Radiation Protection Training Manual (cont2)

Chapter 10: RADIATION SAFETY FOR X-RAY UNITS

10.1 Nature of analytical X-rays

Analytical X-ray instruments produce intense beams of ionizing radiation that are used for diffraction and fluorescence studies. At U of T, there are also numerous X-ray producing machines for medical and/or dental applications.

The part of the beam that corresponds to the shell (K, L, M, etc.) emission of the target material is called characteristic x-ray radiation. In addition to the characteristic radiation, a continuous radiation spectrum is produced, ranging from very low energy to the maximum setting. Undesirable parts of the x-ray may be filtered out using cones, diaphragms and collimators.

Fig. 10-1: Typical X-ray spectrum

The primary beam of the x-ray machine is not the only source of ionizing radiation. Any high voltage discharge is a potential source of X-rays. Faulty high-voltage vacuum-tube rectifiers may emit X-rays of twice the voltage applied to the X-ray tube. Other sources of ionizing radiation are:

  1. Secondary emissions and scattering from the sample, shielding material, and fluorescent screens
  2. Leakage of primary or scattered X-rays through gaps and cracks in shielding
  3. Penetration of the primary beam through or scattering from faulty shutters, beam traps, or collimator couplings

X-rays emitted from an open, un-collimated port form a cone of about 30 degrees. A collimator can reduce the beam size to about a 1-millimetre diameter.

Fig. 10-2: Collimator

10.2 X-ray hazards and biological effects

X-rays produced by diffraction machines are readily absorbed in the first millimetres of tissue, and therefore do not contribute any dose to the internal organs of the body. However, the lens of the eye can receive a significant dose from X-rays of this energy. Overexposure of lens tissue can lead to the development of lens opacities and cataracts.

An absorbed dose of a few grays may produce a reddening of the skin (erythema) which is transitory. Higher doses to the skin – 100 Gy and greater – may produce significant cellular damage resulting in pigment changes and chronic radiation dermatitis. Exposure to erythema doses may not result in immediate skin reddening. The latent period may be from several hours to several days.

X-rays used for medical purposes are about one order of magnitude shorter in wavelength. Diagnostic rays are designated for tissue penetration and are carefully filtered to avoid X-ray damage to the skin caused by the longer, more readily absorbed wavelengths.

10.3 Safety precautions, shielding

A calculation code for the shielding of X-ray beams (primary and secondary barriers) for controlled and non-controlled areas for open-beams equipment can be found at

https://ehs.utoronto.ca/our-services/x-ray-safety/x-ray-barriers/

Precautions are necessary when working with X-ray machines.

Before the removal of shielding or before beginning work in the sample area, the operator must check both the warning lights and current meter on the console or computer. The best way to avoid accidental exposure is to turn the machine off before working in the sample area.

Normally, the new cabinet enclosed equipment has interlocks installed so, when the door is opened, the X-ray production is immediately turn off.

Never put any part of the body in the primary beam. Exposure of any part of the body to the collimated beam for even a fraction of a second may result in damage to the exposed tissue.

If an instrument malfunction is suspected, the machine should be turned off and unplugged. A notice should be placed on the control panel until the instrument is repaired. A qualified person must perform all repairs. Alignment procedures also require special training and knowledge. Such service to X-ray emitting devices must be reported to the Radiation Protection Service.

10.4 Eye protection

The use of safety glasses is encouraged when working with analytical X-rays. While glasses cannot provide complete protection to the eyes, they can reduce X-ray exposure. Glass provides about 10 times the protection of plastic but neither one will adequately protect the eye from direct exposure to the primary beam.

10.5 Tube status indicators

There must be a visual indication located on or near the tube head to indicate when X-rays are being produced. This is usually an assembly consisting of two red bulbs, wired in parallel and labelled X-RAYS ON. If one of the bulbs is burned out, the operator should either replace it before leaving the room or leave a note on the light assembly indicating that the bulb is burned out. An unlit warning bulb does not necessarily mean that X-rays are not produced. Never trust a bulb, unless it is illuminated ON! Always check the control panel or the computer when the bulb is off.

Fig. 10-3: A warning light

10.6 Safety devices – interlocks

Interlock switches are used to prevent inadvertent access to the beam. They should not be bypassed. Interlocks should be checked periodically to ensure that they are functioning properly.

Interlocks and other safety devices, including warning systems, are not foolproof or fail-safe. A safety device should be used as a backup to minimize the risk of radiation exposure, never as a substitute for proper procedures and good judgement.

10.7 Registration of X-ray instruments

Users of X-ray-producing devices on U of T campuses (or in areas that are controlled by the U of T) must register their instrument with the University RPS. Registration is necessary for the reporting requirements of the Ontario Ministry of Labour (MOL) and the Ministry of Health.

The following information is required for registration:

  1. Type of device (dental, crystallography, fluorescent, medical, etc.)
    • Name of Manufacturer
    • Model of the device
    • Serial number
    • Maximum voltage
    • Maximum current
    • Building and room number where the instrument is located
    • Department to which the instrument belongs
    • Name and telephone number of the person in charge of the instrument

More information about the U of T X-ray safety program can be found at https://ehs.utoronto.ca/x-ray-safety-program

Chapter 11: U of T EMERGENCY PROCEDURES

11.1 Emergency response procedure for radioactive material spill

The most common radiation emergency when working with open sources is a spill. When a spill of radioactive material occurs, an important consideration must be given to the prevention of the spread of the material.  All spills of radioactive material must be cleaned up immediately.

11.1.1 Spill on objects

When a spill of radioactive material on objects occurs, the following steps must be taken:

  • Injuries first: First aid to the injured persons takes precedence over the spill cleaning. When emergency personnel arrives, advise them about the radioactive materials involved. 
  • Alert everyone in the area: Ensure that everyone near the accident has been alerted. Mark the area and post a sign if necessary, to prevent anyone from walking on the spilt material.

