Radiation is energy that comes from a source and travels through space and may be able to penetrate various materials. Light, radio, and microwaves are types of radiation that are called nonionizing. The kind of radiation discussed in this document is called ionizing radiation because it can produce charged particles (ions) in matter.
Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because unstable atoms have an excess of energy or mass or both. Radiation can also be produced by high-voltage devices (e.g., x-ray machines).
Atoms with unstable nuclei are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation. The kinds of radiation are electromagnetic (like light) and particulate (i.e., mass given off with the energy of motion). Gamma radiation and x rays are examples of electromagnetic radiation. Gamma radiation originates in the nucleus while x rays come from the electronic part of the atom. Beta and alpha radiation are examples of particulate radiation.
Interestingly, there is a "background" of natural radiation everywhere in our environment. It comes from space (i.e., cosmic rays) and from naturally occurring radioactive materials contained in the earth and in living things.
Radiation Exposure from Various Sources
Source Exposure
External Background Radiation
60 mrem/yr, U.S. Average
Natural K-40 and Other Radioactivity in Body
40 mrem/yr
Air Travel Round Trip (NY-LA)
5 mrem
Chest X-Ray Effective Dose
10 mrem per film
Radon in the Home
200 mrem/yr (variable)
Man-Made (medical x rays, etc.)
60 mrem/yr (average)
Thursday, April 22, 2010
How many different types of Radiation are there?
The radiation one typically encounters is one of four types: alpha radiation, beta radiation, gamma radiation, and x radiation. Neutron radiation is also encountered in nuclear power plants and high-altitude flight and emitted from some industrial radioactive sources.
Alpha Radiation
Alpha radiation is a heavy, very short-range particle and is actually an ejected helium nucleus. Some characteristics of alpha radiation are:
o Most alpha radiation is not able to penetrate human skin.
o Alpha-emitting materials can be harmful to humans if the materials are inhaled, swallowed, or absorbed through open wounds.
o A variety of instruments has been designed to measure alpha radiation. Special training in the use of these instruments is essential for making accurate measurements.
o A thin-window Geiger-Mueller (GM) probe can detect the presence of alpha radiation.
o Instruments cannot detect alpha radiation through even a thin layer of water, dust, paper, or other material, because alpha radiation is not penetrating.
o Alpha radiation travels only a short distance (a few inches) in air, but is not an external hazard.
o Alpha radiation is not able to penetrate clothing.
Examples of some alpha emitters: radium, radon, uranium, thorium.
Beta Radiation
Beta radiation is a light, short-range particle and is actually an ejected electron. Some characteristics of beta radiation are:
o Beta radiation may travel several feet in air and is moderately penetrating.
o Beta radiation can penetrate human skin to the "germinal layer," where new skin cells are produced. If high levels of beta-emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury.
o Beta-emitting contaminants may be harmful if deposited internally.
o Most beta emitters can be detected with a survey instrument and a thin-window GM probe (e.g., "pancake" type). Some beta emitters, however, produce very low-energy, poorly penetrating radiation that may be difficult or impossible to detect. Examples of these difficult-to-detect beta emitters are hydrogen-3 (tritium), carbon-14, and sulfur-35.
o Clothing provides some protection against beta radiation.
Examples of some pure beta emitters: strontium-90, carbon-14, tritium, and sulfur-35.
Gamma and X Radiation
Gamma radiation and x rays are highly penetrating electromagnetic radiation. Some characteristics of these radiations are:
o Gamma radiation or x rays are able to travel many feet in air and many inches in human tissue. They readily penetrate most materials and are sometimes called "penetrating" radiation.
o X rays are like gamma rays. X rays, too, are penetrating radiation. Sealed radioactive sources and machines that emit gamma radiation and x rays respectively constitute mainly an external hazard to humans.
o Gamma radiation and x rays are electromagnetic radiation like visible light, radiowaves, and ultraviolet light. These electromagnetic radiations differ only in the amount of energy they have. Gamma rays and x rays are the most energetic of these.
o Dense materials are needed for shielding from gamma radiation. Clothing provides little shielding from penetrating radiation, but will prevent contamination of the skin by gamma-emitting radioactive materials.
o Gamma radiation is easily detected by survey meters with a sodium iodide detector probe.
o Gamma radiation and/or characteristic x rays frequently accompany the emission of alpha and beta radiation during radioactive decay.
Examples of some gamma emitters: iodine-131, cesium-137, cobalt-60, radium-226, and technetium-99m.
Alpha Radiation
Alpha radiation is a heavy, very short-range particle and is actually an ejected helium nucleus. Some characteristics of alpha radiation are:
o Most alpha radiation is not able to penetrate human skin.
o Alpha-emitting materials can be harmful to humans if the materials are inhaled, swallowed, or absorbed through open wounds.
o A variety of instruments has been designed to measure alpha radiation. Special training in the use of these instruments is essential for making accurate measurements.
o A thin-window Geiger-Mueller (GM) probe can detect the presence of alpha radiation.
o Instruments cannot detect alpha radiation through even a thin layer of water, dust, paper, or other material, because alpha radiation is not penetrating.
o Alpha radiation travels only a short distance (a few inches) in air, but is not an external hazard.
o Alpha radiation is not able to penetrate clothing.
Examples of some alpha emitters: radium, radon, uranium, thorium.
