Radiation Safety Training Manual

Transcription

1 Principles of Radiation Protection Table of Contents I. Purpose... 3 II. Scope... 3 III. Procedures... 3 III.A. The Atom... 3 III.B. Radiation and Radioactivity... 5 III.B.1. Beta Radiation... 6 III.B.2. Alpha Radiation... 7 III.B.3. Gamma Radiation... 7 III.B.4. X-Ray Radiation... 8 III.B.5. Bremsstrahlung Radiation... 8 III.C. Sources of Radiation III.C.1. Natural Sources III.C.2. Man-Made Sources III.C.3. Exposure Categories III.D. Biological Effects III.D.1. Cell Damage III.D.2. Types of Effects III.D.3. Biological Factors III.D.4. Prenatal Exposure III.D.5. What is Known III.D.6. Risk III.E. Regulating the Use of Radioactive Material III.E.1. Occupational Exposure Limits: III.E.2. Exposure Limits to Minors III.E.3. Occupational Exposure Records III.E.4. Exposure Limits to Pregnant Employees III.E.5. Exposure Limits to the General Public III.E.6. Leak Testing Sealed Sources III.E.7. Monitoring Radiation III.E.8. Dosimetry Requirements III.E.9. Engineering Controls III.E.10. Posting Requirements III.F. Monitoring for Radiation and Contamination III.F.1. Survey Meters III.F.2. Dosimetry III.F.3. Wipe Test Procedures III.G. ALARA Exposure and Contamination Control April 2018 EHS-MAN

2 III.G.1. Time III.G.2. Distance III.G.3. Shielding III.H. Working Safely with Radioactive Material III.H.1. General Requirements III.H.2. Low Energy Beta Emitters III.H.3. High-Energy Beta Emitters III.H.4. X-Ray and Gamma Emitters III.I. Radioactive Waste Disposal III.I.1. Dry Solid Waste III.I.2. Liquid Waste III.I.3. Liquid Scintillation Vials III.I.4. Mixed Waste III.I.5. Animal Carcasses III.I.6. Biological Waste III.J. Emergency Procedures III.J.1. Minor Spills III.J.2. Major Spills III.J.3. Personal Contamination III.J.4. Accidents Involving Radioactive Dust, Mists, Fumes, Organic Vapors, and Gases: III.J.5. Injuries to Personnel Involving Radioactive Material: III.J.6. Unauthorized Removal, Theft, or Loss of Radioactive Material IV. Definitions V. Effective Date VI. Procedure Management and Responsibilities April 2018 EHS-MAN

3 I. Purpose This training manual provides the basics of radiation safety and points of information required for all Albert Einstein College of Medicine (Einstein) faculty, staff, and students who may work with or come into contact with radiation. II. Scope The procedures outlined herein apply to all Einstein faculty, staff, and students. III. III.A. Procedures The Atom The basic theory describes the atom as consisting of a central core composed of protons and neutrons surrounded by orbiting electrons. It is similar to the solar system in which the sun is at the center with the planets orbiting at various distances out. However, the electrons are orbiting at specific discreet distances and can be knocked out of their orbits by other particles. The atom is very small, in the order of a 1 x meters. The nucleus is even smaller with a diameter of about 1 x meters. Note that Figure 1 is not in proportion for the size of the nucleus to the atom. Figure 1: The Basic Structure of the Atom As stated above the nucleus is composed of protons and neutrons. A proton is a positively charged particle with a charge of 1.6 x coulombs and a mass of 1.7 x kilograms. The neutron is a particle without charge or electrically neutral and a mass of about 1.7 x kilograms. The protons and neutrons in the nucleus are bound tightly together by the strong nuclear force. However, if energy is added to the nucleus or it is unstable it can release particles or wave radiation in the form of beta, alpha particles or gamma radiation. Electrons orbit the nucleus in the atom and form orbital shells around it. They have a negative electrical charge of 1.6 x coulombs and a mass of 9.1 x kilograms. Because the electron has a negative charge it is attracted to the positive charge of protons. This helps keep it in its orbit about the nucleus. Electrons can jump from one orbital shell to another if it absorbs energy from another particle such as another electron. When it jumps to another orbital shell it leaves a hole into which another electron can fall. To do this the other electron would give up some energy in a wave form such as light, UV radiation or x-rays. 23 April 2018 EHS-MAN

4 While the atoms found commonly in nature are stable and do not spontaneously decay to other atoms, there are some atoms both natural and man-made that are unstable and decay to a more stable form. These atoms are considered radioactive and are called radioisotopes. Examples of unstable atoms found in nature are Tritium (H 3 ), Carbon-14 and Uranium-238. Unstable atoms are far more numerous than stable atoms. However, because they are so unstable and rapidly transform to stable isotopes, they are not commonly found in nature. Radioisotopes used for medical and research applications must be produced in an accelerator or nuclear reactor. If you were to plot the number of protons in each atom against the number of neutrons in the atom you would obtain the following curve, Figure 2: Figure 2: Graph of Proton Number versus Neutron Number for All Nuclides The black boxes represent stable atoms and forms the line of stability, while the other colors represent unstable atoms. The solid black line on the graph represents a curve for which the number of protons equals the number of neutrons. Note that the curve formed by the black dots begins at the black line but moves away from it as the number of protons increases. This results from the fact that greater number of neutrons than protons are required to have a stable atom. Otherwise the positive repulsive force between the protons in the nucleus would overcome the nuclear force holding it together, and the nucleus would break apart. If you move to the right or left of the line of stability you are in a region of unstable atoms. The further you move from that line the more unstable the atoms to the point where the atoms half-life is measured in times of less than a second (see section on half-life). Nuclear Stability: As indicated above, the atom consists of a nucleus containing protons and neutrons with a cloud of electrons orbiting the nucleus. The protons are positively charged while the electrons are negatively charged. For the atom to have a net neutral charge there must be an equal number of protons and electrons. For example, the helium atom contains 2 protons in its nucleus. To be electrically neutral, it must have 2 electrons orbiting the nucleus. 23 April 2018 EHS-MAN

5 Figure 3: Ionization of a Helium Atom If an atom has too many or too few electrons it is electrically charged and is said to be ionized. An electrically neutral atom can lose an electron if it interacts with radiation with sufficient energy to knock the electron out of the atom (see Figure 3). The process by which an atom loses one or more electrons is ionization and the space left behind is called an electron hole. The atom may later pick up an electron from its surroundings causing it to be electrically neutral and give off energy in the form of wave radiation. The radiation as we will see in the next chapter may be light, UV radiation, or x-rays, depending on which electrons are knocked out of the atom. If the radiation interacting with the atom does not have sufficient energy to knock an electron out of the atom it may just excite the electron in the atom. In this process the electron is knocked to a higher energy level or shell. At some point after that event the electron may drop back down into its original location giving up energy in the form of infrared or visible light. III.B. Radiation and Radioactivity Radioactivity is the process by which an unstable atom releases energy to become more stable. It may be said that radioactive atoms go through a process of radioactive decay to increase its stability. Energy is released through radiation in the form of waves or particles. In most cases the release of energy is from the nucleus of the atom, but in some cases, it can be released from the electron shells adjacent to the nucleus. Wave Radiation: Radiation can be divided into two types of radiation, ionizing and non-ionizing. It was shown in Module 1 that energy can be released to the atom from radiation coming in close proximity to the atom causing the removal of an electron, ionization. Not all wave radiation has the energy to remove an electron from the atom s shell. Wave radiations that can cause ionization are gamma radiation, x-radiation, and ultraviolet radiation which have shorter wavelengths (see Figure 4). The other radiation, visible light, infrared, radio waves, and microwaves are all forms of non-ionizing radiation. These radiations only have enough energy to cause excitation of the atom. 23 April 2018 EHS-MAN

