Healthy Radiation? The Benefits and Danger of Medical Isotopes

Out of all the man-made radiation we are exposed to every year, more than half comes from diagnostic x-rays.  Medical tests and treatments that make use of radiation have a huge range: from simple dental procedures to aggressive radiation therapy for cancer patients.  Physicians use x-rays in more than half of all medical diagnoses to determine the extent of disease or physical injury¹.  The kind of radiation that medical professionals use is generally strong at first, but has a short half-life (weakens quickly) and isn’t readily absorbed into the body.  This way the radiation is out of the patient before it has time to do much damage. 

Most medical isotopes are used for imaging, whether they are ingested, inhaled, or injected into the body.  These materials are easily picked up by x-ray machines and other types of detectors, allowing specialists to track the flow of fluids in the body. The most common isotope used for imaging is technetium-99m, which is used for nearly 80% of diagnostic imaging procedures².  Common isotopes for radiation therapy include yttrium-90 and iodine-131.

The vast majority of all concentrated radiation that a normal person runs across comes from medical sources.  In fact, we here at D-tect Systems recently ran across a mysterious source.  Even though medical isotopes are generally carefully controlled and disposed of, many landfills get quite a steady influx of medical radiation.  We recently received permission to take a few samples of a mysterious radiation source in the Trans-Jordan Landfill located at the south end of the Salt Lake Valley.  Like many landfills in the United States, the Trans-Jordan Landfill has a set of huge portal monitors for scanning all incoming loads for radiation.  We were told that loads of scrap metal almost invariably set off the detectors, as well as other materials.

The object of our inquiry was a strong radiation source in a black plastic bag that that landfill workers had located and were observing.  We brought in the D-tect Systems Rad-ID system (a handheld isotope identifier) to see if we could figure out what the mystery isotope was.  It was definitely a strong source – it set off the highest level on our MiniRad-D detector from several meters away.  After a few tests, we found it the source contained at least two medical isotopes: Barium-133 and Radium-226.  These isotopes are commonly used in conjunction in medical treatments.

So how can you make sure medical isotopes are worth the risk?  Talk to a doctor.  Health care personnel take radiation very seriously and use it on a case-by-case basis.  Before receiving x-rays or other types of medical treatments involving radiation, discuss the risks and benefits of the procedure and make sure it’s worth it to you. 

If you’d like more information on radiation in medicine, we invite you to visit World Nuclear Association’s page.  It contains lots of good basic information on radiation usage in medicine as well as technical details on different isotopes.

1) http://www.epa.gov/radiation/docs/402-k-07-006.pdf

2) http://ie.lbl.gov/toi/

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D-tect Systems is a supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

D-tect Systems Featured on KSL News!

Check out this great article that KSL News published over the weekend! It talks about local homeland security companies and reports on our recent trips to Japan and has some great information and photos of D-tect products in the field.

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D-tect Systems is a supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

  

Relative Biological Effectiveness - What Kind of Radiation is the Most Risky?

As you read this right now, you are being bombarded by radiation – cosmic rays flying in from the dark reaches of space, photons streaming out of the hot core of the earth, and miniscule particles issuing from your computer and other objects around you. But not all radiation is created equal. A new field of study has unearthed the fact that different kinds of radiation affect us differently.  

Although quite a mouthful, this study is called Relative Biological Effectiveness (abbreviated RBE). It seeks to put all radiation on an equal plane and find out what kind poses the highest risk to our organism. Higher values of RBE mean that certain types of radiation are more harmful. Ionizing radiation, which is made up of alpha, beta, and gamma rays, constitute electrically charged particles that interact with matter. These interactions can cause ionization, which refers to changes within the structure of an atom that can cause it to destabilize or behave differently.