Beta Radiation
Beta radiation is a light, short-range particle and is actually an ejected electron. Some characteristics of beta radiation are:
o Beta radiation may travel several feet in air and is moderately penetrating.
o Beta radiation can penetrate human skin to the "germinal layer," where new skin cells are produced. If high levels of beta-emitting contaminants are allowed to remain on the skin for a prolonged period of time, they may cause skin injury.
o Beta-emitting contaminants may be harmful if deposited internally.
o Most beta emitters can be detected with a survey instrument and a thin-window GM probe (e.g., "pancake" type). Some beta emitters, however, produce very low-energy, poorly penetrating radiation that may be difficult or impossible to detect. Examples of these difficult-to-detect beta emitters are hydrogen-3 (tritium), carbon-14, and sulfur-35.
o Clothing provides some protection against beta radiation.
Examples of some pure beta emitters: strontium-90, carbon-14, tritium, and sulfur-35.
Gamma and X Radiation
Gamma radiation and x rays are highly penetrating electromagnetic radiation. Some characteristics of these radiations are:
o Gamma radiation or x rays are able to travel many feet in air and many inches in human tissue. They readily penetrate most materials and are sometimes called "penetrating" radiation.
o X rays are like gamma rays. X rays, too, are penetrating radiation. Sealed radioactive sources and machines that emit gamma radiation and x rays respectively constitute mainly an external hazard to humans.
o Gamma radiation and x rays are electromagnetic radiation like visible light, radiowaves, and ultraviolet light. These electromagnetic radiations differ only in the amount of energy they have. Gamma rays and x rays are the most energetic of these.
o Dense materials are needed for shielding from gamma radiation. Clothing provides little shielding from penetrating radiation, but will prevent contamination of the skin by gamma-emitting radioactive materials.
o Gamma radiation is easily detected by survey meters with a sodium iodide detector probe.
o Gamma radiation and/or characteristic x rays frequently accompany the emission of alpha and beta radiation during radioactive decay.
Examples of some gamma emitters: iodine-131, cesium-137, cobalt-60, radium-226, and technetium-99m.
Lead Garments
Have you ever had any of the following questions concerning Lead garments?
How long does a lead apron need to be? Does it need to cover the femurs? Does it need to be a wrap-around if I routinely have my back to the fluoroscopy table?
With regard to types of leaded aprons, I strongly recommend a wrap-around or coat-type apron to reduce exposures to the bone marrow in the vertebrae and critical organs in the trunk when your back is toward the fluoroscopy unit. A very good option is a combination vest and skirt apron, which wraps around the body and distributes the weight across the shoulders and hips. Nearly all the critical organs can be shielded by a lead apron that has a length to about mid-femur. The bone marrow not shielded by a standard leaded apron is in the skull, cervical vertebrae, and long bones of the arms and lower long bones of the legs.
Why is Lead Shielding Important?
The cancer risks from low-level, low-dose-rate radiation exposure are based on the doses to various radiosensitive critical organs. The major critical organs include the gonads, breast, active bone marrow, lungs, thyroid, bone surfaces, and, to a lesser degree, various other organs in the trunk of the body. Except for various regions of active bone marrow and the brain, these body parts have a small associated risk from radiation exposure,
If the chances of damage to reproductive organs from x-rays are so small, why do patients have to wear protective aprons?
Leaded aprons are used for diagnostic x-ray procedures to protect those portions of the body that are not involved in the image. The risk to the patient from diagnostic doses is very small and may even be zero. However, the apron is used in an application of the ALARA concept: the dose should be kept As Low As Reasonably Achievable. The apron is inexpensive and carries no discomfort or risk. Although it may be unnecessary for many very low-dose procedures such as chest or dental x rays, it is a prudent practice.
How long does a lead apron need to be? Does it need to cover the femurs? Does it need to be a wrap-around if I routinely have my back to the fluoroscopy table?
With regard to types of leaded aprons, I strongly recommend a wrap-around or coat-type apron to reduce exposures to the bone marrow in the vertebrae and critical organs in the trunk when your back is toward the fluoroscopy unit. A very good option is a combination vest and skirt apron, which wraps around the body and distributes the weight across the shoulders and hips. Nearly all the critical organs can be shielded by a lead apron that has a length to about mid-femur. The bone marrow not shielded by a standard leaded apron is in the skull, cervical vertebrae, and long bones of the arms and lower long bones of the legs.
Why is Lead Shielding Important?
The cancer risks from low-level, low-dose-rate radiation exposure are based on the doses to various radiosensitive critical organs. The major critical organs include the gonads, breast, active bone marrow, lungs, thyroid, bone surfaces, and, to a lesser degree, various other organs in the trunk of the body. Except for various regions of active bone marrow and the brain, these body parts have a small associated risk from radiation exposure,
If the chances of damage to reproductive organs from x-rays are so small, why do patients have to wear protective aprons?
Leaded aprons are used for diagnostic x-ray procedures to protect those portions of the body that are not involved in the image. The risk to the patient from diagnostic doses is very small and may even be zero. However, the apron is used in an application of the ALARA concept: the dose should be kept As Low As Reasonably Achievable. The apron is inexpensive and carries no discomfort or risk. Although it may be unnecessary for many very low-dose procedures such as chest or dental x rays, it is a prudent practice.