6 Figure 4: Electromagnetic Spectrum Another form of radiation, particulate radiation, can also originate from either the nucleus or the atom. However, in most cases it originates from the nucleus as with beta radiation and alpha radiation. For a few atoms the particle may be an electron ejected from the electron shells in close proximity to the nucleus. In this case the energy from the nucleus is transferred to the electron. Particulate Radiation: An unstable atom may achieve a more stable state by ejecting part of the nucleus during radioactive decay. III.B.1. Beta Radiation Radioactive material emitting beta radiation is the most frequently used in biomedical research. Beta radiation is a particulate form of radiation that originates in the nucleus. It is formed by the transformation of a neutron in the nucleus to a proton, ultimately making the nucleus more stable. The beta particle is nothing more than a negatively charged electron traveling at about 98% the speed of light. The energy of the electron ranges from a few thousand electron volts (KeV) to millions of electron volts (MeV). The energy of the electron determines how deeply penetrating the electron is in matter or the human body. The more energetic the electron the more penetrating it is. For example, beta particles from Tritium (H 3 ) have low energies, about 18 KeV, and are not very penetrating. However, Phosphorus-32 (P 32 ) emits very high energetic beta particles, about 1.7 MeV which are very penetrating. Table 1 lists some common beta emitting radioisotopes used in biomedical research. 23 April 2018 EHS-MAN

7 Table 1: Typical Beta Emitting Radionuclides Name Symbol Maximum Energy (MeV) Shielding Required Tritium H No Carbon-14 C No Sulfur-35 S No Phosphorus-33 P No Calcium-45 Ca No Phosphorous-32 P Yes III.B.2. Alpha Radiation While radioactive material that emits alpha radiation is not commonly used in research laboratories, it can be commonly found in nature. Alpha radiation is another form of particulate radiation. An alpha particle consists of two protons and two neutrons and travel at high speeds. Alpha particles usually have energies ranging from 1 to 10 MeV. You would think that an alpha particle would be very penetrating with such high energies. However, because the alpha particle is so much larger than a beta particle, over 4000 times, it is not very penetrating. This massive particle readily interacts with atoms in matter and quickly slows down before it has a chance to penetrate a material. Therefore, alpha particles can be stopped by a sheet of paper. A common example of an alpha emitter is Radon, which frequently comes up as a possible health hazard when present in large quantities in homes. When Radon decays to a more stable atom it emits an alpha particle. Because the alpha particle is not very penetrating it is not considered an external radiation hazard. This is because it will be stopped by the dead layer of skin on the surface of the human body. However, because it is airborne and can be inhaled by an individual, it can be an internal radiation hazard. If radon decays while in the lungs it gives off alpha particles which can strike the lung tissue and cause damage. III.B.3. Gamma Radiation Gamma radiation is a wave form of radiation traveling at the speed of light. The distinction between x- rays and gamma rays is that the source x-ray radiation originates from the atomic shell and results from electrons in the shell dropping to the lower shells. Gamma radiation originates from within the nucleus and results from neutrons and protons dropping to more stable positions inside the nucleus and coincides with the decay of unstable atoms. They are very penetrating and can readily pass through many materials. The ability to penetrate materials also depends on the energy of the gamma ray, which ranges from around 0.5 MeV up to 3.0 MeV. The most effective materials used for shielding gamma radiation have high densities, such as lead and uranium. Lead is commonly used for shielding as it is a dense, cheap, readily available material. The amount of lead used for shielding depends on the energy and amount of radiation emitted by a source. 23 April 2018 EHS-MAN

8 III.B.4. X-Ray Radiation X-rays are emitted from the inner shell electrons of the atom. This occurs when an electron drops down to a lower shell that is missing an electron, which can be described as having a hole" where the electron used to be. The lower shell may be missing an electron for two reasons. It may have been knocked out of the atom when energy from the unstable nucleus was transferred to it and the electron obtained energy by absorbing a gamma ray, a process known as internal conversion. The second possibility is that an electron may have been captured by the nucleus thus leaving a hole for another electron to drop into. When the electron is captured by the nucleus, it combines with a proton to form a neutron. This is called electron capture. X-ray radiation is a wave radiation that travels at the speed of light. The x-rays= energy range from a few KeV to many MeV and is also a very penetrating radiation. The ability to penetrate again depends on the energy of the x-ray. Table 2 lists some common radioisotopes that emit gamma and x-rays. Table 2: Typical Gamma and X-ray Emitters Name Symbol Energy in MeV Shielding Required Chromium-51 Cr gamma Yes Iodine-125 I gamma, x-ray Yes Iodine-131 I gamma Yes Technicum-99m Tc 99m 0.14 gamma, x-ray Yes The shielding of choice for x-rays is also lead, which as with gamma radiation the amount used for shielding depends on the energy and the activity of the source. Figure 5: Lead bricks or sheets may be used as shielding for gamma and x-rays. III.B.5. Bremsstrahlung Radiation X-rays occur when high energy beta radiation strikes dense material such as lead. When a negatively charged high-speed electron interacts with the positive electric field surrounding a nucleus, it quickly accelerates toward it. The rapid acceleration and sudden change of direction results in the release of an x- ray. This is the process used in x-ray machines where electrons are stripped from a surface and 23 April 2018 EHS-MAN

9 accelerated toward a metal plate. When the electrons strike the plate they rapidly decelerate generating x- rays in the process. The x-rays are focused into a beam that is used to form the image on the film. These x-rays are given the name Bremsstrahlung (braking) radiation because the kinetic energy of the electron is transferred to the creation of the x-ray which results in it slowing down. Bremsstrahlung radiation may be a source of exposure for individuals working with P 32. Figure 6: A Plexiglas Shield use for work with P-32 Measuring Radioactivity and Radiation: Specific units were established to quantify radioactive material. The units describe the rate at which the radioactive material is decaying or transforming to another material. The first such unit was the Curie, named after Marie Curie who discovered and worked with radium. The unit was originally defined as the disintegration rate for any radioactive sample that undergoes the same number of disintegrations per unit time as that for 1 gram of pure Radium-226. It was later defined as the quantity of any radionuclide in which the number of disintegrations per second is 3.7 x Because the Curie is a rather large quantity, we use smaller units to express the quantity of material. Subunits of the Curie that are frequently used are the microcurie (uci) and the millicurie (mci), which are 10-6 and a 10-3 Curies respectively. Finally, the International Scientific Unit for radioactive material is the Becquerel (Bq) and is defined as one disintegration per second (dps). 1 Curie = 3.7 x dps = 2.22 x dpm = 3.7 x Bq 1 mci = 3.7 x 10 7 dps = 2.22 x 10 9 dpm 1 uci = 3.7 x 10 4 dps = 2.22 x 10 6 dpm where dpm stands for disintegrations per minute. As an example, consider 250 uci of P 32. This would be Ci or 0.25 mci or 9.25 x 10 6 dps or 9.25 x 10 6 Bq or 5.55 x 10 8 dpm. 23 April 2018 EHS-MAN

10 The next units that need to be addressed are those related to radiation exposure. These are quantities that describe how much radiation is present at a time and distance from a particular source of radioactive material. The first unit established for quantifying radiation exposure was the Roentgen. It was defined as the amount of radiation that generated a charge of 2.58 x 10 4 coulombs per kilogram of air. That is, if you had a volume of air equal to 1 kilogram and exposed it to 1 Roentgen of gamma or x-rays it would generate a charge in the air equal to 2.58 x 10 4 coulombs. To determine the amount of energy imparted to matter, a unit called the Radiation Absorbed Dose (Rad) was defined. One Rad is equal to 6.24 x 10 7 MeV per gram of material. What this means is that if you have a gram of anything and you apply 1 Rad of any radiation, the energy absorbed by the material will be equal to 6.24 x 10 7 MeV. This is a relatively large exposure so a subunit of the Rad called the millirad (mrad), which is 1000 Rads, is more commonly used. The international unit of measurement for absorbed dose is the gray, where 1 Gray equals 100 Rads. Finally, to provide a quantitative description of exposure in terms of biological effects to humans the Rem was developed. Rem stands for roentgen equivalent man and is related to the absorbed dose in units of Rads by the equation: Rem = (Rad) (QF) (DF) where QF is a quality factor which depends on the type of radiation being measured and DF is the distribution factor which typically has a value of one if the radiation field is perfectly uniform. Table 3: Quality Factor (QF) Values for Various Types of Radiation Radiation QF X-rays, gamma rays, electrons, beta radiation 1 Thermal Neutrons 5 Fast neutrons, protons, alpha radiation, heavy ions 20 Note that the quality factor for beta, x-ray and gamma radiation is one, which says that the dose equivalent in Rem is equal to the absorbed dose in Rads. The international unit for the dose equivalent is the Sievert, which is equal to 100 Rem. The Half Life of a Radioactive Material: When radioactive material decays it does so at a specific rate defined as its half-life. The radioactive half-life is the time it takes a radioactive material to decay to half of its original amount. For example, P 32 has a half-life of 14.3 days. Therefore, if you received 250 uci of P 32 on October 1 st and measured the activity 14.3 days later you would have only 125 uci. If you measured it again 14.3 days from the first measurement, you would have only 62.5 uci. If you held the material for 10 half-lives or 147 days, you would have only 0.24 uci of P 32 left. This can be easily calculated by the formula: 23 April 2018 EHS-MAN