  • Confine the spill: Take action to prevent the spread of the material.  If the material is dry, lightly dampen it.  If it is wet, cover it with dry absorbent.

  • Clear the area: Remove all persons from the vicinity of the spilt material.  Minimize movement in the area.

  • Decontaminate: Apply decontamination procedures in this order: personnel, laboratory, and equipment.

  • Summon aid: If there is any doubt about cleaning up the spill, the spill involves more than 100 Exemption Quantities (EQ) of radioactive material, contamination of personnel, or release of volatile material, contact the Radiation Protection Service.

During normal working hours 416 978-2028
Nights & weekends  
St. George Campus 416 978-2222
University of Toronto at Mississauga 905 569-4333
University of Toronto at Scarborough 416 078-2222
Aerospace (UTIAS) Campus 416 978-2222

State:

  1. your name, phone number, location (building & room)
  2. that the accident involves radioactive material
  3. if there are any injuries

Wait for assistance to arrive.

11.1.2 Spill on a person

If a person is suspected of being contaminated with radioactive material, complete the following:

  1. immedi­ately assess the location and extent of the contamina­tion
  2. use appropriate monitoring procedure, to locate the material and provide an assessment of the amount
  3. remove any contaminated clothing, place in a plastic bag, labelled as to contents, tape shut
  4. monitor to determine if any skin contamination has occurred, its location and the extent
  5. if contamination involves I-123, I-124, I-125 or I-131 contact RPS for a thyroid screening

If contamination of the skin is identified, notify the permit holder and RPS immediately. If necessary, the SRSO or his/her delegate will inform the CNSC immediately and will prepare and send a report to the CNSC within 21 days.

If the skin is intact proceed as follows:

  1. flush contaminated area with copious amounts of warm water
  2. wet hands and apply mild soap or detergent, lather well with plenty of water
  3. wash for 2 to 3 minutes and rinse thoroughly, keeping rinse water confined to the contaminated area as much as possible
  4. monitor the effectiveness of removal by use of appropriate survey techniques
  5. repeat wash/rinse procedure if necessary
  6. if further washing does not remove the contamination, contact the RPS.

11.2 Emergency response in case of an intake of radioactive material

As described in item 4.6 an internal irradiation of a person occurs in case of an intake of radioactive material. There are 3 major principal pathways for radioactive materials to enter the body: ingestion, inhalation and through the skin.

Ingestion can be the result of not following the rules regarding the food and drinks in the radioactive laboratories. In this case, food or drinks may be contaminated with radioactive materials. Ingestion can also result when the gloves are not removed and the hands are not washed when finishing the radioactive work. In this case, contamination of the hands or gloves can be transmitted to the food or drink.

Inhalation can be the result of producing aerosols, vapours or fumes during radioactive work. When this is possible, the work must be performed in a fumehood or glove-box. It is also possible in case of a spill of a material with high volatility.

Penetration through the skin can happen as a result of a spill on a person or a cut.   

If the radioactive material involved in the intake is chemically toxic as well as radioactive, treat for chemical toxicity first. Prompt medical attention is the best procedure. Personnel working with radioactive material should understand its chemical and radioactive properties to ensure that a prompt response to a suspected intake of material can be carried out.

If an intake of radioactive material is suspected contact RPS immediately and follow the instructions given by the Health and Safety Officer.

11.3 Emergency response in case of external exposure to radiation

External exposure to radiation may occur when working with high activity radiation sources or with open beam X-ray machines. The open sources used in the U of T laboratories are not high enough to cause significant external exposure. However, high activity sealed sources are present in some laboratories and especially in the irradiators. These sources are surrounded by large amounts of lead, iron and other high Z materials, diminishing the risk of radiation exposures.

In case of known exposure to external radiation coming from a radioactive source or an X-ray machine, the person must leave the area without crossing the radiation field, and contact the RPS immediately.

Chapter 12: Glossary

A B C D E F G H I J L
                     
M N O P Q R S T U W X

A

Absorption

The process by which radiation transfers some, or all, of its energy to the medium through which it is passing.

Absorbed Dose

Absorbed dose is a measure of the energy deposited by radiation in a certain material. The SI unit for absorbed dose is the gray (Gy). One gray is an absorbed radiation dose of 1 joule per kilogram. 1 Gy = 1 J/kg.

Absorption Coefficient, Linear (m)

The fractional decrease in the intensity of a beam of gamma or X-radiation as it passes through an absorbing medium. It is expressed per unit thickness of medium (usually cm-1). The specific value of the linear absorption coefficient depends on the type of absorbing material, the energy of the gamma or X-ray, and the density of the absorbing medium. The value of m is used in the equation I = Io*emx; where I is the intensity of the radiation after passing through the material, I0 is the intensity of incident radiation and x is the thickness of the absorber in the same base units as m (e.g.: when m is measured in cm-1, x is measured in cm).

Absorption Coefficient, Mass (cm2/g)

The mass absorption coefficient is obtained by dividing the linear absorption coefficient of a material by the density of the absorbing material. It is expressed in units of cm2/g. The mass absorption coefficient is independent of the density of the material, while the linear absorption coefficient depends on the density of the material. For example, the mass absorption coefficient of water for 1.0 MeV gamma rays is 0.0707 cm2/g. The linear absorption coefficient of water as liquid (at 20°C) is (0.0707 x 0.998234) = 0.0706 cm-1; and for water as ice (at -20°C) is (0.0707 x 0.99349) = 0.0702 cm-1.

Activation

The process of making a material radioactive by the absorption of neutrons, protons, photons, etc. in a material. Activation is used in a nuclear reactor to allow the analysis of very small amounts of material using the radiation given off during the decay process.

Activity

The rate of nuclear transformations or transitions occurring in a radioactive source. The SI unit of activity is the becquerel (Bq), which equals one disintegration per second.

Acute Effects

These effects usually appear shortly after exposure to high levels of radiation. Among these effects are inflammations of the skin, nausea and vomiting, blood changes, bone marrow damage, etc.