Is Anything We Use in Everyday Life Radioactive?
Everything we encounter in our daily lives contains some radioactive material, some naturally occurring and some man-made: the air we breathe, the water we drink, the food we eat, the ground we walk upon, and the consumer products we purchase and use. Although they might be familiar with the use of radiation to diagnose disease and treat cancer, many people, when they hear the terms "radioactive" and "radiation," tend to think of mushroom clouds and the monster mutants that inhabit the world of science fiction movies and comic books. Careful analyses can identify and quantify the radioactive material in just about anything. This document describes a few of the more commonly encountered and familiar consumer products that can contain sufficient radioactive material for it to be distinguished from background with a simple handheld radiation survey meter.
Smoke Detectors
Most residential smoke detectors contain a low-activity americium-241 source. Alpha particles emitted by the americium ionize the air, making the air conductive. Any smoke particles that enter the unit reduce the current and set off an alarm. Despite the fact that these devices save lives, the question "are smoke detectors safe?" is still asked by those with an inordinate fear of radiation. The answer, of course, is "yes, they are safe." Instructions for proper installation, handling, and disposal of smoke detectors are found on the package.
Watches and Clock
Modern watches and clocks sometimes use a small quantity of hydrogen-3 (tritium) or promethium-147 as a source of light. Older (for example, pre-1970) watches and clocks used radium-226 as a source of light. If these older timepieces are opened and the dial or hands handled, some of the radium could be picked up and possibly ingested. As such, caution should be exercised when handling these items
Ceramics
Ceramic materials (for example, tiles, pottery) often contain elevated levels of naturally occurring uranium, thorium, and/or potassium. In many cases, the activity is concentrated in the glaze. Unless there is a large quantity of the material, readings above background are unlikely. Nevertheless, some older (for example, pre-1960) tiles and pottery, especially those with an orange-red glaze (for example, Fiesta® ware) can be quite radioactive.
Glass
Glassware, especially antique glassware with a yellow or greenish color, can contain easily detectable quantities of uranium. Such uranium-containing glass is often referred to as canary or vaseline glass. In part, collectors like uranium glass for the attractive glow that is produced when the glass is exposed to a black light. Even ordinary glass can contain high-enough levels of potassium-40 or thorium-232 to be detectable with a survey instrument. Older camera lenses (1950s-1970s) often employed coatings of thorium-232 to alter the index of refraction.
Fertilizer
Commercial fertilizers are designed to provide varying levels of potassium, phosphorous, and nitrogen. Such fertilizers can be measurably radioactive for two reasons: potassium is naturally radioactive, and the phosphorous can be derived from phosphate ore that contains elevated levels of uranium.
Food
Food contains a variety of different types and amounts of naturally occurring radioactive materials. Although the relatively small quantities of food in the home contain too little radioactivity for the latter to be readily detectable, bulk shipments of food have been known to set off the alarms of radiation monitors at border crossings. One exception would be low-sodium salt substitutes that often contain enough potassium-40 to double the background count rate of a radiation detector.
Gas Lantern Mantles
While it is less common than it once was, some brands of gas lantern mantles incorporate thorium-232. In fact it is the heating of the thorium by the burning gas that is responsible for the emission of light. Such mantles are sufficiently radioactive that they are often used as a check source for radiation detectors.
Antique Radioactive Curative Claims
In the past, primarily 1920 through 1950, a wide range of radioactive products were sold as cure-alls, for example, radium-containing pills, pads, solutions, and devices designed to add radon to drinking water. The states generally have regulatory authority over these devices. In some cases, a state might even require that these devices be registered or licensed. Most such devices are relatively harmless but occasionally one can be encountered that contains potentially hazardous levels of radium. If there is any question about the safety of such devices, the public is strongly encouraged to contact the state radiation-control program for advice.
Information taken from a Health Physics Society Fact Sheet, "Consumer Products Containing Radioactive Materials," published in November 2002.
Additional Information
• National Council on Radiation Protection and Measurements, "Radiation Exposure of the US Population from Consumer Products and Miscellaneous Sources," NCRP Report No. 95, Bethesda, MD, 1987.
• US Nuclear Regulatory Commission, "Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials, NUREG-1717, Washington, DC, 2001.
Smoke Detectors
Most residential smoke detectors contain a low-activity americium-241 source. Alpha particles emitted by the americium ionize the air, making the air conductive. Any smoke particles that enter the unit reduce the current and set off an alarm. Despite the fact that these devices save lives, the question "are smoke detectors safe?" is still asked by those with an inordinate fear of radiation. The answer, of course, is "yes, they are safe." Instructions for proper installation, handling, and disposal of smoke detectors are found on the package.
Watches and Clock
Modern watches and clocks sometimes use a small quantity of hydrogen-3 (tritium) or promethium-147 as a source of light. Older (for example, pre-1970) watches and clocks used radium-226 as a source of light. If these older timepieces are opened and the dial or hands handled, some of the radium could be picked up and possibly ingested. As such, caution should be exercised when handling these items
Ceramics
Ceramic materials (for example, tiles, pottery) often contain elevated levels of naturally occurring uranium, thorium, and/or potassium. In many cases, the activity is concentrated in the glaze. Unless there is a large quantity of the material, readings above background are unlikely. Nevertheless, some older (for example, pre-1960) tiles and pottery, especially those with an orange-red glaze (for example, Fiesta® ware) can be quite radioactive.