11 [Activity = Act 0/2 n ], where Act 0 is the original activity of the material and n is the number of half-lives after the date of the original activity. For the example above: Activity = 250/2 10 = 250/1025 = 0.24 uci Another method of calculating the activity after a time, is to use the equation: [Activity = Act 0 x exp( x t/t 1/2)], where Act 0 is the original activity of the material, t is the time since the date of the original activity, and t 1/2 is the half-life for the radioactive material. As an example, consider A 0-1 mci for P 32, which has a half-life of t 1/2 = 14.3 days. If you measure the activity 10 days later the amount of material remaining will be: Activity = (1 mci) x exp( x 10/14.3) = 0.62 mci Table 4: Natural Radioisotopes and Radioisotopes Used in Research and Their Respective Half Lives Radioisotope Uranium-238 Radon-222 C-14* H-3* P-32* S-35* I-125* Cr-51* Half Life 3,400,000,000 years 3.83 days 5,730 years 12.3 years 14.3 days 87.4 days 59.6 days 27.7 days The half-life of a radioactive material is a finger print for that material and can be used to identify a radioisotope. Half-lives range from nanoseconds to billions of years. Those radioisotopes with very short half-lives reveal their existence through the isotopes left behind after they decay. Uranium-238 has gone through roughly one half-life since the formation of the earth. So only half of the original amount of uranium is presently on the earth. III.C. Sources of Radiation There are two sources of radiation in the world; environmental and man-made. Prior to man-made sources, all an individual s exposure was from the environmental sources in the world. However, while most of the radiation exposure to an individual is still environmental, a large portion of that exposure is from man-made sources. III.C.1. Natural Sources The sources of radiation naturally occurring in the environment are cosmic radiation, radioactive material in rocks, radon in homes, and naturally occurring radioactive material in humans. Cosmic radiation 23 April 2018 EHS-MAN

12 originates from the sun and outside the solar system. The earth is constantly bombarded with cosmic rays that can penetrate to the surface of the earth and strike an individual or interact with molecules in the atmosphere creating radioactive atoms. The amount of cosmic radiation coming from the sun depends on processes occurring within the sun and which fluctuate over an 11-year cycle. The average annual exposure from cosmic radiation is about 30 mrem. Radioactive material in rocks and soil include uranium, thorium, and radium. These naturally occurring radioisotopes are found in carnotite, uranophane, tribanite, pitchblende and other rocks. Figure 7: Carnotite in Petrified Wood There is a beach in Brazil where the sand contains large amounts of thorium. So, if you lay out on that beach to get a tan, you will also receive an exposure of 10 mrem/hr. The average exposure from radioactive material in rocks and soil is 20 mrem per year. Radon, a radioactive gas, is a byproduct of the radioactive decay of radium. Radium is a naturally occurring radioisotope that is found in small quantities in rocks. When radium decays to radon, the radon is released from the rock as a gas into the atmosphere. If a house is built over the rock, the radon can diffuse into the house through cracks in the basement floor and walls. It can build up inside the house and create a potential exposure hazard to individuals living in the house. As will be discussed later in the training, exposure from radon is an internal hazard. When radon is inhaled by occupants of an affected house it can decay inside the lung giving off an alpha particle which imbeds in the lung tissue and causes damage. Radon in homes is a significant source of radiation in this country and contributes to an annual average exposure of 230 mrem. Figure 8: Radon can emanate from the soil into houses 23 April 2018 EHS-MAN

13 Finally, you can fine small amounts of the naturally occurring radioactive material Potassium-40 in the human body. While it is not significant and makes up less than 1% of the total potassium in the human body, it contributes an average exposure of 39 mrem per year. The total average annual exposure from man-made and natural sources of radiation is 620 mrem (see Table 5). III.C.2. Man-Made Sources Exposure to manmade sources of radiation also contributes to the background dose. Some of these sources include medical exposures and consumer products. The average annual exposure to the general public from diagnostic x-rays such as a chest x-ray is 2.0 mrem; a mammogram is approximately 300 mrem. The average annual exposure in a nuclear medicine procedure where a radioactive tracer is injected into the patient for diagnosing cancer is 14 mrem. Significantly higher exposure of around 580 mrem can be received from receiving a chest computed tomography (CT) scan. Consumer products include a wide variety of products and devices, such as smoke detectors, tobacco products, natural gas, domestic water supplies, building material and airport baggage inspection systems. Common consumer products containing a radioactive source that should be found in every home are smoke detectors. They contain a few microcuries of Americium-241 in an ionization chamber which is used to detect smoke. Figure 9: Smoke Detectors contain a small amount of Am-241 The dinner ware, Fiestaware, was originally manufactured in the 1940's and 50's. The orange Fiestaware got its color from a paint containing uranium oxide. As a result of the radioactive uranium in the glaze, the orange Fiestaware is radioactive and can give off dose rates of up to 15 mrem per hour. Figure 10: Orange-red Fiestaware contains Uranium Oxide 23 April 2018 EHS-MAN

14 All these consumer product sources contribute a small amount of exposure to the general public, about 13 mrem per year. Table 5: Average Annual Exposure in the United States from Ionizing Radiation Source Dose in mrem Type of Exposure Cosmic 30 Natural Terrestrial 20 Natural Radon 230 Natural In the Body 40 Natural Medical 300 Man-Made Consumer Products 10 Man-Made Total Exposure 620 If you were to convert these numbers to a percentage of the total average annual exposure and plot the percentages on a pie-chart, you would have Figure 11. Note that the majority of the exposure is from medical exposures from diagnostic procedures and treatment. Radon is the second highest source of radiation; it was only recently discovered in the 1970's. The other sources, which are all natural, make up just fewer than 13% of the total exposure. Figure 11: Percentage of Average Annual Exposure to the General Public in the U.S. 23 April 2018 EHS-MAN

15 III.C.3. Exposure Categories Exposure can be divided into two categories; occupational and non-occupational exposure. Occupational exposure is exposure to radiation that is received while performing duties as an employee. It can be from working in a medical research institution, a hospital, or working in a nuclear power plant. Exposures from environmental sources of radiation are considered non-occupational exposures. However, exposures from man-made sources can be considered either occupational or non-occupational. For the individuals working with radioactive sources it is occupational, while for the general public exposed to the same radiation it is non-occupational. There are limits imposed on radiation exposure from some man-made sources of radiation, including exposure to the general public from radiation sources in hospitals, nuclear power plants and medical research institutions. There are also limits on exposure to individuals who are occupationally exposed to radiation. There are no regulations for exposure to environmental radiation; however, there are guidelines for safe levels of radon in homes. III.D. Biological Effects Most of the data available on the biological effects of radiation exposure comes from the early research on radiation sources by scientists. Other sources of exposure information include the early use of radiation producing devices by medical professionals, the atomic bomb victims in Japan, and accidents involving radiation sources. All these cases involved individuals exposed to significant amounts of radiation, greater than 50 Rads, over a short period of time. Exposures to individuals working in nuclear power plants, hospitals, or research institutions are of smaller magnitudes than those cited above. All occupational exposures to radiation are limited to a specific maximum amount as required by city, state or federal regulations. The effects described below are based on individuals receiving large exposures that are well above the regulatory limits. III.D.1. Cell Damage Radiation damages cells by breaking the DNA bonds within the cell. There are two possible mechanisms by which radiation can damage the DNA in cells; chemical reaction and physical reaction. The chemical reaction occurs when radiation interacts with water molecules resulting in the generation of peroxides in the vicinity of DNA. The peroxides attack the DNA by breaking bonds. This is an example of an indirect effect of radiation damage on cells. Mechanical damage to DNA occurs when the radiation physically strikes the DNA and breaks the bonds. The process by which the DNA in the cell is damaged by radiation takes about seconds. Biological effects result from the exposure of living organisms to ionizing radiation. The effects are dependent on the type and amount of radiation the organism is exposed to and the duration of the exposure. For example, if an organism is exposed to 200 Rads of beta radiation the effects will be different than if it were exposed to 200 Rads of gamma radiation. If the individual only received 1 Rad the effects would not be immediately observable, whereas if the individual received 200 Rads he/she would experience effects in a matter of hours. Additionally, if that same exposure of 200 Rads were spread out over 10 years, the effects would not be as serious as if the individual received the exposure over 1 hour. 23 April 2018 EHS-MAN