Alpha particles are the largest kind of ionizing radiation, each consisting of two protons and two neutrons. Because they are highly charged and quite large, they are quickly stopped by as little as 4 cm (1.4 inches) of open air or a sheet of paper¹. Beta particles are much smaller, meaning they can penetrate further: through 9 meters (19 ft) of open air or 11 mm (.4 inches) of body tissue. Gamma rays are high-energy photons, meaning that they penetrate much further and interact differently with matter than alpha or beta particles. Thick, dense materials such as lead are necessary to block gamma rays. Another related form of radiation is neutron radiation, which is commonly referred to as indirectly ionizing radiation. Free neutrons, which are emitted from nuclear materials such as uranium and plutonium, have about a quarter of the mass of an alpha particle². Neutrons are not charged but readily cause ionization by knocking away electrons or slamming into atomic nuclei. The neutral charge of these fast-traveling neutrons also allows them to penetrate much further into most materials than other types of ionizing radiation, even through many feet of concrete.

Source: American Nuclear Society

 To test how damaging different types of radiation is on the human body, scientists expose living tissue to equal amounts of energy from each type. Surprisingly enough, scientists have found that beta and gamma radiation are nearly equally damaging, so the RBE value of beta and gamma radiation is 1. It gets more complicated from here, though. Alpha and neutron radiation have different RBE values depending on what kind of cells are exposed to them. The RBE for bacteria is 2-3, but can be 6-8 for more complex cells like those found in the human body. This means that a certain amount of alpha radiation is 6-8 times more damaging then the same amount of beta radiation. Neutrons are even more damaging with a RBE of 4-6 for bacteria and 12-16 for complex cells³.  

The high RBE values of alpha and neutron radiation should make us think twice about how we deal with these types. Because incoming alpha particles are stopped by a single layer of skin, they can’t do much damage unless they get in our bodies. That’s why breathing in alpha radiation (from radon or radioactive dust) or ingesting it (in contaminated food or water) is so dangerous. When alpha particles get to really important cells in our organs, the RBE can shoot up: scientists have measured RBE values of 1,000 for alpha radiation inside hamsters⁴. Neutron RBE values are more constant because neutrons penetrate just about everything, but they are also much harder to contain. That’s why materials that emit neutrons are highly controlled, very hard to transport, and large neutron sources are only found in research facilities and power plants.

The Rad-ID device by D-tect Systems has a special way of finding neutron radiation. A container filled with Helium-3, a rare and stable gas, is included with other radiation detectors inside the Rad-ID. As neutrons shoot through the detector, they collide with some of the He-3 atoms, causing them to change into charged particles. These particles are quickly identified and counted by a detector and a measurement of this radiation is sent to the user. Since neutron sources give off varying levels of gamma radiation, the Rad-ID can also identify these materials and let the user know what they are dealing with.

The Rad-ID can detect neutron radiation sources.

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D-tect Systems is a supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

  

Radioactive Half-Life: How Long Will It Last?

Although it seems like this post should include some commentary on zombies or video games, we’re going to focus on the term ‘half-life’ as it’s used in physics, this time. The reason for this is that important research has been published last month on geothermal heat produced by radioactive decay. 

But before all that complicated stuff let’s start at the beginning. ‘Half-life’ is actually shortened from ‘half-life period’ which refers to the time in which exactly half of a radioactive substance decays. This measurement is especially useful because radioactive materials decay exponentially – meaning that they decay much more quickly at first than later on, where the decay process drags on more slowly.  This decay rate is directly connected to the rate at which radioactive materials emit radiation.  

Let’s take iodine as an example. I-131 has a radioactive half-life of just over 8 days and gives off both alpha and beta radiation (for a discussion of these radiation types see this post). As I-131 atoms give off radiation they transform into atoms of Xe-131, a stable (and non-radioactive) isotope¹. That means if you start with a pure sample of I-131, after 8 days about half of the sample will be I-131 and half will be Xe-131. If you wait another 8 days, 1/4 of the sample will be I-131 and 3/4 will be Xe-131, and so on. As you may expect, the sample of I-131 will emit much more radiation right at first versus many days later on, when the majority of the sample is Xe-131. 