Glass
Glassware, especially antique glassware with a yellow or greenish color, can contain easily detectable quantities of uranium. Such uranium-containing glass is often referred to as canary or vaseline glass. In part, collectors like uranium glass for the attractive glow that is produced when the glass is exposed to a black light. Even ordinary glass can contain high-enough levels of potassium-40 or thorium-232 to be detectable with a survey instrument. Older camera lenses (1950s-1970s) often employed coatings of thorium-232 to alter the index of refraction.
Fertilizer
Commercial fertilizers are designed to provide varying levels of potassium, phosphorous, and nitrogen. Such fertilizers can be measurably radioactive for two reasons: potassium is naturally radioactive, and the phosphorous can be derived from phosphate ore that contains elevated levels of uranium.
Food
Food contains a variety of different types and amounts of naturally occurring radioactive materials. Although the relatively small quantities of food in the home contain too little radioactivity for the latter to be readily detectable, bulk shipments of food have been known to set off the alarms of radiation monitors at border crossings. One exception would be low-sodium salt substitutes that often contain enough potassium-40 to double the background count rate of a radiation detector.
Gas Lantern Mantles
While it is less common than it once was, some brands of gas lantern mantles incorporate thorium-232. In fact it is the heating of the thorium by the burning gas that is responsible for the emission of light. Such mantles are sufficiently radioactive that they are often used as a check source for radiation detectors.
Antique Radioactive Curative Claims
In the past, primarily 1920 through 1950, a wide range of radioactive products were sold as cure-alls, for example, radium-containing pills, pads, solutions, and devices designed to add radon to drinking water. The states generally have regulatory authority over these devices. In some cases, a state might even require that these devices be registered or licensed. Most such devices are relatively harmless but occasionally one can be encountered that contains potentially hazardous levels of radium. If there is any question about the safety of such devices, the public is strongly encouraged to contact the state radiation-control program for advice.
Information taken from a Health Physics Society Fact Sheet, "Consumer Products Containing Radioactive Materials," published in November 2002.
Additional Information
• National Council on Radiation Protection and Measurements, "Radiation Exposure of the US Population from Consumer Products and Miscellaneous Sources," NCRP Report No. 95, Bethesda, MD, 1987.
• US Nuclear Regulatory Commission, "Systematic Radiological Assessment of Exemptions for Source and Byproduct Materials, NUREG-1717, Washington, DC, 2001.
Sun tanning and Tanning Booths
A tanning booth uses ultraviolet (UV) light bulbs that emit UV radiation that causes the skin to tan. This result is similar to the sun’s effect on the skin.
An increased risk to cancer comes to those who use tanning beds, which is based on studies on individuals that have had skin cancer. It is now a well known fact that an increase in UV radiation also causes an increase in risk of skin cancer. This is why Dermatologists and Physicians recommend the general public to limit their exposure to natural sunlight as well as tanning booths.
The US Food and Drug Administration do recommend that tanning booths should be avoided. This doesn’t mean that everyone who uses a tanning booth will have an adverse health effect, just as people who go out in the sunlight unprotected from the UV will not all suffer harmful effects. We all need to be aware that some harmful effects like skin cancer take many years to appear.
Many health studies have been done on large groups of people and the experts have found that there is a significant increase in the risk of harmful health effects from UV light. The risk of harmful effects is not 100% even if you are exposed to UV every day, and the risk cannot be reduced to zero even if you completely eliminate UV exposure. But what you can do is minimize your risk by taking reasonable measures such as avoiding unnecessary or excessive exposure.
Ultraviolet radiation does not penetrate to any significant depth in the body, which is why the majority of cancer resulting from UV rays is majorly skin cancer. You should know that if these skin cancers aren’t caught in enough time they will carry throughout the rest of the body.
The eye also absorbs ultraviolet light wavelengths. If there is a significant exposure to the cornea, it can eventually cause a corneal burn that is quite painful but does repair itself over time. If the lens is exposed to ultraviolet light in a significant amount or chronically, cataracts can form.
I would recommend using sun block, but even with its aid you can still develop cancer. Sunblock will help lessen your exposure to UV rays, but is not totally effective in preventing skin cancer. One of the primary reasons is that it wears off and needs to be reapplied. If sunscreen is not applied often enough, it may give a false sense of security leading to even more time in the sun. A rough guide of when you should renew your Sunblock is roughly every 10 minutes.
When looking for a good Sunblock you should buy the more opaque the sunscreens. Not all sunscreens are equally effective. Some sunscreens are manufactured to block short-wave ultraviolet (UVB) radiation, which damages the skin's surface and causes redness and burning. Yet it is the longer-wave ultraviolet (UVA) radiation that penetrates deeper into the skin. Unfortunately, UVA radiation is less likely to cause noticeable sunburn symptoms, even though it severely damages the elastic fibers and collagen and is significant in producing malignant melanoma. The best sunscreens block both UVB and UVA rays. Both avobenzone and benzophenone are good UVA blockers. For maximum benefits, sunscreen must be applied evenly to cool, dry skin 30 minutes before sun exposure. Waterproof and water-resistant sunscreens are best since effectiveness is not reduced by perspiration.
Will general clothing worn outdoors stop ultraviolet radiation?
