[Music] well hello and welcome to the radiation Basics training my name is Army Ansari a health physicist at the Centers for Disease Control and prevention now if you're participating in this training you may be a public health professional a clinician a law enforcement official a first responder or someone who wants to know more about radiation and radioactivity and you are in the right place now the word radiation carries a negative connotation for many of us it's not something we want in our lives generally but the truth is that radiation is all around us every day we're exposed to radiation constantly from radiation that comes to us from outer space elements in the ground the food we eat and the air we breathe and these everyday exposures don't do us any harm because our cells and our bodies have evolved and adapted to living in these conditions just like any other life form on Earth so it's important to keep this context in mind as we explore and evaluate additional exposures to radiation now this training gives you a basic understanding of of radiation and radioactivity and prepares you for more advanced training radiation Basics is divided into eight segments in these segments we will discuss sources of radiation radioactive decay measuring radiation biological effects of radiation radiation protection decontamination environmental impact of radio activity responding to radiation emergencies after you complete this training I invite you to visit our website where you will find additional resources and training products and if you have any comments on this particular training or other products you see on our website please email us your comments now thank you again for your interest in this topic and let's get [Music] started now in this training whenever we talk about radiation we're really talking about ionizing radiation so let me first describe to you what radiation is and then tell you what's different about ionizing radiation radiation means energy that originates from a source and then travels through space at the speed of light and this energy has an electric field and a magnetic field associated with it and it has wav likee properties so a more technical term for it would be electromagnetic wave but we just call it radiation the most familiar form of radiation is actually visible light visible light is electromagnetic waves it's energy that originates from a source and travels through space at the speed of light it has wavelengths and frequencies that defines its energy and if we're blessed with good Vision we can actually see this radiation we can detect it with our eyes and see this radiation and the difference between colors of light know red green blue and so forth is in their energy wavelength that's what sets them apart and that's how we can detect them so different colors of light are actually radiation of different energies that we can see now the the spectrum of visible light that we see the range of visible light the different colors is only a tiny fraction of the entire spectrum of electromagnetic radiation in nature the Nature has radiation with energies that are far less and are far higher than visible light so if we start in the range that we can see and start with red which has the lowest Energy red light has lower energy than blue light so let's say we start with red and go down in energy we go to infrared microwaves radiation from cell phones radio waves these are all forms of radiation that have less energy than visible light and of course they're invisible to us now if we go higher energy let's start again come back to the visible spectrum and go to Blue Light which has a high energy then purple then we go to Ultra Violet and x-rays and gamma rays these types of radiation have much much higher energies than visible light and of course we can see them but we have detectors instruments that can detect these types of radiation and in other segments I'm going to show you how we do that but we have instruments that can detect these types of radiation just like we have instruments that we can measure the intensity of visible light we have light meters that do that we can detect it with our eyes of course and then radios radios we can tune into frequencies in the radio frequency and do that so we have instruments U to deta all types of radiation in fact it's interesting because at any moment all the radiation signals that carry information for all our favorite radio stations and television stations are all here in this room it's just a matter of having the right instrument to tune into it I want to talk about ionizing radiation which is X-rays and gamma rays so what happens at the higher energy side of the El magnetic Spectrum these forms of radiation interact with matter they have enough energy to remove an electron from an atom and when they do that the atom becomes charged or ionized so that's why we call these ionizing radiation because they have a capability to ionize atoms when they interact with them this is a unique property that is other these other forms of radiation including what we get out of a cell phone don't do that so in this training we're going to focus exclusively on ionizing radiation even though we might just say radiation for Simplicity what really mean what we really mean is ionizing radiation so where does ionizing radiation come from well our nature ionizing radiation comes from radioactive atoms and uh radioactive atoms just like any other atom as you know are building blocks of matter so it could come in solid form U it could come um in the form of gas like this or liquid