16 III.D.2. Types of Effects Biological effects can be categorized as acute effects or chronic effects. Acute effects are those that are immediately observable after exposure to large amounts of ionizing radiation over a short period of time. The amount of radiation exposure must be significant to produce acute effects, on the order of 100's of Rads exposure. These types of exposure are not to be expected at a medical research institution using microcurie and millicurie quantities of radioactive material. Acute effects have never occurred in nuclear power plants in the United States because of the strict requirements regarding operation and safety. However, the levels of radiation in some areas of nuclear power plants could cause this type of exposure. Acute exposures may occur with patient treatments in hospitals where individuals receive significant exposures. The observed acute effect depends on the dose to the individual. The effects on the body are so damaging that they overwhelm the ability of the body to repair or replace the cells fast enough. Whole body exposure to large amounts of radiation will cause radiation sickness, which may include the following symptoms; nausea, vomiting, diarrhea, fatigue, fever, loss of hair, blood changes, lethargy, and convulsions. The syndromes can be divided into three categories; central nervous system, gastrointestinal and hemopoietic syndromes. Skin erythema (reddening of the skin) occurs after doses of about 300 Rads. In addition, blistering, pigment changes, loss of hair, and necrosis due to infection are other possible skin effects. Much of the information we have on acute effects of radiation come from 4 groups of individuals exposed to significant levels of radiation: Those individuals working with radioactive material and radiation producing devices when it was first discovered, such as researchers and radiologist who received large doses of radiation before the biological effects were recognized. The victims of the atomic bombs dropped at Hiroshima and Nagasaki who received an estimated dose of 50 Rem. Individuals involved in radiation accidents such as that occurring at Chernobyl. Individuals who were treated as patients undergoing radiation therapy for cancer. Chronic effects are those effects that occur sometime after the exposure and include cancer, cataracts, and genetic effects. The normal chance of dying from cancer is about one in five (20%) for persons who have not received any occupational radiation dose. The chance of getting cancer from 1 Rem of radiation is 4 in 10,000. This means that a 1-rem (0.01 Sv) dose may increase an individual workers chance of dying from cancer from 20 percent to percent. Considering that most researchers will never receive 1 Rem of exposure during their lifetime, the chances of having cancer as a result of working with radioactive material is extremely small. Genetic effects are those effects that are passed on to the offspring of the individual exposed. The individual has experienced damage to some genetic material in the cell that, although it does not affect the individual, could potentially affect future generations. 23 April 2018 EHS-MAN

17 The data we have on chronic effects from radiation come from the same sources as that for acute effects along with years of low level radiation exposure to nuclear power plant workers. III.D.3. Biological Factors As indicated above, factors affecting the biological damage due to radiation exposure include the total dose, dose rate, and type of radiation. In addition, the area of the body exposed, the cell sensitivity and the individual sensitivity are important when considering the biological damage from radiation exposure. For example, if the whole body is exposed to 500 Rem of radiation it is likely that the individual will die from acute radiation symptoms if he/she does not receive medical care. However, if only the hand is exposed to the 500 Rems, the individual may experience radiation burns. Cell sensitivity to radiation, radio sensitivity, depends on how rapidly a particular group of cells are dividing. Red bone marrow, which divides rapidly relative to other cells in the body, is an example of radiosensitive cells in the body, while cells in the muscle, which are less radiosensitive, require more radiation to cause similar damage. Table 6 lists various cells and their grouping for radio sensitivity, where Group 1 are the most radiosensitive and Group 8 the least radiosensitive. Table 6: Radio Sensitivity of Mammalian Cells Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 III.D.4. Mature lymphocytes, erythroblasts and spermatogonia Granulosa cells, intestinal crypt cells and germinal cells of the epidermal layer of the skin Gastric gland cells and endothelial cells of the small blood vessels Osteoblast, osteoclasts, chondroblasts, granulosa cells of primitive ovarian follicles, spermatocytes and spermatids Granulocytes, osteocytes, sperm and superficial cells of the gastrointestinal tract Parenchymal and duct cells of glands, fibroblast, endothelial cells of large blood vessels, and erythrocytes Fibrocytes, reticular cells, chondrocytes and phagocytes Muscle cells and nerve cells Prenatal Exposure Prenatal exposure to radiation must be considered with female radiation workers. Like the radiosensitive cells described in section 4.3, the embryo/fetus is rapidly developing which makes it more sensitive to radiation exposure. The data used to determine radio sensitivity came from prenatal exposure from the atomic bomb used in Japan. Children who were exposed during pregnancy to radiation from the atomic bomb were born with low birth weights and mental retardation. It has been estimated that 1 Rem of exposure may increase the likelihood of birth defects by a factor of 1 in 1,000. However, the chances of receiving this amount of exposure in a medical research institution is extremely unlikely. The average whole-body exposure to an individual working in a research laboratory tends to be in the order of less than 5 mrem per year. Much of the exposure tends to be to the hands from working with P 32 which would have no effect on the embryo/fetus. 23 April 2018 EHS-MAN

18 While the risk is small, the federal government has set lower limits of exposure for occupational exposure to pregnant individuals. These limits will be discussed further in the regulatory modular. III.D.5. What is Known As stated earlier, all of the information we have on radiation exposure and resulting effects comes from exposure to large amounts of radiation, greater than 50 Rem. We do not know the effects of exposure to low levels of radiation. Though, as we saw in the sources modular, we are constantly exposed to small amounts of environmental radiation daily. All we can say for sure is that: No increases in cancer have been observed in individuals exposed to radiation in an occupational setting. The possibility of radiation exposure induced cancer cannot be totally dismissed. Risk calculations for low level exposure are based on the extrapolation of data resulting from high levels of exposure. III.D.6. Risk In considering the risk of exposure to radiation it may be helpful to compare the risk with other risks, including those from daily activities and those from other occupations. The following is intended to put the risk of radiation exposure into perspective when compared to other risks in life. From Table 7, it can be seen that the risk of exposure to 300 mrem/year of radiation for 47 years is low compared with other daily activities such as cigarette smoking or consuming alcohol. Even if the exposure was 1 Rem per year for 47 years it would not be comparable with most of the activities listed in the table. The values for Tables 7 and 8 were taken from the NRC Regulatory Guide Health Risk Smoking 20 cigarettes a day Table 7: Average Life Lost Due to Specific Activities 15% Overweight 2 Years Alcohol consumption (US average) Occupational Radiation Exposure (300 mrem/year from 18 to 65) Occupational Radiation Exposure (1000 mrem/year from 18 to 65) Medical Radiation Average Estimated Days Lost 6 Years 1 Year 15 Days 51 Days 6 Days Exposure to the legal limit for radiation of 1,000 mrem/year for 47 years is comparable with such occupations in government and mining. However, for most individuals working in a medical research setting, the actual exposure is significantly smaller (less than 50 mrem/year). 23 April 2018 EHS-MAN

