays. X-rays are like gamma rays in that they are photons of pure energy. X-rays and gamma rays have the same basic properties but come from different parts of the atom. X-rays are emitted from processes outside the nucleus, but gamma rays originate inside the nucleus. They also are generally lower in energy and therefore less penetrating than gamma rays. X-rays can be produced naturally or by machines using electricity.

Thousands of x-ray machines are used daily in medical and dental procedures. Computerized tomography (CT or CAT scan) uses special x-ray equipment to make detailed bone and soft tissue images in the body. Medical x-rays are the single largest source of human-made radiation exposure.

Staff members can often be exposed to radiation from portable and fixed x-ray machines during diagnostic procedures. X-ray exposure can cause the following health issues:

X-ray exposure can cause many different health issues.

• Acute
• Erythema and dermatitis
• Large whole-body exposures cause nausea, vomiting, diarrhea, weakness, and death

• Chronic
• Skin cancer and bone marrow suppression
• Genetic effects may lead to congenital disabilities in the employee's offspring

Radiation exposure occurs when unprotected employees are near a machine in operation. The degree of exposure depends on the amount of radiation, duration of exposure, distance from the source, and the type of shielding in place.

Here are some possible solutions from OSHA when working with x-ray machines:

• Film Badge: Passive dosimeter for personal exposure monitoring should be worn whenever working with x-ray equipment, radioactive patients, or radioactive materials. Depending on the work situation, body badges may be worn at collar level, chest level, or waist level.
• Double-Badging: Personnel who work in high-dose fluoroscopy settings may be asked to wear two badges for additional monitoring.
• Ring badges: Used for measuring beta and gamma doses to the hand, they should be worn closest to the radiation source.

X-Ray Exposure Controls

Lead aprons should be worn if they are in the direct x-ray field.
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Other x-ray exposure controls include:

• X-ray rooms should have a barrier wall with a lead plated glass window. This way, technicians can step behind the barrier wall to take the x-ray and avoid radiation exposure.
• Lead plated glass is also used as a barrier to protect against radiation exposure when procedures must be done close to the patient.
• Lead strips provide some protection from radiation exposure for employees running fluoroscopy procedures.
• Lead aprons and lead gloves offer some protection for employees and patients and should be worn in the direct x-ray field. Opaque goggles are to be worn in the direct x-ray field.
• Some procedures like those that use remote fluoroscopy can be run from controls in an adjacent room, free from radiation exposure.
• A specific person should have the responsibility for assuring proper maintenance of the portable x-ray machines.
• Kits containing radioactive isotopes or specimens and excreta of humans and animals who have received radio nucleotides may pose a hazard. Exposure may also result from the handling of radioactive spills [29 CFR 1910.1096, Ionizing Radiation Standard].
• There should be a separate storage area for radioactive sources. This area should be adequately shielded.
• Document and retain inventories of radioactive materials. Only authorized personnel should have access to storage areas.

Ionizing Radiation Standard

OSHA's Ionizing Radiation Standard [29 CFR 1910.1096] requires:

Each radiation area shall be conspicuously posted with a sign or signs bearing the radiation caution symbol.

• Every employer shall supply appropriate personnel monitoring equipment, such as film badges, pocket chambers, pocket dosimeters, or film rings, and shall require the use of such equipment [29 CFR 1910.1096(d)(2)].
• Employers shall maintain records of all employees' radiation exposure for whom personnel monitoring is required and advise each employee of their exposure yearly.
• At the request of a former employee, an employer shall furnish the employee a report of the employee's exposure to radiation records 29 CFR 1910.1096(o)(1).
• Such a report shall be furnished within 30 days from the time the request is made.
• The report shall also include the results of any calculations and analysis of radioactive material deposited in the employee's body.
• The report shall be in writing and contain the following statement: "You should preserve this report for future reference."

• Each radiation area shall be conspicuously posted with a sign or signs bearing the radiation caution symbol with the wording "Caution Radiation Area" [29 CFR 1910.1096(e)(2)].