 Not all materials have a half-life short enough to notice. In fact, the half-lives of radioactive materials can vary from fractions of a second to billions of years. These differences lend themselves to varied applications. Isotopes with short half-lives (such as I-131, Tl-201, In-111, and Tc-99) are commonly used in medical imaging and therapy because they show up clearly in the body and become non-effective quickly so that the patient is not exposed to too much radiation². Isotopes with long half-lives (such as U-238, C-14, and K-40) are often used in radiometric dating, where scientists can measure the abundance of these isotopes in various materials to determine their age³.

Newly published research⁴ from Japanese and Italian scientists also suggests that over half of the internal heat produced by the earth is caused by long-lasting radioactive materials such as thorium, uranium, and potassium – a quantity that adds up to nearly twice as much energy used annually by everyone on the planet⁵. The fact that radioactive materials are responsible for the heat is important because it helps to explain why our earth is hot enough to produce volcanoes, mountain ranges, and general plate tectonics while other planets in our solar system have long since gone cold. The geothermal heat of our planet isn’t going to cool soon either, thanks to the fact that the isotopes producing the heat have half-lives of billions of years.    

So although the adage “all good things must come to an end” (and all bad ones, too!) may be a great application to radioactive materials, there’ll be plenty of radiation and geothermal heat for years to come.

1)http://epa.gov/radiation/radionuclides/iodine.html

2)http://www.world-nuclear.org/info/inf55.html

3)http://www.world-nuclear.org/info/inf55.html

4)http://www.eurekalert.org/pub_releases/2011-07/dbnl-wkt071311.php

   5)http://www.scientificamerican.com/blog/post.cfm?id=nuclear-  fission-confirmed-as-source-2011-07-18   

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Meth - the Dark Crystal

Although this blog has mostly focused on radiation detection, we also have quite a bit of expertise in the chemical detection field, and we support law enforcement in their mission to mitigate threats to the public from drug production and chemical accidents.

From its street cost to the health effects it causes, the drug methamphetamine (meth) is expensive – an ounce of pure meth is worth up to 10 times than of an ounce of pure gold. The real problem with meth usage is that the meth’s cost to users in consumption and health problems is dwarfed by meth’s cost to society. This cost comes in the form of increased funding to health care, law enforcement, and cleanup procedures, and was estimated at $23.4 billion dollars in 2010¹.

source

 The most common source of meth is small home labs – the DEA reported 11,239 meth lab seizures last year alone² – which are often set up in motels, trailers, and rental properties. The production of meth involves a number of extremely hazardous chemicals, including:

·  Acetone

·  Ammonium Sulfate

·  Sulfuric Acid

·  Methanol

·  Mineral Spirits

·  Muriatic Acid

·  Organic Ether

·  Toluene

These chemicals are often absorbed into the walls, floor, and ceiling of a meth lab home and cause serious health problems for its residents for years to come. Take this example of a family from Tennessee that was featured in a New York Times article:

The spacious home where the newly wed Rhonda and Jason Holt began their family in 2005 was plagued by mysterious illnesses. The Holts’ three babies were ghostlike and listless, with breathing problems that called for respirators, repeated trips to the emergency room and, for the middle child, Anna, the heaviest dose of steroids a toddler can take. Ms. Holt, a nurse, developed migraines. She and her husband, a factory worker, had kidney ailments. It was not until February, more than five years after they moved in, that the couple discovered the root of their troubles: their house, across the road from a cornfield in this town some 70 miles south of Nashville, was contaminated with high levels of methamphetamine left by the previous occupant, who had been dragged from the attic by the police. The Holts’ next realization was almost as devastating: it was up to them to spend the $30,000 or more that cleanup would require.