19 Occupation Table 8: Estimated Reduction in Life Expectancy for Specific Occupation Agriculture 320 Construction 227 Mining and Quarrying 167 Transportation/Utilities 160 Government 60 Radiation Worker (1 Rem/Year) 51 Manufacturing 40 Service 27 Trade 27 Reduction in Life Expectancy (days) While exposure to radiation represents a risk, the risk is relatively small as the amount of material used in research is small. When compared with other potential sources of risk in everyday life and the workplace, the risk from radiation is negligible. When radioactive material is handled in a safe manner by following standard practices and procedures, the risk is further reduced. III.E. Regulating the Use of Radioactive Material There are a number of agencies that control the use of radioactive materials in the United States. The main agency is the Federal Nuclear Regulatory Commission (NRC). The NRC defines the rules and regulations for the use of radioactive material in the United States. However, in some cases the NRC may give the authority to control the use or radioactive material within a state to that state s government. This arrangement creates what is called an agreement state. For example, the State of New York is an agreement state because it controls the use of radioactive material within its borders. To complicate this even further, the City of New York is given the responsibility to control the use of radioactive material in medical institutions within the city while New York State controls industrial uses of radioactivity in the City and State. The Albert Einstein College of Medicine (Einstein) is licensed to use radioactive material through the NYC Department of Health and is obligated to follow those regulations set forth in The Rules of the City of New York, Title IV, Article 175". These rules are based on the Federal NRC regulations, 10CFR20. Einstein must renew and amend its license periodically and the City conducts routine inspections of activities under the license. A copy of the license is on file in the Department of Environmental Health and Safety for review. 23 April 2018 EHS-MAN

20 Figure 12: The City of New York Health Code, Part B, Article 175 The control and monitoring of radioactive material within the Einstein community is the responsibility of the Radiation Safety Committee. The committee consists of a Chairman, faculty who use radioactive material, administrators and the Radiation Safety Officer. It meets every 3 months to review the radiation safety program and discuss issues presented by the Radiation Safety Officer. The Radiation Safety Officer (RSO), who is a member of the Department of Environmental Health and Safety, is responsible for overseeing the day-to-day activities involving radioactive materials in research. The RSO provides guidance to users, conducts periodic inspections, approves the use of radioactive material, approves and monitors incoming packages of material, and manages the radioactive waste program. The RSO reviews quarterly inspection reports of approximately 120 laboratories. The inspections including the review of inventory records, wipe test records and a contamination survey of the laboratory. If an individual wishes to obtain information on the policies and requirements for the use of radioactive material at Einstein, they may refer to the Radiation Safety Manual. A copy of the manual should be available in each laboratory where radioactive materials are used. Copies can be obtained through the Department of Environmental Health and Safety (x2243). Figure 13: The Albert Einstein College of Medicine Radiation Safety Manual A Principal Investigator (PI) wishing to use radioactive material in their research must apply for a license through the RSO. This application process consists of completing a Radioactive Materials License Application form and attaching required documentation. The request is reviewed by the RSO and is distributed to the members of the Radiation Safety Committee for review and consideration of approval. 23 April 2018 EHS-MAN

21 If the license is approved by the committee, the PI is sent a memo granting him/her a license to use radioactive material. This license is renewable every 3 years. Ultimately, the licensed PI is responsible for the safe use of radioactive materials within their laboratory and ensuring that all required activities are performed. However, it is also the responsibility of the users to be familiar with the rules and regulations governing the use of material and appropriate laboratory practices. The following are applicable regulations governing the use of radioactive material and radiation producing devices at The Albert Einstein College of Medicine. For additional information, refer to the Rules of the City of New York, the Health Code, Part B, Article 175. (Copies can be obtained from Radiation Safety at x2243. III.E.1. Occupational Exposure Limits: The annual occupational dose to any individual shall not exceed the following: A total effective dose equivalent to the whole body of 5 Rem. The sum of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue of 50 Rem. An eye dose equivalent of 15 Rem. A skin or extremity dose equivalent of 50 Rem. While occupational exposures at medical research institutions are negligible, the possibility exists that an exposure could occur. Although it is not required, all research staff, custodial service and certain engineering staff, mail room and receiving staff may request a personal dosimeter. Exposures may occur to the hands of individuals working with large quantities of P 32, I 125, or any other isotope posing an external exposure risk. This results from the researcher s hands being in close proximity to the stock containers. For this reason, a ring dosimeter may be required for some research experiments. III.E.2. Exposure Limits to Minors The annual occupational dose to minors is limited to 10% of the occupational dose for adult workers listed in section III.E.1. A total effective dose equivalent to the whole body of 0.5 Rem. The sum of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue of 5 Rem. An eye dose equivalent of 1.5 Rem. A skin or extremity dose equivalent of 5 Rem. Typically, minors should not work with radioactive material. However, if it is absolutely necessary that they do, the individual should be monitored for radiation exposure monthly rather than quarterly. 23 April 2018 EHS-MAN

22 III.E.3. Occupational Exposure Records For each individual who may enter the licensee s or registrant s restricted area and is likely to receive, in a year, an occupational dose requiring monitoring (10% of exposure limits), the licensee or registrant shall: Determine the occupational radiation dose received during the current year. Request, in writing, the records of lifetime cumulative occupational radiation dose. Individuals applying for a badge who have documented exposure at another institution must sign a form authorizing the release of exposure records to The Albert Einstein College of Medicine. III.E.4. Exposure Limits to Pregnant Employees The dose to the embryo/fetus during the term of the pregnancy shall not exceed 500 mrem due to occupational exposure limits for a declared pregnant employee. The licensee shall review exposure history and adjust worker conditions to ensure that the monthly dose to a declared pregnant employee does not exceed 50 mrem. The dose to the embryo/fetus shall be the sum of the deep dose equivalent to the pregnant employee and the dose to the embryo/fetus from radionuclides in the embryo/fetus and radionuclides in the declared pregnant employee. If by the time the employee declares pregnancy to the licensee the dose to the embryo/fetus has exceeded 450 mrem, the licensee shall be deemed in compliance with the Code if the additional dose to the embryo/fetus does not exceed 50 mrem during the remainder of the pregnancy. A researcher who suspects or knows she is pregnant should request a fetal badge from Radiation safety. To obtain this badge a written declaration discussed with the Radiation Safety Officer is necessary and a review of risks. This includes researchers who work with radioactive material and those who work in radioisotope laboratories. Radiation Safety will issue the individual a monthly badge to track fetal exposure for the term of the pregnancy. III.E.5. Exposure Limits to the General Public The total effective dose equivalent to individual members of the public shall not exceed 100 mrem in a year. In addition, the dose in any unrestricted area from external sources shall not exceed 2 mrem in any one hour. These exposure limits apply to any individual not affiliated with Einstein who enters a laboratory; for example, vendors, visitors, or relatives. III.E.6. Leak Testing Sealed Sources All beta/gamma and neutron sealed sources (greater than 100 mci) in active use will be tested for leakage at intervals not to exceed six months. All sealed sources in use (greater that 10 mci) designed for the purpose of emitting alpha particles will be tested at intervals not to exceed 3 months. Ni 63 foil sources in use (greater than 100 mci) will be tested at intervals not to exceed 6 months. Test for leakage for sealed sources shall be capable of detecting the presence of uci of radioactive material on a test sample. 23 April 2018 EHS-MAN

23 III.E.7. Monitoring Radiation Surveys and monitoring shall be conducted to determine radiation levels, concentrations or quantities of radioactive contamination and the potential for radiological hazards that could be present. Instruments and equipment used for quantitative radiation measurements are to be calibrated at least every 12 months. III.E.8. Dosimetry Requirements The Licensee is required to supply personal monitoring devices to individuals working with radioactive material if: An adult is likely to receive in 1 year from an external source a dose in excess of 10% the limits. A minor or declared pregnant employee who is likely to receive in 1 year from an external source a dose in excess of 10% the limits. An individual entering a high or very high radiation area. All dosimetry issued by the Environmental Health and Safety Office must be provided by a company certified by the National Voluntary Laboratory Accreditation Program (NVLAP) of the National Institute of Standards and Technology. The dosimeters used at Einstein use optically stimulated luminescence technology to detect radiation exposure. A personal dosimeter (OSD) is worn for a three-month period (1 quarter). The OSD is returned to Radiation Safety at the end of the quarter after the department administrator distributes new badges. The dosimeters are forwarded to a vendor who processes them to determine the exposures. All exposure documentation is held in the Environmental Health and Safety Office. Individual reports will be provided to the wearer upon written request. Figure 14: Dosimetry used to monitor Radiation Exposure III.E.9. Engineering Controls The Licensee must use process or engineering controls, such as containment or ventilation to control the concentration of radioactive material in the air. For a research laboratory this may involve the use of a fume hood or glove box for work with I 125 or tritiated water. 23 April 2018 EHS-MAN

