The DOE Ionizing Radiation Dose Ranges Chart
AU-22 001-2018December 2017The DOE Ionizing Radiation Dose Ranges ChartThe Ionizing Radiation Dose Ranges Chart wasdeveloped by the Department of Energy (DOE) andis used by the Office of the Associate UnderSecretary for Environment, Health, Safety andSecurity (AU) and various other DOE organizationsin presentations and radiation protection trainingactivities. This supporting document introducesradiation science and explains the Chart for thosenot completely familiar with the concepts itpresents.How does where you live affect yourexposure to radiation? Should you beconcerned about dental x-rays? Whatabout a CT scan?INTRODUCTIONRadiation is a normal part of our existence. Everyday each of us is exposed to radiation fromnaturally-occurring radionuclides in ourenvironment and in the foods we eat, as well asfrom cosmic radiation from space. Manyindividuals are exposed to additional radiationfrom medical diagnostics and procedures that canvary in dose by several orders of magnitude. Thenewly-revised DOE Ionizing Radiation Dose RangesChart puts this into perspective by comparingranges of doses from natural sources with dosesreceived occupationally or medically. The Chartattempts to provide a user-friendly reference forcomparison of radiation exposures of interest toscientists and the public, illustrating how ionizingradiation interacts with humans over six ordersof magnitude. This Information Brief will explainthe basic features and the arrangement of thesubject matter on the Chart. To begin, some basicradiation physics and radiation biology will bereviewed.RADIATION PHYSICSRadiation is the emission or transmission of energythrough a vacuum or through a material medium.Radiation broadly manifests in two forms:electromagnetic radiation (photons, e.g., heat,radio waves, microwaves, visible light, x-rays,gamma-rays), and particle radiation (e.g., alphaparticles, beta particles, neutrons, or heavy ions).Current scientific theory holds that all energeticparticles also have a wave nature, and that allelectromagnetic waves have a particulate nature;thus, light waves also behave as discreet packetsof energy, known as photons.Ionizing Radiation. Ionizing radiation is radiationthat carries sufficient energy to release one ormore electrons from their accustomed positions inatoms in matter through which it is traveling.Upon loss of one or more of its electrons, the atomis said to be ionized. The electrons and atoms mayimmediately recombine, and most do recombine,but if they do not then the atoms are left with apositive charge. An ionized atom or molecule maynow behave differently in matter. Ionizingradiation can be either electromagnetic waves(photons) on the high-energy end of theelectromagnetic spectrum (very high UV, X-rays,and gamma-rays), or energetic subatomicparticles, ions, and atoms moving at high speeds.Figure 1 illustrates the more common types ofionizing radiation. Alpha particles ( ) are ionizedhelium nuclei with a positive charge of 1 or 2; beta
particles ( ) are energeticfree electrons; gamma-rays( ) are high energy photonsemitted from an atomicnucleus; and neutrons (n0)are energetic neutralparticles emitted from thenucleus of atoms. Whenionizing radiation interactswith matter, secondaryradiations may be generatedin the energy depositionprocess. Depending on theprimary radiationcharacteristics, thesesecondary radiations caninclude Bremsstrahlung Xrays, electron delta-rays,neutron-capture gammarays, and/or recoil protons, among others. Muchmore information on energy transfer can be foundin the radiation physics/dosimetry literature.Naturally-occurring ionizing radiation is eitheremitted in the decay of radioactive elements orarrives here from the sun or from space.Ionizing radiation usually cannot be detected bythe human senses. An exception is the fact thatthe retina of the eye can detect the passage ofheavy charged particles such as cosmic rays, thusexplaining why light flashes are regularly seen byastronauts in space flight. Ionizing radiation is,however, easily detected by several types ofdetection instruments, including gaseousionization detectors, semiconductor detectors, andscintillation detectors.Radioactive Decay. Radioactive decay is thespontaneous release of energy (in the form of x- orgamma-rays, beta or alpha-particles, and/orneutrons) from an unstable atom. The vastmajority of atoms on the Earth are inherentlystable, but some arenaturally unstable orradioactive, and subjectto radioactive decay.Almost all productsemitted in radioactivedecay are ionizingbecause the energy ofradioactive decay istypically far higher thanthat requiredto ionize. Figure 1 alsolists examples of alpha-,beta-, gamma-, and/orneutron-emittingradioactive atoms.