so just like any other matter radioactive material or radioactive atoms are part of matter they could come in gas liquid or solid but what makes an atom radioactive as you know atoms are composed of a nucleus and have a cloud of electrons that surround them in the nucleus we have protons and neutrons and it needs to be a good balance between protons and neutrons for the atom to feel stable let's take carbon for example now carbon has six protons and six neutrons and that's a pretty happy carbon atom because it's pretty stable proton determines what the identity of the atom is so if you take the carbon atom and we add an additional proton seven it's no longer carbon it becomes nitrogen nitrogen has seven protons and nitrogen likes to have seven neutrons to be happy and stable often you see in this training also we would follow the name of the element with a number say nitrogen 14 or carbon 12 that number number is the atomic mass number is a summation of protons and neutrons the sum of protons and neutrons so that number that's what it refers to so nitrogen with seven protons and seven is a stable nitrogen seven nitrogen 14 is Happy carbon six and six is a stable carbon atom but carbon 14 which we see in nature and we'll talk about later has uh six protons which makes the carbon but eight neutrons so it has two additional neutrons and that's an unstable a nucleus and it's radioactive because unstable nucleus doesn't like to remain unstable it likes to reach a more stable State and what it does is ejects some of that extra energy ejects it out to reach a more stable State and this process I just described is radioactivity so let's discuss some key terms radioactivity then is the spontaneous release of energy from an unstable atom radioactive material could be a solid liquid or gas that contains radioactive atoms and radiation is the energy that comes out of the radioactive atom radioactive isotopes and sometimes we call that radio nucleid are radioactive atoms of the same element that they have different numbers of neutrons an example would be iodine iodine 131 or iodine 125 now these are both iodine element is iodine but they have different number of neutrons and they're both radioactive so we call these radio nucle slides or radioactive isotopes and then radioactive decay is that process the change going from un from an unstable atom to a more stable atom by emitting radiation so the carbon 14 that I mentioned earlier the carbon 14 atom would go through a radioactive decay process expel some of that extra energy and change back to a nitrogen 14 so carbon 14 will go to nitrogen 14 which is a more stable atom you uranium also be find in nature uranium would go through radioactive decay process and transform into an atom of thorium which is a more stable atom but sometimes even the atom that it transforms into still needs to go through more processes the thorium is still radioactive has less energy than radium than uranium but it still needs to go through a few steps of radioactive decay so I'm talking about now a lot of radi different types of radio nuclear uranium thorium carbon nitrogen we actually have quite a lot of radioactive material in our environment that occur actually naturally most of them occur naturally one group of radioactive atoms we call them primordial these atoms were around when the solar system and the planets were formed these include uranium thorium and potassium so they were around what we find today they were around when the planet was formed I want to talk about potassium a little bit because all of us know about potassium potassium 40 is radioactive but potassium 39 is the stable one stable potassium has 19 protons and 20 neutrons that's the balance of proton neutron that makes it happy so a potassium with the number 39 that's the stable and out of every 10,000 potassium atoms we found in nature 99,999 are pottassium 39 but one in 10,000 has an extra Neutron which makes it potassium 40 and that is a radioactive potassium because it's a little bit unstable so it needs to get rid of that extra energy to become more stable now potassium 40 happens to be a patient atom because it takes it about a billion years to do that on average the half life of pottassium we'll talk about half life later but it takes it more than a billion years to go through that transition and become more stable atom now some of our Foods I'm sure many of you like bananas as you know banana is rich in potassium anything that has potassium it also has pottassium 40 because other of 10,000 atoms one of them is pottassium 40 so we have actually plenty of potassium 40 atoms right here in these bananas that we eat our bodies we have pottassium in our bodies and we have potassium 40 in our bodies and we we can actually measure the radiation that we emit because of that the other group of radio nucleid we have in our nature we call call them cosmogenic and that that means that when we have cosmic rays coming to us from outer space these cosmic rays interact with atoms we have in our environment particularly in our atmosphere and they create new species of radioactive material a good example we have plenty of nitrogen in our atmosphere and cosmic rays interact with nitrogen and make carbon 14 remember carbon 14 is a radioactive carbon carbon 12 is a stable one so carbon 14 is generated in our atmosphere when cosmic rays from outer space interact with nitrogen in our atmosphere and this carbon 14 over time becomes part of our nature Incorporated in our environment and become and becomes part of every organic life on Earth we all are carbon based