24 Figure 15: Fume hood used as for work with volatile radioactive material III.E.10. Posting Requirements All doors entering rooms where radioactive materials of quantities exceeding those specified in the Rules of the City of New York must be identified with Caution Radioactive Materials labels. In addition, required information supplied by the City of New York must be posted in the laboratory. The Notice to Employees presents information on employer and worker responsibilities and standards for radiation protection. The in-house Licensee (authorized Principal Investigator) is required to label containers storing radioactive material. The label must contain information regarding the isotope and an estimate of the amount of material in the container and the date the material was placed in the container. Figure 16: Labeled Radioactive Material Containers Other potential sources of radiation or contamination that should be labeled include: Laboratory benches on which radioactive material is used. Plexiglass shields. Refrigerators/freezers used to store radioactive material. Sinks used for disposal of radioactive material 23 April 2018 EHS-MAN

25 Potentially contaminated equipment (pipettes, centrifuges, water bath, etc.). Waste storage cabinets and containers. Fume hoods in which radioactive material is used or stored. III.F. Monitoring for Radiation and Contamination There are three primary methods used to monitor for radiation and contamination in a medical research laboratory; with a survey meter, by wearing a dosimeter or by employing the wipe test technique. III.F.1. Survey Meters The survey meter may utilize a Geiger detector or a sodium iodide detector. A Geiger detector is typically used to monitor for beta radiation from beta emitting radioisotopes such as P 32, S 35 and C 14 and gamma or x-rays from Cr 51 or I 125. It cannot be used for tritium as the energy of the beta particle from tritium is so weak it will not penetrate the detector. The basic principle behind the Geiger counter is that the radiation enters a chamber containing a gas that is ionized by the radiation. There is a coil inside the chamber that has a difference in electrical potential between the wall of the chamber. This difference in electrical potential causes the ionized gas molecules generated by the radiation to move towards the coil and the electrons stripped from the gas molecules to move toward the chamber wall. When they strike the coil and wall it generates an electrical discharge which registers as a count on the detector. The rapid clicking you hear is the generation of ions inside the detector from the interaction with radiation. Figure 17: Geiger Counter fitted with a Pancake Probe Figure 18: A Mini-monitor is another form of Geiger Counter found in Labs 23 April 2018 EHS-MAN

26 The sodium iodide probe is another type of detector used in medical research laboratories. It is of particular importance for researchers using I 125 and other gamma or x-ray emitters as it is more sensitive to these types of radiation than a Geiger counter. Figure 19: Sodium Iodide detector used for monitoring I-125 Even if the detector is not near a source or radiation, you may still hear infrequent clicks. This results from natural background radiation. Prior to using a survey meter to monitor radiation levels, it is important that you check the operability of the meter. This consists of checking that: The meter has been calibrated in the last year, The batteries are fully charged, and The meter is capable of detecting radiation. You can tell if the meter has been calibrated within the last year by checking the due date on the calibration sticker on the survey meter. If the Geiger counter was calibrated within the last year you may use the Geiger counter. Otherwise, you should bring it to the Radiation Safety Office for calibration. The charge on the batteries can be checked by switching the meter to the battery test function and observing the deflection of the armature on the meter. If it swings into the battery good region then the batteries are sufficiently charged. Otherwise, the batteries are weak and need to be replaced prior to using the meter. Normally the batteries are regular batteries that can be purchased through a hardware or convenience store. If you want to save some money you should replace them yourself rather than bringing the meter to the Radiation Safety Office for replacement. The meter will be sent out to a vendor who will charge not only for the batteries, but also for their installation. Finally, you should check that the meter is responding to radiation. This can be done by holding the probe up to a known source of radiation and observing that the armature deflects on the meter. If it does, you are ready to use the meter. If not, the meter could be damaged and should not be used. Meters are used for checking radiation levels in the work area to ensure that dose rates are adequately controlled and to check for surface contamination. When monitoring for radiation levels you should ensure that the dose rates in the area do not exceed 0.1 mrem/hr. If the levels are greater than that 23 April 2018 EHS-MAN

27 amount, steps should be taken to reduce them with shielding or by moving the source to another shielded location. If you are using a meter to check for contamination, you should hold the meter approximately one centimeter over the surface being checked. Move the meter slowly (about one detector width per second) over the surfacing you are monitoring for contamination. If you find contamination you should immediately take steps to clean it up. Resurvey to confirm that the contamination level is below applicable limits. III.F.2. Dosimetry As mentioned in section 5.8, a dosimeter is a devise that is used to monitor the total dose an individual receives while working with radioactive material. The Safety Department issues dosimetry to individuals upon request on ilab by the PI. They may call to have the badge mailed to them or may pick the badge up at the Safety Department. Optically Stimulated dosimeters (OSD) are worn for 3 months and should be located on the body between the neck and the chest. At the end of the 3-month period, the OLD should be returned to the Safety Office upon receipt of a new dosimeter. The badge shall always be worn while the researcher is working with radioactive material. Individuals issued a dosimeter are required to complete and sign a letter to their previous employer requesting their past exposure records. A ring or finger dosimeter should be worn on the hand when working with P 32, gamma emitting isotopes or x-ray equipment. If a researcher is working with larger amounts of activity, greater than 500 uci, they should wear a ring badge. It should be worn on the hand that is potentially receiving the greatest exposure. The PI should contact the Safety Office to request a ring badge for any laboratory employees. Pregnant employees who declare their pregnancy to the RSO will be issued a separate badge to monitor fetal exposure. Therefore, it is important that you contact the RSO, meet and receive information concerning fetal risks to obtain the monthly badge if you know or suspect you are pregnant. The badge should be worn for one month and returned to the Department of Environmental Health and Safety upon receiving a new one. III.F.3. Wipe Test Procedures A wipe test is performed to locate contamination in a laboratory or determine if a specific item is contaminated. It is more sensitive than a survey meter for small quantities of contamination and the only method on campus to check for tritium contamination. Wipe tests are conducted routinely to monitor for contamination in an authorized laboratory, to release equipment for repair, or in the event of cleaning a spill. Routine wipe tests of authorized laboratories are required to be performed. However, if a laboratory is using large quantities of radioactive material or radioisotopes not normally used in medical research, the laboratory may need to conduct wipe tests more frequently. The following are areas and items that should be checked for contamination: Laboratory benches or fume hoods used for work with radioactive material The floor in front of a laboratory bench 23 April 2018 EHS-MAN

28 Equipment used with radioactive material such as pipettes, centrifuges and Freezers Refrigerator or freezer door handles in which radioactive material is stored Desks and laboratory door handles Sinks used for disposal of radioactive liquid Floor where radioactive waste is stored. A wipe test map of the laboratory indicating areas and equipment to be wiped must be submitted to the Radiation Safety Officer when applying for a license to use radioactive material in the lab. Typically, a minimum of 10 wipes should be taken per radioisotope laboratory. If the laboratory has one centralized location for using radioactive material, it requires fewer wipes than if material is used throughout the laboratory. Each area where radioactive material used requires wipe tests. The floor adjacent to the radiation use area should be monitored as well. Use a piece of filter paper or Q-tip to perform wipe tests. Wipe an area of approximately 100 cm 2. Place the wipe in a scintillation vial and add liquid scintillation fluid. Run the scintillation vials in a liquid scintillation counter. Use a counting protocol that detects the radioisotopes used in the laboratory. If you find contamination, promptly decontaminate the areas or equipment down to acceptable levels. The acceptable level for contamination in a laboratory is less than 1000 dpm/100 cm 2. After decontamination, perform a second wipe of the area or equipment to confirm it is below 1000 dpm/100 cm 2. Continue decontamination efforts as required. Figure 20: Conducting a wipe test The results of wipe tests must be kept on file for review by Radiation Safety during inspections. This includes wipe tests conducted following decontamination efforts. The records should consist of a wipe test map showing the locations monitored for contamination and printouts from the liquid scintillation counter showing the results of the analysis. All wipe test results should be recorded in disintegrations per minute (dpm). It is requested that you file the results in the Radiation Safety Manual notebook. III.G. ALARA Exposure and Contamination Control When working with radioactive material it is prudent to keep your exposure to a minimum. The acronym for this common approach to radiation control is ALARA (As Low as is Reasonably Achievable). The policy requires that exposure be monitored with radiation dosimetry and records be reviewed to ensure 23 April 2018 EHS-MAN