Alpha Particle)

A charged particle consisting of two neutrons and two protons. It is sometimes emitted from the nucleus of high atomic number elements during radioactive decay. The alpha particle is the nucleus of a Helium-4 atom. Due to the +2 charge, it causes ionizations along its path length. An alpha particle will travel a few centimetres in air and is stopped by a sheet of paper or the skin’s layer of dead cells.

Annihilation Radiation

The radiation is emitted as a result of the interaction of a positron (positively charged beta particle) and an electron (negatively charged beta particle). The annihilation of these particles results in the disappearance of the two particles and the formation of two gamma photons each of 0.511 MeV, moving in opposite directions.

Annual Limit on Intake (ALI)

An ALI is the amount of activity of a radioisotope, measured in becquerel (Bq), which if ingested or inhaled, will result in a maximum committed dose of 20 mSv in a “reference person” for the next 50 years.

Anti-neutrino, Electron

Elementary particle without rest mass accompanies beta minus (electron) particles during disintegration. The electron anti-neutrino shares energy with the electron, which is why the beta energy spectrum is continuous.

As Low As Reasonably Achievable (ALARA)

It is the principle of radiation protection demanding that the number of people exposed, and the magnitude of their doses should be kept as low as reasonably achievable (ALARA), taking into account economic and social factors (optimization of protection)

Atom

Greek origin (atomos = indivisible), the atoms are the fundamental building blocks of matter. Contrary to their names, atoms have structure. The heavy nucleus is surrounded by lighter electrons moving around in shells.

Atomic Number (Z)

The number of protons in the nucleus of an atom. The atomic number determines the chemical properties of the element. Atoms with the same atomic number but with different numbers of neutrons are called isotopes.

Atomic Mass Number (A)

The total number of neutrons and protons in the nucleus of an atom.

Attenuation

The reduction in the intensity of radiation when is absorbed in a medium as it passes through it

B

Background Radiation

Radiation arising from natural sources in the environment. The main sources of ionizing radiation in the environment are radon gas in the air, radiation from rocks and soil, radiation from ingestion (food and water) and cosmic radiation. The annual effective dose from all-natural radiation sources in Toronto, Ontario, is approximately 1.59 mSv.

Becquerel (Bq)

The SI unit of radioactivity. 1 Bq is equivalent to 1 disintegration per second.

Beta Particle (b)

A charged particle is emitted during a beta disintegration. It has a mass equal to 1/1837 of the mass of the proton and an electrical charge equal in value. When its electrical charge is negative, it is called an electron. When the electrical charge is positive, it is called a positron.

Bioassay

The assessment of the uptake of radioactive materials into the body. Two methods are available, in vitro and in vivo. The former involves taking a specimen, usually a fluid such as urine, and measuring the radioactivity in it by use of a suitable counter. The material is assessed externally to the body. In vivo techniques involve placing a radiation monitor near the body and measuring the radioactivity being emitted from radioactive material within the body. An example of this is the use of a detector placed near the thyroid to measure uptake of I-125 by counting the gamma radiation emanating directly from the gland.

Bremsstrahlung

A phrase derived from the German language means “braking radiation”. When a charged particle (generally referring to beta particles) passes close to a nucleus, a change in the velocity of the particle will cause a loss of the particle’s energy by electromagnetic radiation. The bremsstrahlung photons have a continuous spectrum of energy distribution below the maximum kinetic energy of the charged particle. The likelihood of bremsstrahlung production increases with the atomic number of the absorbing material. Therefore, it is better to use low Z materials for protection against beta radiation.

C

Calibration

The process of determining the efficiency of equipment used for radiation monitoring. The response of the instrument to a source of known activity is measured. The resulting efficiency is used to determine unknown activities.

Carcinogenic

The ability of a material to cause cancer, whether it is chemical, biological or physical. b-naphthylamine is an example of a carcinogenic chemical and ionizing radiation is an example of a carcinogenic physical agent.

CNSC

Acronym for the Canadian Nuclear Safety Commission, the federal agency regulating the possession and use of radioactive materials in Canada.

Committed Dose

The total equivalent and effective radiation dose received from a radioactive substance in the body during the 50 years following the intake of that substance for adults, or to the age of 70 for children.

Contamination (Radioactive)

Radioactive material is deposited on a surface or in a medium where it is not wanted. Surface contamination is monitored directly with portable instruments or indirectly through the use of the swipe test.

Counter, Scintillation (also Liquid Scintillation Counter or LSC)

An instrument designed to measure very small amounts of radioactivity, generally from negative beta decay. It involves placing the radioactive material in a vial containing a scintillation fluid. As the radiation is given off, it interacts with the fluid and causes excitation of the molecules. Organic compounds in the mixture convert the excitation energy to fluorescence. The light emitted during the fluorescence is detected by photomultiplier tubes positioned outside of the vial. The signal from the photomultiplier tubes is processed and then converted into counts per minute. Because the radioactive material is intimately mixed with the primary detector – the scintillation fluid, detection efficiency for low energy beta emitters is much higher than with other means of detection.

Curie (Ci)

The former unit for expressing activity. The curie was originally based on the decay of 1 gram of radium and is equivalent to 37 billion disintegrations per second. More common units are the millicurie (mCi) and the microcurie (mCi). This unit is being replaced by the SI unit known as the becquerel (Bq). One mCi is equivalent to 37 MBq.

D

Daughter nucleus (Progeny)

The resulting nucleus of the radioactive decay. Sometimes an unstable nucleus, itself a daughter nucleus, can suffer radioactive decay becoming a parent nucleus for this new radioactive process. In these cases, parent and daughter nuclei form a radioactive decay series.

Decay Constant (l)

The fraction of the number of atoms of a radioisotope that decay in a unit of time. It is expressed as the reciprocal of time (e.g. seconds1) and is related to the half-life by the following equation:

                λ = ln(2) / t1/2     or  0.693 / t1/2                  

Decay, Radioactive

The nuclear transformation of a parent nucleus resulting in a progeny nucleus. During this process, the emission of particles and/or electromagnetic energy can occur. This is also called disintegration.