that means we have carbon in fact one out of every trillion carbon atoms is a car radioactive carbon so we have carbon 14 in our bodies and anything else that's organic now you're familiar with carbon dating that's based on this principle the reason we can do carbon dating is because anything that has carbon in it uh we know has carbon 14 in it and we know the halflife and we can estimate the the approximate age of whatever it is that has carbon as part of it the last group of ride I want to talk about we call man-made we call them man-made because as the name implies man-made them they're through human activities that we have them in nature one example of that would be cesium 137 cesium 13 7 does not occur naturally in our environment it's actually byproduct of nuclear fision and the season 137 that we find in our environment are remnants of atmospheric testing of nuclear weapons in the 1950s and 60s CM 137 was part of that nuclear fallout and now we have it that has become part of our environment small amounts have become part of our environment we use this knowledge of how to produce um new species of radioactive material actually to our benefit too because many of the man-made radi nuclei we produce today are intentional because they have either applications in medicine industry or research another man-made source of radiation I should mention is those that are machine generated they don't come from radioactive materials they're machine generated and you all know about them x-ray machines and CT scanners in those machines there's no radioactivity but they use electricity to generate ionizing radiation so but once they generate those ionizing radiations have the same properties as the ionizing radiation that we get naturally from radioactive material but the generation is through a different mechanism and there's no radioactivity involved in there so now we're talking about lots of stuff lots of radioactive material lots of radiation coming from everywhere so the question how much are we getting from all of these sources what we call the amount of radiation is the dose and we measure it in units of merss in the United States an average person receives three Millers of radiation from natural sources from the cosmic rays the ground the food and everything 3 Mills of that three Mills 2/3 of it on average comes from radon radon is a radioactive gas that occurs naturally and has its origin actually to the uranium in soil the breakdown of uranium in soil so it's a naturally occurring radioactive material that is in form of gas so when I showed you earlier the balloon this is actually technically has radioactive materials in it because I exhaled in it when I blew the balloon I said and I exhaled every time we breathe we breathe in some radon uh and then I exhaled and some of those got trapped in the balloon so technically we do have radioactive atoms here in the air that we breathe and of course region to region place to place sometimes when we raid on home to home there's variation so we always have VAR ition in the amount of radiation we get from from natural environment but on average we get three Millers of radiation from the environment that's living on Earth on average we get another 3 MERS from medical procedures and a lot of us are getting X-ray exam or CT scans and so forth on average that contributes another 3 Millers 30 years ago that was less than one Millers but now it's close to 3 Millers because the technology has advanced so we're using that technology more so total on average three Millers from the environment and three Mills from medical exposures that gives us 6 Mills average annual dose to a person in the United States individual doses can vary so many factors can influence your individual dose if you smoke if you smoke the dose to your lung is actually quite significant radiation dose because of the radioactive material that's in tobacco so smoking increases your radiation dose to your lungs if you live at High elevation say Denver Colorado you get a higher dose from cosmic radiation than if you live near the coastline so where you live makes a difference if you share a bed with someone with your spouse or a partner remember our bodies contain radioactive material and we actually measure radiation coming out of our bodies we irradiate all the time so when you're sitting next to someone also you're irradiating each other so uh obviously those who share a bed that's a they get little extra radiation dose just because they don't sleep alone so these factors now that's a small factor but there are these other factors smoking high elevation and also other activities that would increase your individual dose in this chart you see some of the typical doses associated with some common activities like air travel chest x-rays CT scans in units of Millers compared to what we get from our natural background now the frequency of these activities like air travel or medical procedure would impact your total dose as an individual so even though our average is by 6 Millers as individuals your individual dose could vary and could be actually much higher in any given year now we talked about medical procedures and in the chart I showed you doses for medical procedures now this does not mean that we should avoid medical procedures like CT scans because they have a clear benefit for us doctors the Imaging studies provide valuable information to our doctors to make diagnosis so that's a clear benefit to us so it's important to consider the risks and benefits of any procedure or activity that exposes us to ionizing radiation [Music]