Non-Ionizing Radiation. Non-ionizing radiationdoes not have enough energy to ionize the matterthrough which it travels. It is only capable at mostof exciting the electrons to vibrate faster, but notenough for them to escape; the energy impartedfalls short of the binding energy of the electron,and therefore does not change the chemistry ofthe parent atom. Non-ionizing radiation includesthe photons with energies at, or below, the middleultraviolet part of the electromagnetic spectrum,including visible light, infrared, microwaves, andradio waves. Different wave frequencies havebeen used for many decades in human inventionssuch as broadcast television, radio, and morerecently the cell phone. Figure 2 shows theextended electromagnetic spectrum to includeboth ionizing and non-ionizing photon radiation.(Note: Non-ionizing radiation is not included onthe Dose Ranges Chart.)RADIATION BIOLOGYIonizing radiation can also impart enough energy inbiological systems to release one or moreelectrons from their normal positions in atomswithin biomolecules. This ionization cansignificantly change the subsequent chemistry ofthe biomolecule, and can impact the subsequenthealth of the system. For example, if atoms thatmake up a DNAmolecule in a biologicalcell are ionized, thenone or more single ordouble-strand DNAbreaks may occur. If thecell survives but thebreaks are not repaired,or are repairedincorrectly, then thedamaged cell couldimpact the health of thetissue.Low Dose Exposures.The vast majority ofhuman exposure toradiation is in the lowdose range below 10 rem acutely delivered or 50rem chronically delivered, and for these smalldoses our natural protective defenses aregenerally more than adequate for a healthyindividual to resolve the damage. Even a severelydamaged cell in an otherwise healthy humantissue or organ will normally undergo cell deathand be replaced. Our protective mechanismsinclude DNA repair, cell death and replacement,immune system surveillance, and adaptiveresponse.High Dose Exposures. Conversely, if the radiationdose is high enough and the rate of exposure isalso high (acute exposure), then our protectivehomeostatic defenses will be damaged over a widearea and cannot operate efficiently, and may evenbe permanently compromised. Exposure to veryhigh doses of ionizing radiation, given at a fast rate(seconds to minutes) causes damage to livingtissue that may not be repaired. Depending on thetotal dose, high dose rate exposure can result inhigher risk of cancer over a lifetime, radiationsickness, or even death.Humans differ by age, gender, geneticpredisposition, state of health, etc., and will alsoshow variability in defending against the manyenvironmental stresses with which we live.
However, it is worth noting that in most studies ofhuman populations living in high backgroundradiation areas, no excess cancer rates or otherdisease rates have been measured (BEIR VIIReport, 2006). Likewise, public health data havenot established that cancer occurs at a higher ratefollowing exposure to low doses and dose rates —below about 10 rem (0.1 Sv) (NRC, 2017).MEASUREMENT OF DOSEThree different dose quantities of radiation (eithermeasured or calculated) are of importance fordiscussion of the Chart. They are “absorbed dose,”“equivalent dose,” and “effective dose.”At the present time there are two systems ofradiation units in normal use in the world. Theyare the conventional or traditional units ofrad/rem/curie, and the newer SystemInternationale (SI) units of gray/sievert/becquerel.Figure 3 shows the names of the units used ineach system. The United States uses mainly theconventional units, but is transitioning to SI units.Therefore, the Dose Ranges Chart has beenpublished in both systems of measure (rem andsievert).Absorbed Dose. As ionizing radiation passesthrough matter, some or all of its energy isabsorbed by the matter. The amount that isabsorbed is referred to as theabsorbed dose and themeasurement of this dose isgiven in rads or in grays (Gy).Absorbed dose is furtherexpressed in the fundamentalunits of energy per unit mass(or matter), such as ergs pergram (the rad) or joules perkilogram (the gray).Equivalent Dose. There arerelative differences betweenvarious types of radiation suchas x-rays and gamma-rays vs.neutrons, protons, alphaparticles, heavy ions, having todo with how each of themdeposits energy spatially in matter. Scientificcommittees have assigned a Radiation WeightingFactor for each radiation type