Stories like this are in nowise uncommon; there are an estimated 1 to 1.5 million homes that are previously or currently being used to produce meth³. Although most of these homes appear no differently than other residences, many working meth labs do exhibit telltale signs, including:

 

·   Storage of large amounts of household items such as the chemicals listed above, matches, salt, Coleman fuel, plastic containers, coolers, and aluminum foil

·  Accumulation of garbage including red- or yellow-stained rags and coffee filters, latex gloves, empty cans, bottles, and plastic tubing

·  Chemical staining on walls and floors

·  Covering or blacking-out of windows

·  Security measures such as cameras or baby monitors outside of buildings or guard dogs

·  Unusual traffic patterns, such as excessive night traffic or large numbers of visitors with short stays

·  Burn pits, stained soil or dead vegetation indicating dumped chemicals or waste from a meth lab

·  Abnormal chemical odors not normally associated with apartments, houses or buildings. These odors may be similar to sweet, bitter, ammonia or solvent smells

More sophisticated equipment is often used by law enforcement to monitor meth lab activities and find areas that may be contaminated by previous meth lab use. D-tect Systems’ Chem-ID is a valuable asset in this search. The Chem-ID is a portable chemical detector that can identify over 100 different chemicals including many of those used in the production of meth. This device can identify multiple chemicals at once, and can even identify chemicals at a concentration as low as several parts-per-billion. The Chem-ID can gather samples near a suspected meth lab and analyze them on the spot, giving law enforcement valuable information about the status of the site.

The Chem-ID being operated remotely via Bluetooth

To find more information on meth, check out the Drug Enforcement Agency’s website at www.dea.gov or www.methlabhomes.com, an excellent nonprofit website with up-to-date statistics and news reports.

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Radon: Radiation on the Home Front

It seeps up through the ground, pooling in basements and cellars. It can infiltrate our homes and even our lungs, spreading radiation with every ripple of breeze. Present in nearly every country of the world, this substance is colorless, odorless, and tasteless. It kills thousands every year and requires special equipment to locate.

Although this sounds like something from a cheesy science fiction film, radon gas is a real threat to people all over the world. Radon-related diseases cause about 21,000 deaths per year in the US¹ (almost twice the number of drunk driving deaths), meaning in most countries only smoking causes more deaths from lung disease.

Deaths Per Year - Source: http://www.epa.gov/radon/pubs/citguide.html

The first reason radon is dangerous is because it’s all around us. The EPA estimates that 1 out of every 15 homes in the US has elevated radon levels² . In almost every country radon is the largest natural source of human exposure to ionizing radiation and makes up over half the radiation each person is exposed to in a year. Since radon is a decay product of uranium, it is more often found where there are large concentrations of granite, like those occurring in Ireland and the UK, Canada, and some US states such as Iowa and Pennsylvania.  

Radon Test Kit - Source: http://visualsonline.cancer.gov

The physical properties of radon also contribute to its effect on people.  Radon is one of the most dense gases on our planet – over 8 times denser than the atmosphere at sea level. This causes it to pool at the bottom of whatever container it is in. Because of this, elevated radiation levels from radon are found in the lower levels and basements of buildings. It also means that when breathed in, radon gets trapped in the bottom of the lungs and has more potential to do damage. Radon emits mostly alpha radiation which is made up of fast-moving particles with more mass than beta or gamma radiation. Alpha radiation doesn’t penetrate very well – it can be stopped by as little as a piece of paper or human skin. So the real risk to humans from alpha radiation is when it gets inside us and starts to affect our internal organs. Because it is a gas, almost all the damage done is in the lungs and can lead to lung cancer.   

The good news about radon is that it is easily detectable and many options are available to lessen radon risks in the home. Short- and long-term radon test kits are inexpensive and commercially available throughout the world. A short-term test (which takes several days) gives the homeowner an estimate of radon concentration in the home, and a subsequent long-term test (which takes a year or more) can give a more precise measurement. There are varying ‘action levels’ of radon throughout the world, but most countries recommend taking some action to reduce radon if average concentrations are above 4 pCi per liter of air³. Solutions to lower radon concentrations include venting air from lower stories of a house or pressurizing areas to keep external gases out.

An example of radon venting from the US EPA.

Although radon may sound scary and looks pretty bad on paper, many people can significantly lower their risk of radiation exposure from radon. Good information is widely available on this subject, including the World Health Organization’s Radon Handbook and A Citizen’s Guide to Radon by the US Environmental Protection Agency.  