While outdoors one needs to know that different fabrics have different protection levels, the tighter the weave the greater the protection level. In addition, dark colors of the same material tend to absorb/block more ultraviolet (UV) radiation than light colors. Many fabrics tend to have a lower protection factor when wet. UV absorbers can be added to materials by clothing manufactures to enhance UV protection and those are sold specifically as UV-blocking clothing (and they are generally more expensive).
An increased risk to cancer comes to those who use tanning beds, which is based on studies on individuals that have had skin cancer. It is now a well known fact that an increase in UV radiation also causes an increase in risk of skin cancer. This is why Dermatologists and Physicians recommend the general public to limit their exposure to natural sunlight as well as tanning booths.
The US Food and Drug Administration do recommend that tanning booths should be avoided. This doesn’t mean that everyone who uses a tanning booth will have an adverse health effect, just as people who go out in the sunlight unprotected from the UV will not all suffer harmful effects. We all need to be aware that some harmful effects like skin cancer take many years to appear.
Many health studies have been done on large groups of people and the experts have found that there is a significant increase in the risk of harmful health effects from UV light. The risk of harmful effects is not 100% even if you are exposed to UV every day, and the risk cannot be reduced to zero even if you completely eliminate UV exposure. But what you can do is minimize your risk by taking reasonable measures such as avoiding unnecessary or excessive exposure.
Ultraviolet radiation does not penetrate to any significant depth in the body, which is why the majority of cancer resulting from UV rays is majorly skin cancer. You should know that if these skin cancers aren’t caught in enough time they will carry throughout the rest of the body.
The eye also absorbs ultraviolet light wavelengths. If there is a significant exposure to the cornea, it can eventually cause a corneal burn that is quite painful but does repair itself over time. If the lens is exposed to ultraviolet light in a significant amount or chronically, cataracts can form.
I would recommend using sun block, but even with its aid you can still develop cancer. Sunblock will help lessen your exposure to UV rays, but is not totally effective in preventing skin cancer. One of the primary reasons is that it wears off and needs to be reapplied. If sunscreen is not applied often enough, it may give a false sense of security leading to even more time in the sun. A rough guide of when you should renew your Sunblock is roughly every 10 minutes.
When looking for a good Sunblock you should buy the more opaque the sunscreens. Not all sunscreens are equally effective. Some sunscreens are manufactured to block short-wave ultraviolet (UVB) radiation, which damages the skin's surface and causes redness and burning. Yet it is the longer-wave ultraviolet (UVA) radiation that penetrates deeper into the skin. Unfortunately, UVA radiation is less likely to cause noticeable sunburn symptoms, even though it severely damages the elastic fibers and collagen and is significant in producing malignant melanoma. The best sunscreens block both UVB and UVA rays. Both avobenzone and benzophenone are good UVA blockers. For maximum benefits, sunscreen must be applied evenly to cool, dry skin 30 minutes before sun exposure. Waterproof and water-resistant sunscreens are best since effectiveness is not reduced by perspiration.
Will general clothing worn outdoors stop ultraviolet radiation?
While outdoors one needs to know that different fabrics have different protection levels, the tighter the weave the greater the protection level. In addition, dark colors of the same material tend to absorb/block more ultraviolet (UV) radiation than light colors. Many fabrics tend to have a lower protection factor when wet. UV absorbers can be added to materials by clothing manufactures to enhance UV protection and those are sold specifically as UV-blocking clothing (and they are generally more expensive).
Monday, March 29, 2010
Are you being exposed to Radiation when you walk through a scanner in Air Port?
Luggage Scanners-
There is nothing for you to worry about. An airport x-ray machine is very similar to x-ray machines used by federal and state agencies to screen briefcases and packages. They give off much lower doses than x-ray machines in hospitals. You could almost say they are immeasurable. They are designed this way because they do not have to see as much detail and are not designed for looking into very large objects. They are usually only looking for things that really stand out on images like metal.
The only devices in your luggage that you should be worried about would be your camera film, but since everything has gone digital these days you probably won’t even have to worry about that, as for food items the radiation coming from the airport exposure is too low to affect anything.
Pets are also safe, because only the pet carrier will be sent through the airport x-ray. The same goes for clothing; the radiation of the scanner is too small to degrade the materials. The manufactures of these scanners indicate that the radiation exposure to an item is about 1/10th of the exposure we get every day from natural radiation in our environments.
People Scanners-
It is true that some walk-through x ray scanners are actually being used to screen people before getting on an airplane. You might see one of these in a large international airport such as Heathrow in London.
You must remember next time you step into one of those scanners that there is actually very little radiation dose for a person passing through the scanner because they are not trying to see the detail of our "soft" tissues as is done in medical examinations. They are looking for items that will stand out pretty easily.
The American National Standards Institute, in its standard N43.17-2002 "Radiation Safety for Personnel Security Screening Systems Using X-Rays," the maximum effective dose an individual could receive when walking through this scanner is 0.01 mrem (millirem) For some perspective on the level of this dose, the annual effective dose each of us receives from background radiation is about 360 mrem; the effective dose from one chest x ray is about 10 mrem.