based on measuredamounts of various radiations that would producean equivalent effect in matter. Thus, theequivalent dose is given by multiplying themeasured absorbed dose by the RadiationWeighting Factor. The resulting quantity is still inunits of energy per unit mass, now referred to asrem (the absorbed dose in rads multiplied byRadiation Weighting Factor) or sievert (theabsorbed dose in Gy multiplied by RadiationWeighting Factor). With the intent of emphasizingthe physics over the biology, the Dose RangesChart uses equivalent dose for most quantities,and absorbed dose for medical exposures.Effective Dose. There is a third importantradiation exposure quantity that is useful in someinstances, but is not used for the Dose RangesChart – the effective dose. Much research has alsobeen devoted to determining radiation sensitivitiesfor risk of cancer in the different tissues andorgans of the human body, and this informationhas been used to produce a list of Tissue WeightingFactors. Thus, in the case where there is only apartial-body irradiation, effective dose is calculatedby multiplying the equivalent dose by theappropriate Tissue Weighting Factor. This gives an
estimate of the dose to the whole individual thatwould effectively produce the same risk of cancer.Effective dose has the same unit names asequivalent dose—the rem or the Sievert (seeFigure 3).STRUCTURE OF THE CHARTThe general structure of the Dose Ranges Chart isshown in Figure 4, using the conventional(traditional) unit of the rem. Each of the axes arenumbered from one to six, for ease of discussion.Study each of the axes in turn. Notice that eachaxis is a linear scale, beginning with zero andending with a power of ten in units as designatedfor each axis. For example, the top axis, labelled 6in Figure 4, shows a dose range of from zero to10,000 rem. Compare the range from one axis tothe next, and notice that neighboring axes differ bya factor of ten (an order of magnitude). As can beseen by traveling from the topmost axisdownward, each succeeding lower axis comprisesa projection of the first 1/10th of the dose of itsneighbor axis above. Thus, the next axis down,labeled 5, has a dose range of from zero to 1,000rem. The blue colored shapes sweeping down toconnect the neighboring axes are designed toremind the reader of this relationship. Eachsucceeding lower axis expands and spreads out thefirst tenth of the upper axis so that the doseranges graphed within that order of magnitudecan be easily seen.Another way to picture the Chart structure is tostart at the lowest axis (number 1) and realize thatits entire range, from zero to 100 mrem, fits intothe first 1/10th of the axis above it (number 2). Inthe case of these two lower axes, some quantitiesare graphed on both of the axes—medical
diagnostics A and B, and also the “DOE, NRC doselimit for the public: 100 mrem/y.”sources of natural ionizing radiation on Earth andare referred to as background radiation.Figures 5 and 6 are the Dose Ranges Chart in remand sievert, respectively. The information can bemostly subdivided into several topics, which arecolor-coded for easier recognition: Natural Background Radiation is seen in greentext and arrows; Medical Diagnostics and Therapy are in blue; Acute Radiation Syndromes are in grey orblack; and Regulations and Guidelines are in red.Radioactive decay is the major source (89%) ofbackground radiation exposure. We receiveinternal exposures from radionuclides acquiredfrom food and water and from the radioactiveradon gas in the air. We receive external exposurefrom naturally-occurring radionuclides in the soil.Naturally-occurring radioactive elements in Earth’scrust of greatest importance are the uranium-238series, the thorium-232 series, and potassium-40(238U and 232Th series, and 40K). The significantradioactive elements taken into our bodiesthrough food and water are potassium-40, carbon14, and radium-226 (40K, 14C, 226Ra), while thosebreathed in from the air are radon-222 and radon220 (222Rn and 220Rn).NATURAL BACKGROUND RADIATIONEveryone on the planet is exposed to naturallyoccurring background radiation, thus it warrantsslightly longer discussion here. Cosmic rays andthe decay of radioactive elements are the primary