Decision Limit

A statistical tool is applied to identify whether a radiation measurement is within the background or not. It is also used to calculate the minimum detectable activity (MDA) for the method/instrument used to perform the measurement.

Decommissioning

Actions which are taken in the interest of health, safety, security and protection of the environment, to retire a nuclear facility permanently from service. May also be used to refer to the cleaning of a radioisotope laboratory, equipment, furniture, etc., so that it may be removed from a radioisotope permit.

Delay and Decay

The storage of radioactive waste containing radionuclides with short half-lives for a sufficient time to enable their unrestricted discharge to the environment when their final activity level is below regulatory limits.

Delayed Effects

These effects appear much later after exposure. They can arise from repeated exposures to relatively low levels of radiation, or single exposure to higher levels of radiation. For example different forms of cancer, life-shortening, cataracts, genetic effects, etc.

Deterministic Effects

See Non-stochastic Effects.

De-excitation

The process by which an excited system releases energy to achieve a more stable state.

Disintegration

See Decay, Radioactive.

Disposal, Waste

The permanent and secure containment of radioactive wastes, with no intention to retrieve them.

Dose, Absorbed (see Absorbed Dose)

Dose, Artificial

The dose is received by a person from artificial sources. In Canada, the CNSC imposes a limit of 1 mSv/yr for the public from artificial sources other than for medical purposes. The main contributor to artificial dose for the average Canadian is medical exposure.

Dose, Effective

The tissue weighted sum of the equivalent doses in all specified tissues and organs of the body, given by expressions: 

where HT is the equivalent dose in a tissue or organ, and WT is the tissue weighting factor. The unit for the effective dose is the same as for the unit for absorbed dose, J*kg-1, and its special name is the sievert (Sv)

Dose, Equivalent

The dose in a tissue or organ T given by

 where DTR is the mean absorbed dose from radiation type R (alpha, beta, gamma, neutrons, etc.) in a tissue or organ T, and WR is the radiation weighting factor. Since WR is dimensionless, the unit for equivalent dose is the same as the unit for absorbed dose, J*kg-1, and its special name is the sievert (Sv)

Dose, External

The dose received by a person when the radiation source is situated outside his/her body. Radiation badges are used to measure the external dose. Protection against external exposure is achieved by applying the principle of time, distance and shielding.

Dose, Internal

The dose received by a person from a radioactive material that entered the body. Bioassays are used to measure internal exposure. Inhalation and ingestion of radioactive materials can be prevented by following laboratory rules and good work practices.

Dose Limits

It is the principle of radiation protection demanding that the total dose to any individual from regulated sources in planned exposure situations, other than medical exposure of patients, should not exceed the appropriate limits established by the government.

Dose, Natural

The dose received by a person from natural sources. Natural irradiation is both internal and external. The natural dose from background radiation in Canada is around 2 mSv/yr. The natural dose can vary by a factor of more than 10.

Dose Rate

The dose received by an individual per unit of time Jkg-1s-1. When referring to the effective dose, the unit of measure can be Sv/hr, mSv/day, etc.

Dosimeter

A device used to measure and record the dose of radiation to which a person has been exposed. There are whole body, extremity, skin dosimeters, etc.

Dosimetry

The process of finding the radiation dose. Carried out by either practical measurements or theoretical evaluation.

DPM

Acronym for disintegrations per minute.

E

Efficiency (Counter)

The ratio between the number of counts registered by the instrument and the number of disintegrations of the radioactive source. Efficiency is usually expressed as a percentage. It is a function of the geometry and design of the detector, as well as the internal electronics. It also depends on the type and energy of radiation being monitored.

Electron Capture (EC), Orbital

An unstable proton-rich nucleus may capture an orbital electron (as an alternative to beta plus disintegration) to solve the instability. The electron from the inner shell will react with a proton, changing the nucleus into one with a lower Z number (decreased by 1) in an excited state. During the process, a neutrino is also emitted. From the rearrangement of electrons in the new atom, X-rays will be emitted. The excited daughter/progeny nucleus can get rid of the energy by gamma emission or by internal conversion.

Electron Volt (eV)

A unit of energy. It is commonly used for expressing the energy of particles and/or electromagnetic radiation emitted during radioactive decay. It is the amount of energy gained by an electron travelling through a potential difference of one volt. Common multiples include the kilo electron volt (keV) and the Megaelectron volt (MeV).

Element, Chemical

All atoms belonging to a chemical element have the same atomic number Z (the same number of protons) and the same number of electrons. They all have the same chemical properties and occupy the same position in the periodic table of elements. All atoms forming a chemical element are called isotopes of that element. There are more than 105 different chemical elements.

Equivalent Dose

See Dose, Equivalent

Erythema

Reddening of the skin caused by exposure to radiation. The skin erythema dose (SED) was a unit of radiation exposure in the early part of the 1900s. It is due to the dilation of the capillaries in the skin and occurs with exposure to ionizing radiation doses of about 10 Sv to the skin.  

Excitation

The unstable state of an atom or a nucleus caused by external agents or by radioactive decay. When caused by external agents, the system (atom or nucleus) absorbs energy from the surroundings. An excited system, sooner or later, undergoes the process called de-excitation.

Exposure Dose

The measure of ionization produced in air by gamma or X-radiation. Originally measured in röntgens (R), the current SI equivalent is coulomb per kilogram of air. 1C/kg = 3876 R.

Exposure, Acute

Exposure to a high dose during a short time may produce biological effects within a short period after exposure.

Exposure, Chronic

Continuous exposure to radiation for long periods may cause delayed effects.