1) http://www.epa.gov/radon/pubs/citguide.html

2) http://www.epa.gov/radon/pubs/citguide.html

3) http://www.who.int/mediacentre/factsheets/fs291/en/index.html

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Relative Doses of Radiation

As we've discussed earlier on this blog, to truly understand the health threat that radiation poses we have to put radiation in perspective. To help with this, we've just released a page that lists a number of relative doses of radiation and how they compare to the alarm levels of the MiniRad-D radiation detector. When it detects radiation, the MiniRad-D displays a number from 1 to 9 to indicate the strength of the radiation. The ranges of these numbers are listed on the graph and compared with varying radiation doses.

Because the MiniRad-D is a very sensitive device, lower levels of radiation that it picks up pose almost no health threat at all.

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Immersed in a Sea of Radiation

You don’t have to look far to find radiation in the world around us. In fact, the vast majority of radiation that we are exposed to throughout our lives comes from natural sources. Naturally Occurring Radioactive Materials (NORM) are very common in the environment and can be found in many products in our homes and cars. These materials generally pose very little, if any threat to our health, and it may surprise you how many everyday items have radioactive properties.

This rock from southern Utah contains Thorium-232.

The most common NORM contain radioactive isotopes of uranium, thorium, and potassium, as well as the isotopes these decay into (such as radium and radon). Although  much of the earth’s surface contains very low concentrations of radioactive materials, NORM is concentrated in many raw industrial products and activities such as the following:

Coal: although other rocks in the earth’s crust have approximately the same concentration of NORM, the large quantities of coal needed to fuel much of the world’s energy demands are responsible for a sizable amount of radiation and a wide variety of isotopes including potassium, lead, and radium. An interesting fact about NORM in coal is that the naturally occurring uranium contained in coal could be a fuel source more powerful than the coal itself if used in a certain type of nuclear reactor¹. 

Phosphate Rock: mainly used for fertilizers, phosphates can have much more concentrated amounts of NORM than other mining products. The radioactive content of phosphates has attracted media attention after European fertilizer manufacturing had been found responsible for radioactive material in the Atlantic.

Granite: this type of stone has traces of uranium in it, which means that many federal buildings such as the United States Capitol are faintly radioactive. We’ve found that the MiniRad-D (a small radiation detector) reads a constant radiation level of 2 around the perimeter of the Utah State Capitol, which has a granite facing on its exterior. Radiation measurements on granite surfaces can even show comparable levels to those from low-grade uranium mine tailings.

Oil and gas production: most of the radioactive material brought out of the ground in oil and gas production is deposited in pipes and other equipment. The concentration of NORM has made the resale of used equipment more difficult in recent years.

Although industrial activities are responsible for large amounts of NORM, many common household items also have significant amounts of radiation. Here are a few examples:

Smoke detectors: one of the most radioactive items in a home is the smoke detector, which uses an isotope of americium to sense the presence of airborne particles carried by smoke.

A small Americium-241 pellet from a smoke detector is contained in the plastic holder on top of the MiniRad-D device.

Ceramics: some of the most famous antique radioactive items are Fiesta Ware ceramics, which were produced from 1936-1943². The red glaze on these dishes contains Potassium-40, as do  the glazes of other ceramics with red, yellow, green, and black colors. The clay itself used in some ceramics can also contain NORM. Ceramic products such as bathroom tiles and porcelain can also show up on a radiation detector.

Cat litter: the main ingredient of cat litter is clay, which like that used in ceramics, often contains low levels of NORM.

Colored glass: uranium was commonly used as a coloring agent in yellow and green glass produced in the first half of the 20^th century. You can find antique dinnerware, home décor, and even children’s marbles that emit a measurable amount of radiation.

These antique marbles contain trace amounts of uranium.

Glossy paper: Kaolin, a substance known as “white gold” for its versatility and value, was commonly used to create glossy paper on magazines in the early 1900s. Kaolin contains clay with low concentrations of uranium and thorium.

Instrument dials: due to its ability to fluoresce, radium was used in paint for marking instruments and watch dials. This paint exhibits a bright green color when fluorescing.