Radiation Detection

A variety of handheld and laboratory instruments are available for detecting and measuring radiation.
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Human senses cannot detect radiation. A variety of handheld and laboratory instruments are available for detecting and measuring radiation. The most common handheld or portable instruments are:

1. Geiger Counter, with Geiger-Mueller (G-M) Tube or Probe: A G-M tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when radiation interacts with the wall or gas in the tube. These pulses are converted and displayed on the instrument meter. These probes are most often used with handheld radiation survey instruments for contamination measurements.
2. MicroR Meter, with Sodium Iodide Detector: A solid crystal of sodium iodide creates a pulse of light when radiation interacts with it. This light pulse is converted to an electrical signal by a photomultiplier tube (PMT), which reads on the instrument meter. The pulse of light is proportional to the amount of light and the energy deposited in the crystal. If the instrument has a speaker, the pulses also give an audible click, a useful feature when looking for a lost source. Sodium iodide detectors can be used with handheld instruments or large stationary radiation monitors.
3. Portable Multichannel Analyzer: A sodium iodide crystal and PMT described above, coupled with a small multichannel analyzer (MCA) electronics package, are becoming much more affordable and common. When gamma-ray data libraries and automatic gamma-ray energy identification procedures are employed, these handheld instruments can automatically identify and display the type of radioactive materials present. When dealing with unknown sources of radiation, this is a handy feature.
4. Ionization (Ion) Chamber: This is an air-filled chamber with an electrically conductive inner wall and central anode and a relatively low applied voltage. When primary ion pairs are formed in the air volume from x-ray or gamma radiation interactions in the chamber wall, the central anode collects the electrons. A small current is generated and measured by an electrometer circuit and displayed digitally or on an analog meter.
5. Neutron REM Meter, with Proportional Counter: A proportional counter tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when neutron radiation interacts with the gas in the tube. These charged particles can then cause ionization in the gas, collected as an electrical pulse, like the G-M tube.

Contamination vs. Exposure

Radioactive contamination and radiation exposure can occur if radioactive materials are released into the environment.

Radioactive contamination and radiation exposure could occur if radioactive materials are released into the environment due to an accident, an event in nature, or an act of terrorism. Such a release could expose people and contaminate their surroundings and personal property.

Internal Contamination

Internal contamination occurs when people swallow or breathe in radioactive materials or when radioactive materials enter the body through an open wound or are absorbed through the skin. Some types of radioactive materials stay in the body and are deposited in different body organs. Other types are eliminated from the body in blood, sweat, urine, and feces.

External Contamination

External contamination occurs when radioactive material, in the form of dust, powder, or liquid, encounters a person's skin, hair, or clothing. In other words, the contact is external to a person's body. People who are externally contaminated can become internally contaminated if radioactive material gets into their bodies.

Radiation Exposure

Radioactive materials give off a form of energy that travels in waves or particles. This energy is called radiation. When a person is exposed to radiation, the energy penetrates the body. For example, when a person has an x-ray, he or she is exposed to radiation.

Radiation Emergencies

Emergency services physicians and nurses will be among the first clinicians to see and treat radiation emergency victims. Clinicians of all specialties will be responsible for providing care and information to:

• patients admitted to the hospital
• patients presenting for follow-up care
• concerned individuals
• others with questions about health effects related to the emergency

PPE In Radiation Emergencies

External Radiation Contamination

In a radiation emergency, the choice of appropriate personal protective equipment (PPE) depends on:

• response role and specific tasks
• risk of contamination

PPE can protect against the following:

• external contamination
• External contamination occurs when radioactive material, in the form of dust, powder, or liquid, comes into contact with a person's skin, hair, or clothing. (Click the image to the right to view animation.)

• internal contamination
• Internal contamination occurs when people swallow or breathe in radioactive materials, or when radioactive materials enter the body through an open wound or are absorbed through the skin. (Click the image to the right to view animation.)

Internal Radiation Contamination

• other physical hazards (i.e., debris, fire/heat, or chemicals)

PPE cannot protect against high energy exposure, highly penetrating forms of ionizing radiation associated with most radiation emergencies.

Lead aprons worn in diagnostic radiology do not provide sufficient shielding against these kinds of radiation.

PPE should include a personal radiation dosimeter whenever there is concern about exposure to penetrating ionizing radiation.