F

Fission Reaction

The nuclear reaction resulting in the splitting of a heavy nucleus into two or more nuclei. Accompanied by particles (usually 2 or 3 neutrons) and gamma-ray emissions. The resulting nuclei and accompanying radiation carry large amounts of energy (approximately 200 MeV at the fission of a U-235 nucleus). Can be spontaneous or provoked by neutron absorption. Under certain conditions, neutron production and consumption can sustain the reaction (chain fission reaction). It is used in energy production (in nuclear reactors) or for military purposes (atomic bombs).

Fusion Reaction

The nuclear reaction resulting in the unification of two light nuclei to obtain a new nucleus. Accompanied by particles and energy emission. It is the reaction that produces energy in stars. Still, at the experimental stage for energy production, it is used for military applications (so-called “hydrogen bomb”).  

G

Gamma Ray )

An energetic photon emitted from the nucleus during radioactive decay. The energy spectrum of gamma rays is discrete. Protection from gamma radiation requires lead or concrete shielding. Gamma radiation usually accompanies other types of decay.

Geiger Müller Tube (G-M tube)

The main component of most commonly available radiation detection instruments. It consists of a hollow tube filled with a gas and contains a central electrode running parallel to the length of the tube. The shell of the tube forms the other electrode. The tube is held at a high potential voltage, approximately 800-1200 volts and radiation passing through the gas will cause it to become ionized. The ionization is amplified and detected by the supporting circuitry. The G-M tube may also have a small amount of material wrapped around it to improve its response over a wide range of radiation energies and is known as an energy compensated detector. If the end of the tube is made of a thin material such as mylar, it is called a thin end window detector and the G-M tube can be more sensitive to some alpha and beta radiation.

Genetic Damage

Damage caused to genes in cells that are part of the reproductive organs. Genetic damage does not affect the current generation but may be passed on to future generations.

Gray (Gy)

The SI unit of absorbed dose. It is equivalent to one joule per kilogram. Used to measure deterministic (organ or tissue) effects of radiation.

H

Half-life, Physical

The characteristic time taken for the activity of a particular radioactive material to decay to half of its original value; that is, for half the unstable atoms initially present to disintegrate.

Half-life, Biological

The characteristic time required for the amount of a substance to be reduced to one-half of its initial value from metabolism alone. The biological half-life of a radionuclide does not depend on the radioisotope but on the organ or body system in which the material is deposited, as well as the chemical properties of the radioactive material.

Half-life, Effective

The characteristic time required for radioactive material to be eliminated from a biological system through a combination of the physical and biological removal processes. The effective half-life is a mathematical combination of the physical and biological half-lives of the particular radioisotope.

Half-Value Thickness (HVT)

The thickness of shielding material that is required to reduce the intensity of a given type of radiation to one-half of the original amount. Related to the tenth value thickness (TVT).

Health Physics

The branch of science dealing with radiation protection. It arose as a result of the development of the atomic bomb in the Manhattan Project. There is some suggestion that the phrase arose as a result of the need for secrecy surrounding the development of the bomb. Supposedly, words associated with radiation could not be used and so it was decided to call the field health physics. Persons working in the field of radiation protection may also be referred to as health physicists.

I

IAEA

Acronym for the International Atomic Energy Agency. It is an international body within the United Nations that provides advice and assistance to the member nations on the use of radioactive materials.

ICRP

Acronym for the International Commission on Radiological Protection. Originally known as the International X-ray and Radium Protection Committee founded in 1928, it was reorganized in 1950 to become the ICRP. It is composed of a Chair and not more than 12 members chosen based on their expertise in specific areas without regard to nationality. The ICRP publishes recommendations on radiation protection that are usually the basis of legislation for radiation protection.

Inverse Square Law

The relationship between distance and intensity for gamma and X-radiation. The intensity from a point source is inversely proportional to the square of the distance from the source.

Internal Conversion (IC)

An excited nucleus transmits its energy to an electron from an inner electronic shell (usually K or L). The electron is ejected from the atom carrying the de-excitation energy. The IC electrons are mono-energetic, therefore, they differ from beta minus electrons by both origin and energy spectrum. The IC process is always accompanied by X-ray emissions. IC is an alternative mechanism for gamma emission.

Ion

An atomic particle, atom or chemical radical that carries a net electrical charge, either positive or negative.

Ionization

The process by which electrons are removed or added to atoms to create ions. Radiation that possesses enough energy to remove orbital electrons is called ionizing radiation.

Ionization Chamber

A chamber used for the measurement of radiation exposure. Similar to a Geiger Müller tube, it is operated at much lower electrical potentials. The fundamental principle of gas ionization by radiation still applies but since the potential voltage is not as high, the amount of amplification in the tube is small. Generally used for personal dosimeters and standardization instruments.

Irradiation

The exposure of a material to radiation.

Isotopes

Atoms with the same atomic number (number of protons in the nucleus) but having different atomic mass numbers (because of different numbers of neutrons in the nucleus). Chemically, isotopes of a given element all behave the same although some may be radioactive.

J

Justification

It is the principle of radiation protection demanding that any decision that alters the radiation exposure should do more good than harm.

L

Labelled Compound, Radioactive

A molecule that has had one of its atoms replaced by a radioactive isotope. Once labelled, the path of the molecule can be traced through a biological system.

Latent Period

The period between the exposure to radiation and the expression of radiation injury. Generally applied to cancer induction from chronic radiation exposure, the latent period can be anywhere from 5-10 years for leukemia, to 20-30 years for other types of cancers.

Linear Energy Transfer (LET)

A measure of the rate at which an energetic particle transfers energy to the surrounding medium. Alpha particles have a high LET, while beta particles have a lower LET. The unit for LET is J*m-1 or keV*μm-1.

Linear-non-threshold (LNT) model

A dose-response model which is based on the assumption that, in the low dose range, radiation doses greater than zero will increase the risk of excess cancers and/or heritable disease in a simple proportional manner.

M

Minimum Detectable Activity (MDA)

MDA is a characteristic of the instrument or measurement method. It indicates the instrument’s (or method) limitation to detect radioactive material.

