Archives for August 2011

Top Myths About X-ray Aprons

All x-ray aprons have lead in them.

Lead has been the industry standard for radiation protection, but other metals like tin and tungsten can attenuate radiation just as well, or better. These metals have been used to create radiation protection products without any use of lead even though the term lead equivalency, or LE, is used to gauge the amount of protection they provide. Not only is there other metals but PVCs as well. PVCs are mixed with the attenuating metals to give the apron flex and durability.

X-ray apron come in one style.

X-ray aprons come in a variety of styles, colors, and patterns. Depending on the application at hand you can find frontal, vest and skirt, or full wrap aprons.  A frontal apron might be something to consider if you find yourself performing quick procedures with no back exposure.

You can store an x-ray apron by folding it like a t-shirt.

Folding an x-ray apron can lead to internal cracking creating space for radiation to escape through. Make sure you always hang your x-ray protection on a hanger or lead apron rack. With proper care, an x-ray apron can last up to 10 years.

All x-rays require an apron for protection.

When x-ray machines were first invented patients required protection because there was limited control of the radiation beam and exposure time was long. Due to advances in radiation technology doctors are now able to restrict an x-ray beam to a target area and significantly limit the exposure time. Compared to a CT scan, a dental x-ray requires minimal radiation and protection is not always necessary. Dentists still equip their patients with an apron to give them a peace of mind.

The effectiveness of an x-ray apron is determined by thickness.

When determining the effectiveness of an x-ray apron, one must look at the attenuation rate of the material. Thickness can play a factor in attenuation, but different materials can absorb or deflect radiation in dissimilar ways. Remember all x-ray aprons are made up of a matrix of composites, so depending on the manufacturer, thickness can vary but attenuation may remain the same.

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Attenuation Of Radiation

Is your radiation shielding really protecting you? Sometimes we see situations where no protection is needed. Other times a full wrap apron is required.  So as a patient, doctor, or radiology technician how does one know if they are being properly protected?

Radiation on a Molecular Level

In order to understand radiation protection we would like to briefly educate you on the science of x-rays and why they can be dangerous. Exposure to different energies can affect the human body in various ways. When we are exposed to high levels of energy there can be negative side effects. For instance light rays can blind, sound waves can cause deafness, and heat waves can burn. Similarly, negative side effects may result from exposure to x-ray energy, but why? All matter is made up of atoms. When x-ray energy collides with atoms its effect depends on the strength of the ray and the type of atom encountered. When the interaction causes an atom to lose an electron, an ion, or electrically charged atom is formed. This is the negative effect of radiation exposure because electrically charged atoms are able to break DNA chains. Broken DNA either dies or mutates, which can lead to cancerous cells and birth defects.  Due to the fact that alteration of human cells is a possible outcome of radiation exposure, it is imperative to take all proper protective measures against overexposure.

Proper Protection

When referring to radiation protection, a common misunderstanding is the thicker the protective barrier, the better. Yet, this is not true. Yes, thickness plays a role in protection, but the attenuation factor is the main focus. Remember, attenuation is the measurement of absorbed and deflected energy as it passes through a material. (To understand the basics of attenuation read our “What is Attenuation” blog post.) Let’s equate the attenuation theory to a well known item: sunglasses. If you are picking out a pair of sunglasses to protect your eyes from sun damage, your main focus is the tint of the lens, not its thickness. Light is absorbed by dark colors, so the darker the tint of the lens, the less light will pass through to your eyes. Thousands of sunglasses offer the same lens thickness, but the attenuation of light varies most with the lens’ tint. The same concept applies to radiation protection. Just like different lens tints attenuate light rays, different materials attenuate radiation energy.

So what are effective radiation attenuating materials? The truth is that even air attenuates radiation to a degree, because every element attenuates radiation to some extent. Through research and development, it has been concluded that when it comes to radiation attenuation, the most effective elements are the metals. When this fact was discovered, lead was inexpensive and readily available, so lead aprons were put to use.  Lead quickly became the industry standard for radiation protection and the term lead equivalency evolved as the measuring tool used to gauge the effectiveness of radiation protection. Lead aprons are comprised of a matrix of lead and PVC (to give the lead durability).