Metal Detectors-
This type of machinery does not expose you to ionizing radiation, neither do the wands that are used for individual screening. Metal detectors operate by generating a low-intensity magnetic field that passes from one side of the detector to the other. If metal objects pass through that field, the magnetic field will induce a second field in the metal object. Since that second field is a disruption of the first field, the detector senses the change and sets off an alarm. Magnetic fields are a form of radiation, but they are called "nonionizing" radiation. This means that magnetic fields do not generate additional, damaging radiation the way that ionizing radiation (or X rays) does. Magnetic fields below certain intensities are considered to be safe in that they will not cause any biological damage to an individual. As a reference, MRI (magnetic resonance imaging) is considered safe and uses much higher magnetic field intensity than a metal detector. In summary, because of its nonionizing properties, the magnetic field generated in a metal detector will not cause harm to persons even with routine and/or repeated scanning.
I work for a major airline and will be required to spend eight hours a day near the new baggage x-ray machines (the big ones that I think are CT machines) that TSA (Transportation Security Administration) uses. We have been given a handout saying that TSA has determined that the machines are not dangerous and that we do not need film badges. How can anyone say working near radiation is not dangerous if it is not monitored in any way?
Newer Luggage Scanners-
Some of the newer x-ray machines used to scan checked luggage use computerized tomography (CT) technology—just like those used in medicine. The main difference between the two types of use (security at airports and medical diagnosis) is that the machines used in airports have more shielding to stop the scattered radiation—nearly the entire luggage belt is shielded where, in medicine, the patient table is not shielded—and they subject the baggage to lower doses because the image does not need to be as clear as it does for a patient.
Someone standing next to the unit in airports would receive little, if any, radiation exposure. Radiation emitted around a piece of equipment when it is operating is determined at the manufacturer and, sometimes, checked by the purchaser. A manufacturer must assure the equipment is operating within federal regulations that govern x-ray equipment, which in this case is 0.5 mR/h at 5 cm from the unit (mR or milliroentgen is a unit of radiation exposure) though performance studies of the equipment indicate that the average exposure rate was about 0.08 μR (microroentgen, one-one thousandth of a milliroentgen) per scan (NCRP Report 95). Purchasers can use the manufacturer's assurance and/or can perform their own surveys on the equipment. The dose to the luggage is very low and there is no detectable radiation outside the machines according to one manufacturer.
There is nothing for you to worry about. An airport x-ray machine is very similar to x-ray machines used by federal and state agencies to screen briefcases and packages. They give off much lower doses than x-ray machines in hospitals. You could almost say they are immeasurable. They are designed this way because they do not have to see as much detail and are not designed for looking into very large objects. They are usually only looking for things that really stand out on images like metal.
The only devices in your luggage that you should be worried about would be your camera film, but since everything has gone digital these days you probably won’t even have to worry about that, as for food items the radiation coming from the airport exposure is too low to affect anything.
Pets are also safe, because only the pet carrier will be sent through the airport x-ray. The same goes for clothing; the radiation of the scanner is too small to degrade the materials. The manufactures of these scanners indicate that the radiation exposure to an item is about 1/10th of the exposure we get every day from natural radiation in our environments.
People Scanners-
It is true that some walk-through x ray scanners are actually being used to screen people before getting on an airplane. You might see one of these in a large international airport such as Heathrow in London.
You must remember next time you step into one of those scanners that there is actually very little radiation dose for a person passing through the scanner because they are not trying to see the detail of our "soft" tissues as is done in medical examinations. They are looking for items that will stand out pretty easily.
The American National Standards Institute, in its standard N43.17-2002 "Radiation Safety for Personnel Security Screening Systems Using X-Rays," the maximum effective dose an individual could receive when walking through this scanner is 0.01 mrem (millirem) For some perspective on the level of this dose, the annual effective dose each of us receives from background radiation is about 360 mrem; the effective dose from one chest x ray is about 10 mrem.
Metal Detectors-
This type of machinery does not expose you to ionizing radiation, neither do the wands that are used for individual screening. Metal detectors operate by generating a low-intensity magnetic field that passes from one side of the detector to the other. If metal objects pass through that field, the magnetic field will induce a second field in the metal object. Since that second field is a disruption of the first field, the detector senses the change and sets off an alarm. Magnetic fields are a form of radiation, but they are called "nonionizing" radiation. This means that magnetic fields do not generate additional, damaging radiation the way that ionizing radiation (or X rays) does. Magnetic fields below certain intensities are considered to be safe in that they will not cause any biological damage to an individual. As a reference, MRI (magnetic resonance imaging) is considered safe and uses much higher magnetic field intensity than a metal detector. In summary, because of its nonionizing properties, the magnetic field generated in a metal detector will not cause harm to persons even with routine and/or repeated scanning.
I work for a major airline and will be required to spend eight hours a day near the new baggage x-ray machines (the big ones that I think are CT machines) that TSA (Transportation Security Administration) uses. We have been given a handout saying that TSA has determined that the machines are not dangerous and that we do not need film badges. How can anyone say working near radiation is not dangerous if it is not monitored in any way?
Newer Luggage Scanners-
Some of the newer x-ray machines used to scan checked luggage use computerized tomography (CT) technology—just like those used in medicine. The main difference between the two types of use (security at airports and medical diagnosis) is that the machines used in airports have more shielding to stop the scattered radiation—nearly the entire luggage belt is shielded where, in medicine, the patient table is not shielded—and they subject the baggage to lower doses because the image does not need to be as clear as it does for a patient.