N

Neutron

A nuclear particle having a mass similar to a proton but having no electrical charge. During negative beta decay (b), a neutron disintegrates into a proton, an electron and an anti-neutrino which are then ejected from the nucleus. Neutrons can exist outside of the nucleus and have a high potential for radiation damage since they lose energy in biological materials through scattering. Shielding for neutron sources involves using materials containing large amounts of hydrogen.

Neutron Emission

Accompanies a fission reaction or other type of nuclear reaction. Depending on the type of reaction, the energy spectrum can be discrete or continuous.

Neutrino

Elementary particle without rest mass which accompanies beta plus (positron) particles during disintegration. The neutrino shares energy with the positron giving a continuous beta energy spectrum. It is also emitted during electron capture.

Non-Stochastic Effects (Deterministic Effects)

Injury in a population of cells, characterized by a threshold dose and an increase in the severity of the reaction as the dose is increased. Also termed tissue or organ reaction. An example of a non-stochastic effect is cataract formation in the lens of the eye.

Nuclear Energy Worker (NEW)

A person who, during occupational work, is likely to receive a dose of ionizing radiation above the exposure limit allowed for members of the general public.

Nuclear Reaction

A reaction involving one or more nuclei resulting in the creation of one or more new nuclei. Usually accompanied by particles (electrons, protons, neutrons, alpha, etc.) and /or gamma-ray emissions.

Nuclide

A general term referring to all isotopes of an element.

O

Optimization of Protection

It is the principle of radiation protection demanding that the number of people exposed, and the magnitude of their doses should be kept as low as reasonably achievable (ALARA), taking into account economic and social factors.

P

Parent Nucleus

The original nucleus in a radioactive decay.

Permit Holder

A person who is issued a permit under the university’s licence. Must be approved by the UTRPA.  Permit Holders are held responsible at all times for all aspects of radiation safety in areas under their supervision.

Photon

A quantum of energy emitted in the form of electromagnetic radiation. Gamma photons originate in the nucleus and X-ray photons originate in electronic shells and from the bremsstrahlung process.

Point Source

A source of radiation, the physical size of which is small by comparison with the distance at which the radiation is monitored. The radiation can be considered to arise from a single point.

Positron (b+)

A positively charged electron, emitted from the nucleus during some forms of radioactive decay. A positron will combine with an electron (b-) and result in the production of annihilation radiation. See also Beta Particle.

Principles of Radiation Protection

The current philosophy in radiation protection is covered by three principles:  justification, optimization (ALARA) and dose limits.

R

Radiation

The emission and propagation of particles and electromagnetic rays. Generally used to refer to ionizing radiation.

Radiation Badge

A personal dosimeter that uses solid crystals to monitor radiation absorbed dose. Typically, these crystals are composed of lithium fluoride (LiF) and exhibit radiation absorption characteristics similar to that of human tissue. The ionizing radiation produces small local crystal defects which are stable until the crystal is heated. When the crystal is heated to temperatures of approximately 200°C, the defects are removed and the associated energy is released in the form of light. The amount of light produced is proportional to the number of induced crystal defects which in turn is related to the amount of absorbed radiation.

Radiation, Ionizing

Radiation which removes orbital electrons from atoms, or breaking the molecular bonds, thus creating ion pairs. Alpha and beta particles are more densely ionizing than gamma rays or X-rays of equivalent energy. 

Radiation Protection Service (RPS), U of T

It is an administrative service within the U of T Office of Environmental Health and Safety which carries out the daily operation of the radiation safety program, as directed by the UTRPA.

Radiation Weighting Factor, WR  

A dimensionless factor by which the organ or tissue absorbed dose is multiplied to reflect the higher biological effectiveness or high-LET radiation compared with low-LET radiation. It is used to derive the equivalent dose from the absorbed dose averaged over a tissue or organ.

Radioactive Decay Series

Two or more radioactive decay processes in which the daughter nucleus serves as a parent nucleus for the next process. There are four natural radioactive decay series and large numbers of artificial ones.

Radioactive Isotope

An unstable nucleus which undergoes a nuclear transformation.

Radioactive Material

A substance containing unstable nuclei exceeding a certain concentration limit. It is also called a prescribed radioactive substance, radioactive nuclear substance or nuclear substance.

Radioactivity

The property of a certain nuclide to spontaneously emit particles or gamma or X-radiation following a nuclear transformation.

Radioisotope (Radionuclide)

A radioactive isotope.

Radioisotope User

A person using radioactive materials. He/she has specific responsibilities under different acts and regulations to ensure that work with radiation does not create a hazard to themselves, to others and the environment.

Radiosensitive

Sensitive to the effects of irradiation, principally applied to biological systems. Cells of the body which are easily damaged by exposure to ionizing radiation are termed radiosensitive.

Radiotoxicity

The term referring to the potential of a radioisotope to cause damage to living tissue by the absorption of energy from the disintegration of the radioactive material that is within the body.

Reference Man

A standard model of a human being, developed by the ICRP and detailed in ICRP Report #23. The characteristics of standard man are used when specific body information is not available for dosimetry purposes.

Regulatory Dose Limit

A legal limit on radiation dose specified in the Canadian Nuclear Safety Regulations.

Röntgen Equivalent Man (rem)

The older term used to describe equivalent and effective dose. The SI unit is the Sievert (Sv). 1 Sv = 100 rem.

Röntgen, also spelled Rœntgen or Roentgen (R)

Named after Wilhelm Röntgen, it is a unit of radiation exposure. Useful submultiples include the milliröntgen (mR) and the microröntgen (mR). This is gradually being replaced by the SI equivalent which is coulomb per kilogram of air.

S

Sealed Source

A radioactive source sealed in a container or having a bonded cover, the container or cover being strong enough to prevent contact with and dispersion of the radioactive material under the conditions of use and wear for which it is designed.