Space radiation (the other 11%) consists ofphotons, protons, and alpha particles from thesun, and cosmic rays from outer space. Cosmicrays are primarily very high-energy heavy ionsgenerated beyond our solar system by stars andcertain celestial events such as supernovaexplosions. Cosmic rays can produceradioisotopes in the atmosphere (e.g., carbon-14),which in turn decay and produce additional ionizingradiation. Other secondary cosmic rays that areproduced in the atmosphere include muons,mesons, positrons, and neutrons. Much of thebackground radiation found in interplanetary spaceis shielded from reaching the surface of Earth bythe Sun’s electromagnetic field, and the planet’satmosphere and electromagnetic field. The highera person travels in altitude from the surface, thegreater the dose received from space radiation. Asan example, the Dose Ranges Chart (Figures 5, 6)shows that a round-trip flight between Los Angelesand New York City adds an additional 3.7 mrem(0.037 mSv) to an individual’s exposure.In the United States, the average individual yearlynaturally-occurring background dose is 310 mremin a year (3.1 mSv/year), as recently evaluated bythe National Council on Radiation Protection andMeasurements (NCRP REPORT No. 160 (2009)Ionizing Radiation Exposure of the Population ofthe United States). This dose can be divided intofour types of exposure routes, each providingdistinct percent contributions of the total: 7% is external exposure from naturallyoccurring radionuclides in the soil; 11% is external exposure from space radiation; 9% is internal exposure from radionuclides inthe food and water we consume; and 73% is internal exposure from naturallyoccurring inhaled radon gas in the air webreathe.In addition to the average background dose in theUnited States, the Dose Ranges Chart also showsranges of several high background radiation areas(HBRAs) of interest, such as the Kerala Coast ofIndia with 1 to 6 rem/year annual dose (axisnumber 3), and the area around Ramsar, Iran,where annual doses are from 5 to 25 rem/year(axis number 4). Again, it is worth noting that inmost studies of human populations living in highbackground radiation areas, no excess cancer ratesor other disease rates have been measured (BEIRVII Report, 2006).MEDICAL USES OF RADIATIONSmall doses of x-rays or other radiations areroutinely used in medical diagnosis to visualizeinternal anatomy. High doses of radiation havealso been used for many decades in cancertherapy to shrink and kill tumors. The boxedinformation on the lower right side of the Chart(Figures 5, 6) lists medical diagnostic dosequantities as absorbed dose or organ dose,marked A through N, and graphed as letters on theChart itself. One fluoroscopic procedure (TIPS) isalso listed in the box and it is marked with theletter O on the Chart. Cancer radiotherapy doses(to the tumor) are much higher in dose thanfluoroscopic procedures, and range above 2000rads (20 Gy), shown on the highest axis (number6). Medical exposures are mostly x- or gammarays, and these have a Radiation Weighting Factorof one. Therefore, 1 rad is equal to 1 remequivalent dose, and 1 Gy is equal to 1 Svequivalent dose, thus allowing them to be graphedon the same Chart. Ionizing radiation for medicaluses is generated artificially using X-ray tubes orparticle accelerators, or by using a gammaemitting radioisotope (cobalt-60, for example) thatis built into a medical irradiation device.ACUTE RADIATION SYNDROMES (ARS)At the higher doses and rates of exposure,radiation can overwhelm the body’s ability torepair or replace damaged components in a timelymanner. Depending on the dose, dose rate, andextent of the body that is exposed, varioustemporary or permanent types of damage willoccur. As a group, the resulting symptoms aretermed Acute Radiation Syndrome (ARS),presented on axis number 5. [NOTE: The term“acute” in radiation science means that theexposure occurs in seconds to minutes, whereas
“chronic” exposure happens over days, months,years, or decades. Both acute and chronicexposures can be of varying amounts of dose.] ForARS, the damage ranges from a transient skinerythema (reddening of skin) within 2–24 hoursafter about 200 rem, to immediate death bycerebral/vascular breakdown after 9000 rem orgreater (whole body acute). Observation ofARS in irradiated individuals was the earliesttype of biodosimetry known; by looking at thecombination of symptoms of an exposed accidentvictim, it is possible to determine a rough estimateof radiation dose received. A lower dose of about45 rem acute may result in a transient increase inchromosome aberrations in the blood; this type ofbiodosimetry is used today for emergencyoccurrences when radiation detectormeasurements