Someone standing next to the unit in airports would receive little, if any, radiation exposure. Radiation emitted around a piece of equipment when it is operating is determined at the manufacturer and, sometimes, checked by the purchaser. A manufacturer must assure the equipment is operating within federal regulations that govern x-ray equipment, which in this case is 0.5 mR/h at 5 cm from the unit (mR or milliroentgen is a unit of radiation exposure) though performance studies of the equipment indicate that the average exposure rate was about 0.08 μR (microroentgen, one-one thousandth of a milliroentgen) per scan (NCRP Report 95). Purchasers can use the manufacturer's assurance and/or can perform their own surveys on the equipment. The dose to the luggage is very low and there is no detectable radiation outside the machines according to one manufacturer.
Wednesday, March 10, 2010
Accountability of Radiation Europe to America
Why is it that America doesn't keep track of the skin entrance dose of all the radiographs that it takes on its own citizens?
Answer soon to come.
Answer soon to come.
How much can a radon mitigation system cost?
If you have successfully tested your home for radon gas and you have received your results they are positive for high radon levels of 4 picoCuries per liter (pCi/L) or higher. This is what you need to do.
Hire a qualified radon mitigation contractor to reduce the radon levels in your home
Decide an appropriate radon reduction method for your situation
Continue to maintain your radon reduction system
If you do these three suggestions you're health will benefit. Even though there are no immediate signs of Radon exposure, five to twenty five years down the road you may develop lung cancer. This is the only cancer directly related to being exposed to radon.
A national residential radon survey completed in 1991 to determine the average indoor radon level was about 1.3 picocuries per liter (pCi/L) in the United States. The average outdoor level is about 0.4 pCi/L. You may be wondering what you can do to reduce your exposure to Radon. I would recommend a Radon Reduction System.
Radon reduction systems have been proven to work. As a matter of a fact some radon reduction systems have been known to reduce radon levels in your home by up to 99%. The estimated cost of fixing a home with radon generally ranges from $800 to $2,500 (with an average cost of $1,200). Costs depend on the size and design of your home and also which radon reduction method is chosen. There are hundreds of thousands of people have reduced radon levels in their homes, so don't feel like you're the only one to have these kinds of problems.
Hire a qualified radon mitigation contractor to reduce the radon levels in your home
Decide an appropriate radon reduction method for your situation
Continue to maintain your radon reduction system
If you do these three suggestions you're health will benefit. Even though there are no immediate signs of Radon exposure, five to twenty five years down the road you may develop lung cancer. This is the only cancer directly related to being exposed to radon.
A national residential radon survey completed in 1991 to determine the average indoor radon level was about 1.3 picocuries per liter (pCi/L) in the United States. The average outdoor level is about 0.4 pCi/L. You may be wondering what you can do to reduce your exposure to Radon. I would recommend a Radon Reduction System.
Radon reduction systems have been proven to work. As a matter of a fact some radon reduction systems have been known to reduce radon levels in your home by up to 99%. The estimated cost of fixing a home with radon generally ranges from $800 to $2,500 (with an average cost of $1,200). Costs depend on the size and design of your home and also which radon reduction method is chosen. There are hundreds of thousands of people have reduced radon levels in their homes, so don't feel like you're the only one to have these kinds of problems.
Friday, February 26, 2010
Are cellular phones dangerous?
There has been tons of research done on the interaction of the cell phone on the human body. Many have come to believe that a cell phone is harmful. Cell phones are designed to be safe for both the user and anyone that many by chance standing nearby the user. Cell phones are actually small radios that transmit signals to and from base-station antennas located on towers or buildings in the nearby neighborhoods. Cellular phones use low-power radio signals, even weaker than CB, police, or fire radios.
Cellular phones and cellular phone base stations have been shown to meet these RF safety standards. A cell phone is always on whether you are using it to talk or not it’s constantly communicating to nearby base stations. These are similar to the waves that go to your radio so that you can hear your favorite songs while driving. The cell phone produces very low frequencies of Radiofrequency energy exposure to the user.
The FDA does have the authority to take action if cell phones are shown to emit radiofrequency energy (RF) at a level that is hazardous to the user. The American National Standards Institute (ANSI) sets safety standards for human exposure to radiofrequency (RF) electromagnetic energy in the United States. Government agencies such as the Federal Communications Commission (FCC), the Occupational Safety and Health Administration (OSHA), and many states recognize and accept the ANSI RF safety standard. Also the United States standard for RF energy is comparable to those set in other countries. With all the information and technology that we have currently we cannot prove that the RF energy used by cell phones pose any health threat to the public.
I would like to further indicate that nothing is "completely safe" everything has some associated risk. Although science has been reasearching EM (electromagnetic) feilds for over 50 years, they still have not answered wether these EM feilds casue cancer. The question you should be asking yourself is if the risk is worth the benifit.
Consider checking the Motorola cell phone sight below to see what they have to say about this topic.
http://www.motorola.com/staticfiles/Business/Corporate/US-EN/corporate-responsibility/consumers/wireless-communications-and-health.html
Cellular phones and cellular phone base stations have been shown to meet these RF safety standards. A cell phone is always on whether you are using it to talk or not it’s constantly communicating to nearby base stations. These are similar to the waves that go to your radio so that you can hear your favorite songs while driving. The cell phone produces very low frequencies of Radiofrequency energy exposure to the user.