Shielding

The use of absorbing material between a source of radiation and the detector or recipient. Shielding absorbs radiation and reduces the intensity of the incident radiation. Shielding is chosen based on its effectiveness for a given type of radiation, its cost and other physical attributes.

SI

Acronym for Système International is the international system of units of measurement.

Sievert (Sv)

The SI unit for equivalent and effective dose. It is gradually replacing the rem. 1 rem = 0.01 Sv. Used to measure stochastic effects – radiation-related cancer and heritable effects.

Somatic Injury

Injury to tissues of the body other than the reproductive organs. The somatic injury affects the current generation but is not passed on to future generations.

Specific Activity (Specific Radioactivity)

The activity of a radioactive material divided by its mass, volume, surface, etc.

Spectrometry (Spectroscopy)

The process of identifying an unknown nucleus, atom, or substance by measuring the energy absorbed during excitation or emitted during de-excitation.

Spectrum, Energy

The distribution of the number of particles or electromagnetic rays counted by an instrument over a certain energy range. The spectrum contains the “signature” of the system (nucleus, atom or substance) and is used in spectrometry. For beta disintegration and bremsstrahlung X-rays, the energy spectrum is continuous, whereas for alpha, gamma and characteristic X-rays the spectrum is discrete.

Stochastic Effects

Malignant disease and heritable effects for which the probability of an effect occurring, but not its severity, is regarded as a function of dose without threshold

Survey Meter

An instrument used to measure radiation, typically radiation exposure dose. The instrument usually consists of an energy compensated Geiger Müller tube and associated circuitry which causes a meter’s needle deflection or another readout in the presence of ionizing radiation.

Swipe Test

The process of measuring contamination by wiping a certain area (approx. 100 cm2) of a surface with a filter paper and placing it in a vial with scintillation fluid for counting in a scintillation counter. The efficiency for the removal of non-fixed contamination with the filter paper is considered 10%.

T

Tenth-value Layer

This is the amount of shielding required to reduce the intensity of gamma or X-radiation to one-tenth of its initial value.

Tissue Weighting Factor, WT

The factor by which the equivalent dose in a tissue or organ T is weighted to represent the relative contribution of that tissue or organ to the total health detriment resulting from uniform irradiation of the body. It is weighted such that:

  

U

Uncertainty

The degree of accuracy of the measuring method and/or instrument. For radioactive measurements, the uncertainty is a sum of the uncertainty in the measurement of the sample, measurement of the background, and other possible sources.

University of Toronto Radiation Protection Authority (UTRPA)

A committee composed of academics and administrators appointed by the U of T Governing Council to exercise complete and all-embracing control of the radiation protection program within U of T jurisdiction.

W

Waste, Radioactive

Any material containing or contaminated with radionuclides in concentrations greater a certain value than would be considered acceptable for uncontrolled use or release, and for which there is no foreseen purpose.

X

X-ray

A form of electromagnetic energy that is produced external to the nucleus of an atom. Typically, X-rays may be produced when orbital electrons are rearranged (characteristic X-rays) or when accelerated electrons are slowed in the presence of a nucleus, such as during the production of bremsstrahlung. X-rays are similar to gamma-rays in the manner by which they are absorbed and shielded. However, whereas gamma rays have discrete energies and originate from the nucleus, X-rays can be emitted with both discrete and a broad spectrum of energies and originate outside of the nucleus.

Chapter 13: MOST COMMONS RADIOSISOTPES USED AT U of T

13.1 Carbon-14

C-14  Nuclide C-14 Decay

Radioactive half-life 5730 years
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 156 keV
ALI    
  Ingestion 34 MBq/y
  Inhalation 1000 MBq/y
Maximum beta range in the air 240 mm
Appropriate method for contamination monitoring Liquid scintillation counter
Shielding material Total absorption in 0.2 mm glass or 0.3 mm plastic
Dosimetry Urine analysis for those that use 68 MBq (1.84 mCi) or more volatile liquids or gases at a time, without containment

Special precautions:

  1. Recommended protective clothing:
    1. Disposable lab coat, gloves (select gloves appropriate for chemicals handled) and wrist guards.
    2. Some organic compounds can be absorbed through gloves therefore wear two pairs of gloves and change the outer layer frequently.
  2. Use disposable absorbent liners on trays.
  3. Be careful not to generate carbon dioxide and handle potentially volatile or dusty compounds in a fume hood.

13.2 Calcium-45

Ca-45 Nuclide Ca-45 Decay

Radioactive half-life 162.61 days
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 257 keV
ALI    
  Ingestion 26 MBq/y
  Inhalation 8.7 MBq/y
Maximum beta range in the air 520 mm
Appropriate method for contamination monitoring Geiger-Muller; Liquid scintillation counter
Shielding material Total absorption in 0.3 mm glass or 0.6 mm plastic
Dosimetry Urine analysis for those that use 17.2 MBq (0.46 mCi) or more volatile liquids or gases at a time without containment. Contact the U of T radiation protection Services if you use larger quantities

Special precautions:

  1. Calcium-45 is considered highly radiotoxic because of its affinity for the bone. Radiocalcium has a long biological half-life and can cause damage to the blood-forming organs. Calcium reacts with water, producing hydrogen. If concentrated, the gas becomes a fire and explosion hazard. Calcium also poses a fire and explosion hazard when heated or when in contact with strong oxidizing agents.
  2. Recommended protective clothing:
    1. When working with unsealed sources wear appropriate protective clothing, such as laboratory coats, coveralls, gloves, and safety glasses/goggles.
    2. Laboratory coats must be monitored before leaving the laboratory.
    3. Use a suitable mask if the radioactive material is in the form of dust, powder or if it is volatile.
  3. The metabolism of Calcium is complex. The majority is deposited in the bone and is retained with a long biological half-life (18000 days/50 years). A smaller fraction is eliminated immediately via the urine but eventually, half of the radionuclide is eliminated via the feces.