are not available.Axis number 5 shows two separate but overlappingLD50/30 dose ranges. This notation is defined asLethal Dose 50/30: the whole body acute dosethat results in lethality to 50% of an exposedpopulation within 30 days after irradiation. TheChart shows LD50/30 ranges for a human populationeither with or without medical intervention.REGULATIONS AND GUIDELINESAs presented in axis number 1, the Federalgovernment is responsible for setting bothoccupational and public radiation exposurestandards and limits in the United States. TheFederal agencies that have regulatory authority forradiation protection at different sites/facilitiesinclude DOE, EPA, NRC, DOD, DHS, DOT, HHS, andOSHA. The EPA and DHS also have establishedguidelines to be used in emergency situations.Several of these guidelines are graphed on theChart in axes number 3 and 4.THE CHART DISCLAIMERThe Chart was compiled under the auspices ofDOE, but please notice the disclaimer that isappended to the Note at the bottom of the Chart,part of which reads:“ Disclaimer: Neither the United StatesGovernment nor any agency thereof, nor anyof their employees, makes any warranty,express or implied, or assumes any legalliability or responsibility for the accuracy,completeness, or usefulness of anyinformation disclosed.”SELECTED REFERENCESAnno GH, Young RW, Bloom RM, and Mercier JR.Dose Response Relationships for Acute Ionizing –Radiation Lethality. Health Physics; 84: 565-575;2003.Hall, EJ and Giaccia, AJ. Radiobiology for theRadiologist, 7th edition. Lippincott Williams &Wilson, 2012.National Academies of Sciences, Engineering, andMedicine. Adopting the International System ofUnits for Radiation Measurements in the UnitedStates: Proceedings of a Workshop. Washington DC:The National Academies
Non-ionizing radiation includes the photons with energies at, or below, the middle ultraviolet part of the electromagnetic spectrum, including visible light, infrared, microwaves, and radio waves. Different wave frequencies have been used for many decades in human inventions
Ionizing radiation: Ionizing radiation is the highenergy radiation that - causes most of the concerns about radiation exposure during military service. Ionizing radiation contains enough energy to remove an electron (ionize) from an atom or molecule and to damage DNA in cells.
Ionizing & Non-Ionizing Radiation Interest in this area of potential human hazard stems, in part, from the magnitude of harm or damage that an individual who is exposed can experience. It is widely known that the risks associated with exposures to ionizing radiation are significantly greater than compa-rable exposures to non-ionizing radiation.
Non-ionizing radiation. Low frequency sources of non-ionizing radiation are not known to present health risks. High frequency sources of ionizing radiation (such as the sun and ultraviolet radiation) can cause burns and tissue damage with overexposure. 4. Does image and demonstration B represent the effects of non-ionizing or ionizing radiation?
May 02, 2018 · D. Program Evaluation ͟The organization has provided a description of the framework for how each program will be evaluated. The framework should include all the elements below: ͟The evaluation methods are cost-effective for the organization ͟Quantitative and qualitative data is being collected (at Basics tier, data collection must have begun)
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Non-Ionizing Radiation Non-ionizing radiation includes both low frequency radiation and moderately high frequency radiation, including radio waves, microwaves and infrared radiation, visible light, and lower frequency ultraviolet radiation. Non-ionizing radiation has enough energy to move around the atoms in a molecule or cause them to vibrate .
you about non-ionizing radiation, such as microwaves, ultrasound, or ultraviolet radiation. Exposure to ionizing radiation can come from many sources. You can learn when and where you may be exposed to sources of ionizing radiation in the exposure section below. One source of exposure is from hazardous waste sites that contain radioactive waste.
Ionizing radiation can be classified into two catego-ries: photons (X-radiation and gamma radiation) and particles (alpha and beta particles and neutrons). Five types or sources of ionizing radiation are listed in the Report on Carcinogens as known to be hu-man carcinogens, in four separate listings: X-radiation and gamma radiation .