The FDA does have the authority to take action if cell phones are shown to emit radiofrequency energy (RF) at a level that is hazardous to the user. The American National Standards Institute (ANSI) sets safety standards for human exposure to radiofrequency (RF) electromagnetic energy in the United States. Government agencies such as the Federal Communications Commission (FCC), the Occupational Safety and Health Administration (OSHA), and many states recognize and accept the ANSI RF safety standard. Also the United States standard for RF energy is comparable to those set in other countries. With all the information and technology that we have currently we cannot prove that the RF energy used by cell phones pose any health threat to the public.
I would like to further indicate that nothing is "completely safe" everything has some associated risk. Although science has been reasearching EM (electromagnetic) feilds for over 50 years, they still have not answered wether these EM feilds casue cancer. The question you should be asking yourself is if the risk is worth the benifit.
Consider checking the Motorola cell phone sight below to see what they have to say about this topic.
http://www.motorola.com/staticfiles/Business/Corporate/US-EN/corporate-responsibility/consumers/wireless-communications-and-health.html
Friday, January 22, 2010
EPA Map of Radon Zones
This map doesn’t include the Puerto Rico (this is under development)
The purpose of this map is to assist National, State, and local organizations to target their resources and to implement radon-resistant building codes. This map is not intended to be used to determine if a home in a given zone should be tested for radon. Homes with elevated levels of radon have been found in all three zones. All homes should be tested regardless of geographic location.
Zone 1 counties have a predicted average indoor radon screening level greater than 4 pCi/L (pico curies per liter) (red zones) Highest Potential
Zone 2 counties have a predicted average indoor radon screening level between 2 and 4pCi/L (orange zones) Moderate Potential
Zone 3 counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones) Low Potential-If you have any problems seeing the words on this Radon Map of Idaho, just click to enlarge.
How to get your house tested for Radon
About 7% of homes in the U.S. have unsafe Radon Gas levels.
There are four types of Radon Test Kits. Long Term, Short Term, Private Well Water Radon Test Kits and an Electronic Radon Gas Detector.
The Long Term Radon Test Kits (Accutar Alpha Track Test Kit AT 100)are used in situations where they are exposed to changes in seasons, temperature and humidity. These tests last from 3 to 12 months, it works by taking air samples from inside your house. The expected cost for a Long Term Radon Test is normally $28.
The Short Term Test Kits (AccuStar Charcoal LS CLS 100i Short Term Radon Gas Test Kit) is most commonly used when quick results are needed. When using this type of test it is recommended that you use 2 test kits and place them side by side about 4 inches apart to help rule out inaccuracy. This testing takes 48 to 96 hours. The anticipated cost of the Short Term Test Kit is also $28.
There are also ways to test the radon levels of your well water. The Accurstar WTR-100 Private Well Water Radon Test Kit The estimated cost of the Radon Water Test Kit is $36. When the test is complete, you will need to send the test kit to the Radon testing Lab. Analysis should take only one business day to obtain your results.
If you are interested in continuing your tests you may look into obtaining a Safety Siren Pro Series 3 Electronic Radon Gas Detector with LED Digital Readout. This is the ideal product for homeowners & smaller business. This can be used for both short term and long term testing and monitoring. This is a very simple device that plugs into a standard AC house outlet and displays a digital reading in approximately 48 hours after being plugged in. The reason for the long delay is due to the fact that the EPA considers a test less than 48 hours to be invalid. The projected cost of this Electronic Radon Gas Detector is $165.
If you would like to order one of these Test Kits I received the majority of my information and prices from this web site.
http://www.4radon.com/
The following question came up during our Radiation Protection Class. "If a pilot was to fly a night would this reduce the amount of radiation that the pilot and crew would be exposed to?" In my search to answer this question I contacted Richard Brey, a Professor of Physics at the Idaho State University and this was his reply.
Ben,
To answer your question directly; no, there is little anticipated difference in the ionizing radiation exposure received during the day or at night. Very little of the cosmic ionizing radiation exposure received by humans is associated with solar radiation. Although our sun does produce ionizing radiation that source of ionizing radiation is greatly deflected by the Van Allen Belt which surrounds the earth. The Van Allen radiation belt is a torus of energetic charged particles (plasma) around Earth, which is held in place by Earth's magnetic field. Cosmic radiation exposure on the surface of the planet is related to extremely high energy particles and waves generated by other stars in our universe. This radiation sometimes serves as a source of direct exposure, and it frequently generates secondary radiation when it interacts in the earth's atmosphere. Some of the radiation exposure we receive is associated with the secondary particles generated by spallation reactions in the atmosphere. Some of the exposure is associated with the so called cosmogenically produced radioactive material such as C-14, H-3, and Be-7. A good reference on this subject is NCRP Report No. 160 which was published in 2009 and is entitled Ionizing Radiation Exposure of the Population of the United States (ISBN : 978-0-929600-98-7). This may be purchased on-line from NCRP (The National on Radiation Protection and Measurements). The NCRP web-page may be found at: http://www.ncrponline.org/. To find a copy of the report described above simply click on the Publications tab. I hope this is helpful.
Richard Brey, Ph.D., C.H.P.
Professor of Physics
Director, ISU Health Physics Program
Subscribe to:
Posts (Atom)