29 that individuals are keeping their dose to a minimum. There are various methods for controlling exposure to radiation and contamination when working with radioactive material. III.G.1. Time One method of reducing exposure is to minimize the time you spend near a radiation source. This can be accomplished by having thorough knowledge of the experimental protocol you are performing so that you can complete the procedure in a minimum amount of time. If you are new and have not used radioactive material or the particular experimental protocol, you may want to conduct a dry run. With this approach, you perform the procedure without the radioactive material. You can improve your confidence with the procedure and may come up with ideas for minimizing your exposure in the process. III.G.2. Distance Distance can be used to significantly reduce your exposure to radiation from a radioactive source. The amount of radiation at a specific distance from a source is inversely proportional to the square of the distance from the source to the target. DR B = DR A x [R A] 2 /[R B] 2 Where; DR B = the dose rate at point B DR A = the dose rate at point A R A - the distance from the source to point A R B = the distance from the source to point B As an example, consider Cr 51 that gives off gamma radiation in the amount of 100 mr/hour at 1 meter from the source (Point A). If you are standing at the point and move back 1 meter, you are now 2 meters from the source (Point B). The dose rate at that point may be calculated from the equation above and found to be: (100 mr/hour) x (1 meter) 2 /(2 meters) 2 = (100 mr/hour) x (1/4) = 25 mr/hour Figure 21: In the top image the Geiger counter is 15 inches from a source of radiation. It is reading 40 mrem/hour at that distance. In the bottom image the Geiger counter is moved back to 30 inches from the source. It now reads about 10 mrem/hour or one quarter of the initial exposure for twice the distance from the source. 23 April 2018 EHS-MAN

30 If you are working with radioactive material, you should keep as much distance from you and the source. You should also store sources of radiation in remote areas of the laboratory away from desks and work areas as much as practicable. III.G.3. Shielding Finally, you should use shielding to minimize your exposure to radiation from radioactive sources. Typically, the more shielding you use to protect yourself from a source of radiation, the less exposure you will receive from the source. The type and amount of shielding depends on the type and amount of radioactive material you are using. If you are using gamma or x-ray emitters, then shielding with lead is the best choice. For high energy beta emitters, plexiglass or Lucite shielding should be used. As an example, consider shielding for microcurie sources of I 125 which emits x-ray and gamma radiation. The energy for these radiations is extremely small, on the order of kiloelectron-volts (Kev). Therefore, only a few millimeters of lead sheet are needed to significantly reduce the radiation from I 125. Figure 22: Lead foil for shielding radiation from I-125 P 32 is a high energy beta emitter with a maximum energy of 1700 Kev. To shield yourself from microcurie sources of P 32 you will need about 1-centimeter thick Lucite shielding. This will effectively stop the majority of the beta particles emitted by P 32. Figure 23: Plexiglas Shield for working with P April 2018 EHS-MAN

31 III.H. III.H.1. Working Safely with Radioactive Material General Requirements Use the following general precautions for working with all radioactive material. III.H.1(a) Preparation Designate and label areas for working with radioactive material. Label all containers with radioactive material labels. Specify the isotope, activity and date. Label all equipment or apparatus used with radioactive material. Include centrifuges, hybridization ovens, water baths, etc. No eating, drinking, applying cosmetics or smoking in the laboratory. No mouth pipetting of radioactive material. Designate and post work areas Label containers for storing radioactive material Label equipment such as centrifuges No eating or drinking in the laboratory III.H.1(b) Conducting Research Use spill trays and absorbent pads when working with radioactive material to absorb accidental spills. Use a fume hood for handling potentially volatile material such as I125. Use a glove box for handling large quantities of volatile material such as 10's of mci of I125. Wear a laboratory coat, disposable gloves, and laboratory safety glasses. Ensure that the gloves are appropriate for the chemicals being handled. 23 April 2018 EHS-MAN

32 Use a tray with absorbent for work with all radioactive material Use a fume hood for work with volatile radioactive material Use a glove box for work with large quantities of volatile radioactive material Wear a lab coat, gloves, dosimeter and safety glasses III.H.1(c) Post Research Monitor and, if necessary, decontaminate surfaces. Use the wipe test method to detect low energy beta emitters. A survey meter is suitable for detecting high energy beta, gamma and x-ray emitters. Dispose of radioactive waste in appropriate waste containers. Assume that an item is contaminated if you have used it with radioactive material. Dispose of liquid radioactive waste down the sink in accordance with limits specified on the sink disposal chart. Store radioactive material in the refrigerator/freezer. Conduct routine wipe tests surveys. Monitor work area for contamination Dispose of radioactive waste Store radioactive material in refrigerator/freezer 23 April 2018 EHS-MAN

33 III.H.2. Low Energy Beta Emitters Use the following requirements for working with low energy beta emitters such as H 3, C 14 or S 35. Follow general requirements for working with radioactive material in section 8.1. Dosimetry is not required when handling Tritium. Most research involving low energy beta emitters may be performed on a laboratory bench. Shielding is not required for low energy beta emitters. Use the wipe test method and a liquid scintillation counter to monitor for contamination. Urinalysis is required with 24 hours after working with large quantities of material (100's of millicuries). Dispose of radioactive waste in an appropriate radioactive waste container. Assume an item used with radioactive materials is contaminated unless you can demonstrate with wipe test results that it is not. Work on open bench, no shielding required Use wipe test method and analyze with Liquid Scintillation Counter Dispose of dry solid waste in a radioactive waste container Dispose of Scintillation vials in separate waste container III.H.3. High-Energy Beta Emitters Use the following requirements when working with high energy beta emitters such as P 32. Follow general precautions for working with radioactive material listed in section 8.1. Always wear a body dosimeter when working with P 32. Wear a ring dosimeter when using <500 uci of P 32. Use 1 cm thick Lucite or plexiglass shielding when handling mci quantities of material. For larger quantities of material add 3 to 6 mm of lead to the outside surface of the Lucite shield. Conduct dry-run experiments to ensure dexterity and speed of handling P 32. Routinely monitor gloves for contamination and replace if highly contaminated. Routinely monitor work area for contamination and decontaminate to minimize exposure. Urinalysis is required within 24 hours after working with 100 mci or greater of P 32. Dispose of radioactive waste in a labeled, shielded waste container. 23 April 2018 EHS-MAN

34 Dosimetry is required for work with P-32 Use a plexiglass shield Use a Geiger counter to routinely monitor area Dispose of waste in a plexiglass container III.H.4. X-Ray and Gamma Emitters Use the following requirements when working with x-ray or gamma emitters such as I 125 or Cr 51. Follow general precautions for working with radioactive material specified in section 8.1. Store stock material in a shielded container. Whole body dosimetry is required for work with large quantities (mci). Minimize exposure with lead shielding. Use GM or NaI detector to monitor for gross contamination and a liquid scintillation counter for monthly wipe tests. Urinalysis is required within 24 hours after working with 100 mci or greater. Dispose of radioactive waste in a radioactive waste container. Wear dosimeter when working with x-ray or gamma emitters Use lead shielding when storing or handling large quantities of x-ray or gamma emitters Use a sodium iodide detector for x-ray or gamma emitters Store low energy gamma emitters in a metal waste container 23 April 2018 EHS-MAN