Spark plugs: dating back to 1940, some old spark plugs contain an isotope of polonium that was used to make a more brittle alloy that readily creates sparks.

Lantern Mantles: old Coleman lantern mantles contain low levels of Thorium-232, an isotope with a 14 billion year half-life. Special care should be used when dealing with used mantles to ensure the radioactive dust isn’t breathed in.

A Coleman lantern mantle with a MiniRad-D detector.

Food: many foods contain trace amounts of radiation, including potatoes, bananas, kidney beans, and Brazil nuts. Salt substitute, which contains potassium chloride instead of sodium chloride, may also have a low level of radiation due to the presence of Potassium-40.

1) http://www.world-nuclear.org/info/inf30.html

2) http://www.orau.org/ptp/collection/consumer%20products/consumer.htm

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.

Isotope Identification: How Does it Work?

Although we can’t feel, see, or hear it, we live in a sea of radiation. Cosmic rays from outer space continually bombard our planet, natural radioactive materials produce a steady stream of radiation, and many man-made materials constantly emit radiation in our homes and vehicles. Although much of this radiation is weak and harmless, there are some sources, as well as elevated radiation levels, that are best avoided. This is the reason that isotope identification is so important.

The term isotope is often misunderstood: not all isotopes emit radiation. Rather,  the term isotope has to do with the number of neutrons in the nucleus of an atom. Each element is defined by a set number of protons (or atomic number), by which it is listed on the Periodic Table. Iodine, for example, has 53 protons. But there are different versions or isotopes of iodine with varying numbers of neutrons, which are denoted in the isotope name. I-127 is the most common isotope of Iodine and is stable, meaning that its atoms don’t give off radiation or change to other isotopes.  But I-129 and I-131, which are produced in nuclear processes, are unstable and give off radiation that can be dangerous.

Isotope identification consists of finding out which radioactive isotopes are responsible for radiation. It is possible to figure this out by closely measuring the energy levels of radiation. Each radioactive particle or photon has a certain energy level, and each radioactive isotope emits a different set of energy levels. For example, here is a radiation measurement taken by a Rad-ID device:

Isotope Identification from the Rad-ID

As you can see, there are two energy peaks (at 25 keV and 88 keV) shown on the graph.  These two peaks appear because the isotope gives off a higher percentage of 25 keV and 88 keV radiation than radiation at other levels. By matching these measured energy peaks to pre-programmed energy peaks for known radioactive isotopes, isotope identifiers can narrow down and found out which isotopes are emitting the radiation.

There are a few difficulties that occur in the isotope identification process. First, no matter how well a radiation reading matches the pre-programmed energy levels, there is always at least a slight chance of an incorrect identification. This probability grows dramatically if the measured radiation levels can’t be matched very well. This is why it’s important to understand how good the match is and if there are lots of isotopes involved. Confidence bars can help out with this. Another problem is shielding. These two pictures show measurements an unshielded source on the left and a shielded source on the right:  

If you look closely at the two pictures you'll notice that a large energy peak on the left side of the first  (unshielded) reading is missing in the second. This  happens because shielding tends to block high-energy photons much better than the low-energy ones, which penetrate better. This can drastically change the shape of radiation measurements, and with enough shielding, completely block the radiation.

Measuring energy levels precisely enough to make an identification takes a very specialized instrument, different than a normal radiation detector. Identifiers usually have a LaBr3 or CZT detector, as does the Rad-ID.  These detectors are much more accurate than other types of radiation detectors. The Rad-ID also uses a large scintillation detector (NaI(Tl)), a Geiger-Mueller detector and an optional He3 tube to find a wide range of gamma and neutron radiation. In fact, the Rad-ID can identify 107 different radioactive isotopes, even if a measure sample is reading radiation from several isotopes.

With a good isotope identifier, you can be sure that you know what isotopes are in the environment and if you need to worry about them.

D-tect Systems is supplier of advanced radiation and chemical detection equipment sold around the world. www.dtectsystems.com.