 This matrix is then formed into sheets and layered for stronger attenuation and increased flex. So what is the downside? You likely already know it – Protective Apparel that only uses lead as the attenuating metal is HEAVY! Prolonged use can cause back and shoulder injuries for personnel required to wear the aprons day in and day out.  The radiation protection industry solved this problem by developing light weight and non lead aprons that protect just as well as the original lead aprons. Lightweight aprons utilize a combination of lead and non lead elements to achieve effective protection levels. Non Lead Aprons use only nonlead elements to achieve effective protection levels. Some of the nonlead elements found in the lightweight and lead free aprons on the market today are tin, bismuth, aluminum, barium, and titanium. These metals are able to attenuate x-rays efficiently while still meeting the original lead equivalency standard. Tin, a lighter weight metal, is combined with lead to create light weight aprons, which reduces stress on shoulders and the lower back. Nonlead aprons not only provide the lightest weight option, due to their lack of lead content, they are considered non-hazardous and can be safely disposed of without fear of environmental impact. The reason there has not been a strong push for adopting these lightweight and nonlead forms of protection is due to a misunderstanding of the attenuation process. Many medical imaging personnel believe lead is the only material that can attenuate radiation effectively.  Now that you know that many metals effectively attenuate radiation energy, you can make a better informed decision about the protective apparel you choose.

Prior to revealing the dangers of cell mutation, uncontrolled amounts of x-rays were being used for various purposes. In fact, in the 1920s you could walk into a shoe shop and take an x-ray of your foot inside a shoe to find a perfect fit! Shielding ourselves is not the only precaution we can take to protect ourselves from harmful x-ray exposure. Equipment manufacturers have developed x-ray machines with the ability to: control the direction of the radiation beam, limit exposure time, and adjust the power of radiation. The main goal in medical imaging today is to expose patients to the bare minimum amount of radiation and still obtain optimal results. You may hear the term ALARA which stands for As Low As Reasonably Achievable. An example of this would be x-raying a child as compared to an adult. Because a child is smaller there is less mass present for the x-ray to penetrate. So the imaging professional can lower the typical adult power level of the x-ray machine and still obtain optimal results.

Anyone working around radiation should ensure they are aware of the levels and frequency with which they are exposed.  Understanding exposure and your risk will ultimately allow you to select the proper protection apparel. The attenuation concept is a major focus in radiology and the more we understand about its nature, the further we can advance radiation practices with the correct equipment and protection. If you are ever administering or receiving an x-ray and you are concerned about radiation protection, have no fear if lead is nowhere near. The attenuation concept is still in play when other metals are used. Product manufacturers are meeting standards to protect you from unnecessary radiation damage while preventing shoulder and back injuries!

What Is Attenuation?

Attenuation Defined

Attenuation is the measurement of energy absorbed and deflected as it passes through a medium. In simpler terms, attenuation is how much stopping power a material has on energy. Consider how energy travels; most energy forms, whether sound, heat, light or radiation, travel in waves.  The wavelength and amount of force propelling the energy affects how that energy reacts to any object in its path.  The atoms of the object will absorb some energy, deflect some energy or allow some energy to flow through. The measurement of the absorbed and deflected energy provides us with an attenuation rate for any given material.

Deflected energy is energy that’s original course of travel has been changed by an object in its path.  Deflected energy is also known as scatter energy. An example of deflected energy is present in the following rescue scenario: In a survival situation, a mirror can be used to signal for help by deflecting the sun’s light rays toward a rescue plane.  The energy source is the sunlight and the object is the mirror. When the mirror is placed in the path of the light waves, the mirror’s atoms deflect the energy in various new directions.  This scatter energy can be seen by the search and rescue team when flying overhead.

Absorbed energy is energy that is incorporated into the atoms of an object in its path. A musician in a recording studio appreciates the concept of absorbed energy when considering their sound proof walls. In this scenario, sound waves are the energy and foam padding is the material. As the instrument’s sound waves travel toward the foam padded walls, the atomic composition of the foam absorbs the sound energy.  This effective energy absorption is particularly important as it provides superior sound quality.  Without absorption by the foam padding, the sound energy would be deflected and the scattered sound waves would cause an echo in the recording.

The term attenuation is often heard when referring to an x-ray. The same concepts described above apply to medical x-rays. Radiation is the energy source and the target of clinical interest is the object. Radiation is emitted through medical imaging equipment and the energy is attenuated by a patient’s bones and internal structures to create an image. The use of x-ray energy allows doctors to see inside a patient without having to create an incision. The medical industry’s understanding of the attenuation concept is invaluable to every patient that has relied on medical imaging to ensure their health and well being.

Attenuation is an important concept which must be understood in many applications. Without an understanding of attenuation one may not survive a life threatening situation, music downloads would not sound clear and broken bones would not be easy to diagnose.  The world constantly uses the knowledge of attenuation to develop various technologies in an effort to realize optimal results.  Even today we continue to mix and match materials and energy sources to advance technology through the use of the attenuation concept.