35 III.I. Radioactive Waste Disposal It is important that radioactive waste is properly disposed in an appropriate waste container. If radioactive waste is placed in a medical waste container or into the regular waste, it could have serious consequences for Einstein if discovered by the Colleges waste vendors. The College could lose access to waste disposal facilities and/or access to the incinerator for the destruction of the medical waste. In addition, if reported to the City Bureau of Radiological Health, the College could be fined for the violation of city regulations or lose its radioactive materials license. There are a variety of types and classifications for radioactive waste. The types of radioactive waste generated at Einstein are dry solid waste, liquid waste, liquid scintillation vials, mixed waste, biological and animal carcasses. In addition, radioactive waste is classified according to its half-life; long half-life material or short half-life material. Long half-life material includes H 3 and C 14, while short half-life material includes P 32, P 33, I 125, S 35 and Cr 51. Long lived radioactive waste must be considered permanently radioactive and disposed through a waste broker as radioactive waste. Short lived radioactive waste may be held for decay for 10 half-lives and disposed as non-radioactive medical waste. Table 9: Ten Half-Lives for Common Radioisotopes Isotope Half-Life Minimum Storage Time (10 half-lives) P days 6 months S days 3 years I days 2 years Cr days 1 year H years N/A* C 14 5,730 years N/A* *Only radioisotopes with half-lives less than 90 days are considered short lived radioisotopes and may be decayed prior to disposal as medical waste. III.I.1. Dry Solid Waste Dry, solid waste consists of paper plastic, glass and rubber gloves. It can include small amounts of liquid absorbed onto paper towels or absorbent pads and empty stock containers of radioactive material. Dry Solid waste may be either long lived or short-lived material. Long lived dry solid waste including H 3 and C 14 should be placed in a radioactive waste container separate from short lived material. The short-lived material should be segregated by isotope and placed in separate containers. That is, one waste container for P 32 ; one for S 35 ; and one for I 125, etc. The reason for separating the short-lived radioisotopes from one another is because of the differences in each of their half-lives. The half-life of P 32 is 14.3 days, while the half-life of S 35 is 87.4 days. Therefore, P 32 may be held for decay for only 6 months prior to disposal whereas S 35 must be held for 3 years prior to disposal (see Table 9 above). The Department of Environmental Health and Safety (EH&S) provides radioactive waste containers to laboratories. However, the department does not provide plexiglass waste containers for P 32. The PI must 23 April 2018 EHS-MAN

36 purchase this for their laboratory. EH&S provides the laboratories with 5, 10, 30 and 55-gallon containers for the collection of radioactive waste. Sharps such as syringes, needles, razors, etc. should not be placed directly into a radioactive waste container. This waste type should be placed in a sharps container labeled with a Caution Radioactive Material sticker. If the sharps container contains long lived radioactive material such as H 3 and C 14, complete a radioactive waste ticket and forward it to EH&S for pickup. If the sharps container contains short lived radioactive waste, once it is full it can be held for decay or given over to Radiation Safety for decay. Once decayed, it must be surveyed by Radiation Safety and disposed as medical waste. Long lived dry solid waste containers must be picked up by EH&S for proper disposal. The PI should submit an ilab form to EH&S requesting the pickup. Containers with short lived radioisotopes must be picked up by EH&S for decay or stored in a secure area of the laboratory and decayed. If the PI decides to store the material in the laboratory for decay, they must place it in a labeled durable container, ensure that custodians do not accidently remove it from the laboratory, ensure that the radiation levels from the material is less than 0.1 mr/hour, and hold it for 10 half-lives. Once the material has been decayed for 10 half-lives the decayed waste must be picked up by EH&S for survey and disposal as medical waste. The PI should submit a form on ilab requesting a pickup of waste for decay or decayed waste. The disposal of decayed radioactive waste must be done in a manner that is compliant with City, State, and Federal regulations. It has been our experience that many investigators do not give enough care to properly managing their radioactive waste and do not maintain the required records, therefore, we strongly suggest that you call EH&S for the disposal your radioactive waste. III.I.2. Liquid Waste Liquid waste may be disposed in three different manners; it may be poured down the drain, held for decay and then poured down the drain, or placed in a durable plastic container for removal by Radiation Safety. Liquid waste poured down the drain must be done so in accordance with sink disposal limits (see Table 10 below). All sink disposals must be documented as to the radioisotope, the amount of material and the date of disposal. This must be documented on the sink disposal log. Liquid waste held for decay should also be placed in a durable container that will not readily break if dropped and sealed with a cover. Liquid containers should also be placed in a secondary container to prevent spills. An ilab form is required to be completed and submitted for the disposal of liquid waste through EH&S. Table 10: Limits for Sink Disposal Radioisotope Limit/Month/Lab (uci) Average/Day/Lab (uci) P S I Cr H C April 2018 EHS-MAN

37 III.I.3. Liquid Scintillation Vials Scintillation vials are typically collected in 5- or 10-gallon drums. Scintillation vials should be separated according to whether it is a long-lived radioisotope or short-lived radioisotope and whether or not biodegradable scintillation fluid is used. Lower activities of H 3 and C 14 scintillation waste (< 0.05 uci/ml of liquid) are Deregulated and therefore least expensive to dispose. Liquid scintillation vials containing larger amounts of H 3 and C 14 are classified as Non-Exempt and are significantly more expensive to dispose. Isotopes such as P 32, S 35, I 125 and Cr 51 are Regulated isotopes and should be separated from H 3 and C 14. While it is not absolutely necessary that you separate these waste types it does save money for the PI. All scintillation analysis should be performed with biodegradable fluids. If non-biodegradable fluids are required for analysis the vials must be separated from biodegradable scintillation vials. The PI should complete a form on ilab requesting a pickup of waste. There is an alternative to disposing smaller amounts of scintillation vials through EH&S. Biodegradable scintillation fluids may be poured down the sink, saving the PI the cost of drum disposal through a waste broker. However, when considering the cost, the PI should also consider the cost of having a staff member pour the liquid from each scintillation vial down the sink and rinsing out each vial. Also, the sink disposal limits apply for the disposal of radioactive material in scintillation vials down the drain as it does with liquid waste. III.I.4. Mixed Waste Mixed hazardous waste is any combination of radioactive, chemical or medical waste: for example, H 3 mixed with carbon tetrachloride or phenol. It is strongly recommended that you avoid generating such waste as it can be difficult to dispose and extremely expensive. Please contact the RSO or EH&S if you expect to generate this type of waste in your research. Your laboratory will be responsible for the costs associated with the generation of mixed hazardous waste. III.I.5. Animal Carcasses The disposal of animal carcasses is a little more complicated than the disposal of dry, liquid, and scintillation waste. First, you need to consider whether it is long lived or short-lived waste. If the animal carcasses contain short-lived radioisotopes such as P 32, S 35 or I 125, they can be stored for decay in a freezer for 10 half-lives and discarded as medical waste. Request a final survey by EH&S on ilab. If an animal carcass contains H 3 or C 14, the concentration of the radioisotope in the carcass must be considered. If the concentration is equal to or less than 0.05 uci/gram of animal, the animal carcass is considered nonradioactive and can be disposed as medical waste. If the activity of the H 3 and C 14 is greater than 0.05 uci/gram, the carcass must be considered radioactive and frozen until you request pick-up on ilab by EH&S. Stored animal carcasses must have the P.I. name, the isotope and activity and date. III.I.6. Biological Waste Radioactive wastes that contain biological materials are treated in the same manner as animal carcasses. Some common biological wastes include animal bedding from animals involved in studies using radioactive materials, tissue samples containing radioisotopes, and waste items that have been exposed to blood or bodily fluids. All of the biological waste should be preserved by freezing to minimize decay. If the waste contains short lived isotopes it can be disposed as medical waste after 10 half-lives. If it 23 April 2018 EHS-MAN

38 contains long lived isotopes, such as H 3 or C 14, it must remain frozen until you request pick-up on ilab by EH&S. For more details about waste disposal, please see a copy of Einstein s Waste Disposal Policies and Procedures. III.J. Emergency Procedures Emergency procedures must be posted in each laboratory in which radioactive material is used. What follows provides additional information for responding to an emergency situation. III.J.1. Minor Spills Spills that involve no radiation hazard to personnel involving weak beta emitters such as H 3 or C 14 for a spill of up to 100 uci, or when survey meter readings are less than or equal to 2.5 mr/hour. 1. Contain the spill using paper towels or absorbent pads to minimize spread of the liquid. 2. Immediately notify all persons in the room. 3. Minimize the number of individuals in the area. Estimate the activity spilled. 4. Wear gloves, lab coat, and safety glasses for cleaning up the spill. 5. Using paper towels, remove the contaminated material from the outer perimeter of the spill inward. 6. Avoid spreading the contamination beyond its original area. 7. Use a soap solution or professional decon solution spray and paper towels to decontaminate the affected area. 8. Dispose of all paper towels in a radioactive waste container. 9. Check the area for contamination using the wipe test method. 10. Repeat decontamination efforts until the contamination levels are below acceptable limits.* 11. Dispose of gloves and other potentially contaminated items as radioactive waste. * If contamination remains after 4 or 5 attempts, contact the Radiation Safety Office. III.J.2. Major Spills This spill involves a potential radiation hazard to personnel. 1. Attempt to contain the spill. 2. Notify all persons not involved in the spill to vacate the room at once. 23 April 2018 EHS-MAN