• Direct-reading personal radiation dosimeters may be used to monitor radiation dose. They can help workers stay within recommended Dose Limits for Emergency Workers.
• Direct-reading dosimeters should be worn so that a worker can easily see the read-out and, if equipped, hear warning alarms.

Recommended respiratory PPE includes a full-facepiece air-purifying respirator with a P-100 or High-Efficiency Particulate Air (HEPA) filter.

Other respiratory protective equipment (e.g., a simple surgical facemask, N-95 respirators), non-fit tested respirators, or ad hoc respiratory protection do not deliver appropriate or sufficient respiratory protection.

Environmental testing and hazard assessment by a safety professional can help identify hazards and risk levels and direct permissible PPE choices.

Short-Term Health Effects of Radiation Exposure

If you are injured after radiation exposure, seek medical attention right away. These injuries could be at high risk for infection and other long-lasting health effects.

Radioactive contamination and radiation exposure could occur if radioactive materials are released into the environment due to an accident, an event in nature, or an act of terrorism. Such a release could expose people and contaminate their surroundings and personal property.

Acute Radiation Syndrome (ARS)

People exposed to radiation will get ARS only if:

• The radiation dose was high.
• The radiation was able to reach internal organs (penetrating).
• The person's entire body, or most of it, received the dose.
• The radiation was received in a short time, usually within minutes.

Symptoms of ARS

Symptoms of ARS may include nausea, vomiting, headache, and diarrhea. These symptoms start within minutes to days after the exposure, last for minutes up to several days, and may come and go. If you have these symptoms after a radiation emergency, seek medical attention as soon as emergency officials determine it is safe to do so. After the initial symptoms, a person usually looks and feels healthy for a while. He or she will become sick again with variable symptoms and severity that vary depending on the radiation dose that he or she received. This seriously ill stage may last from a few hours up to several months. Click the button to view these symptoms.

Symptoms of acute radiation exposure may include nausea, vomiting, headache, and diarrhea.

Treatment of ARS

Treatment of ARS focuses on reducing and treating infections, maintaining hydration, and treating injuries and burns. Some patients may benefit from treatments that help the bone marrow recover its function. The lower the radiation dose, the more likely it is that the person will recover from ARS. In most cases, the cause of death is the destruction of the person's bone marrow, which results in infections and internal bleeding. For survivors of ARS, the recovery process may last from several weeks up to 2 years.

People with ARS typically also have some skin damage. There also can be hair loss. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later. Complete healing of the skin may take several weeks up to a few years, depending on the radiation dose the person's skin received.

Cutaneous Radiation Injury (CRI)

Cutaneous Radiation Injury (CRI) happens when exposure to a large dose of radiation causes injury to the skin. A doctor will suspect the presence of a CRI when a skin burn develops on a person who was not exposed to a source of heat, electrical current, or chemicals.

People may experience a Cutaneous Radiation Injury (CRI) when:

• They are exposed to certain types of radioactive materials that give off beta particles or penetrating gamma radiation or low-energy x-rays.

Symptoms of CRI

Symptoms of cutaneous radiation injury can appear from a few hours to several days after exposure.

Symptoms of CRI can appear from a few hours to several days after exposure. The early signs and symptoms of CRI include:

• itchiness
• tingling
• skin redness (erythema)
• swelling caused by a buildup of fluid (edema)

Over time, other symptoms may develop depending on the injury's site and the level of radiation dose to which the skin was exposed.

Treatment of CRI

After a radiation emergency, if you experience the above symptoms, seek medical attention as soon as emergency officials say it is safe to do so. If you cannot get medical attention quickly, gently rinse the area with water. Keep the site clean, dry, and covered until a doctor can provide additional treatment.

Long-Term Health Effects

People who receive high doses of radiation could have long-term effects.

Cancer

People who receive high doses of radiation could have a greater risk of developing cancer later in life, depending on the level of radiation exposure.

If employee exposures exceed either the PEL (Permissible Exposure Limits) or the excursion limit, employers must take the following actions:

Prenatal Radiation Exposure

Pregnant women must follow instructions from emergency officials and seek medical attention as soon as emergency officials say it is safe to do so after a radiation emergency.

Mental Health

Any emergency, including those involving radiation, can cause emotional and psychological distress.

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