13.3 Chromium-51

Cr-51 Nuclide Cr-51 Decay

Radioactive half-life 27.70 days
Decay mode e capture
Principal emissions gamma; X-rays
Gamma / X-ray energy 257 keV / 5 keV
ALI    
  Ingestion 530 MBq/y
  Inhalation 560 MBq/y
Appropriate method for contamination monitoring Geiger-Muller; Gamma counter; Solid scintillation detector; Liquid scintillation counter
Shielding material Lead; half-value layer = 0.17 cm
Dosimetry Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Chromium and chromate salts are suspected carcinogens of the lungs, nasal cavity and paranasal sinus, also experimental carcinogen of the stomach and larynx. Skin exposure to chromate salts may result in dermatitis. Sodium chromate (Cr-51) solution may emit radioactive fumes containing Cr-51 when heated to decomposition.
  2. Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  3. Minimize handling time.
  4. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels.
  5. Use disposable absorbent liners on trays.

13.4 Copper-64

Cu-64 Nucide Cu-64 Decay

Radioactive half-life 12.7 hours
Decay mode e capture
Principal emissions gamma; X-rays
Gamma / X-ray energy 511 keV (36%); 1345.8 keV / 8 keV
ALI    
  Ingestion 170 MBq/y
  Inhalation 130 MBq/y
Appropriate method for contamination monitoring Geiger-Muller; Gamma counter; Solid scintillation detector; Liquid scintillation counter
Shielding material Lead; half-value layer = 0.41 cm
Dosimetry Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Always use the principles of time, distance and shielding to minimize dose.
  2. Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  3. Minimize handling time.
  4. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels.
  5. Use disposable absorbent liners on trays.

13.5 Tritium

H-3 Nuclide H-3 Decay

Radioactive half-life 12.35 years
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 18.6 keV
ALI    
  Ingestion 480 MBq/y
  Inhalation 490 MBq/y
Maximum beta range in the air 6 mm
Appropriate method for contamination monitoring Liquid scintillation counter
Shielding material Total absorption in <0.1 mm glass or plastic
Dosimetry Urine analysis for those that use 0.96 GBq (26 mCi) or more volatile liquids or gases at a time without containment

Special precautions:

  1. Tritium is not a radiation hazard unless it enters the body. Once in the body, tritiated water is uniformly distributed in the body water and can then expose tissues. Tritiated water can be absorbed through the surface of the skin, leading to internal exposure.
  2. Recommended protective clothing:
    1. Lab coat and PVC gloves (0.5 mm thick) are preferred because of this material’s low permeability to tritiated water.
    2. Many tritium compounds readily penetrate gloves and skin. Handle these compounds remotely, wear two pairs of gloves and change the outer layer at least every twenty minutes.
  3. Handle tritiated water, gases and volatile liquids in ventilated enclosures.
  4. Use glass containers to store tritium compounds because tritiated water and tritiated organic solvents will pass through plastic.
  5. Use disposable absorbent liners on trays.

13.6 Iodine-125

I-125 Nuclide I-125 Decay

Radioactive half-life 60.14 days
Decay mode e capture
Principal emissions gamma; X-rays
Gamma / X-ray energy 35.5 keV / 27 keV
ALI    
  Ingestion 1.3 MBq/y
  Inhalation 1.4 MBq/y
Appropriate method for contamination monitoring Gamma counter; Solid scintillation detector; Liquid scintillation counter
Shielding material Lead; half-value layer = 0.1 cm
Dosimetry

Thyroid scan for those who use in 24 hours more than 2 MBq (54 microCi) without containment or more than 200 MBq (5.4 mCi) in a fume hood. Radiation badge (whole body and ring) for those who use more than 50 MBq (1.35 mCi) at a time

Special precautions:

  1. Iodine compounds can become volatile. Handle and store in ventilated areas. Exposure to significant amounts of radioiodine increases the risk of developing thyroid cancer. Iodine is toxic by ingestion and inhalation and a strong irritant of eyes and skin. Iodine can be absorbed through the skin. When iodinated (I -125) albumin injection is heated to decomposition, radioactive fumes containing I-125 may be emitted.
  2. Recommended protective clothing:
    1. Disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Also wear safety glasses.
    4. Some iodine compounds can penetrate surgical rubber gloves. Wear two pairs of polyethene gloves over the rubber.
  3. Store NaI-125 solutions at room temperature because freezing may result in subsequent volatilization of radioiodine.
  4. The critical organ for I-125 uptake is the thyroid. The thyroid may be assumed to accumulate 30% of the soluble iodine and retain it with a biological half-life of 138 days. The elimination takes place via urine.

13.7 Indium-111

In-111

Radioactive half-life 2.83 days
Decay mode e capture
Principal emissions gamma; X-rays
Gamma energies 245.5 keV (100%); 171.3 (96%)
ALI    
  Ingestion 1.3 MBq/y
  Inhalation 65 MBq/y
Appropriate method for contamination monitoring Gamma counter; Solid scintillation detector; Liquid scintillation counter; Geiger-Muller
Shielding material Lead; half-value layer < 02 mm
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Indium metal and its compounds are toxic by inhalation, causing cumulative organ damage. Suspected teratogen. When Indium 111 chloride is heated to decomposition, radioactive fumes may be emitted.  
  2. Recommended protective clothing:
    1. Disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Also wear safety glasses.
  3. Keep handling time to a minimum. Always use the principles of time, distance and shielding to minimize dose.
  4. Use syringe shields and tongs.
  5. Use disposable absorbent liners on trays.

13.8 Potassium-42

K-42 Nuclide K-42 Decay

Radioactive half-life 12.36 hours
Decay mode beta – 100%
Principal emissions beta; gamma
Maximum beta energy 3.525 MeV
Gamma energies 1.524 MeV (100%); 1.922 MeV (22%); 2.424 MeV (16%)
ALI    
  Ingestion 47 MBq/y
  Inhalation 100 MBq/y
Maximum beta range in the air 13 m
Appropriate method for contamination monitoring Gamma counter; Solid scintillation detector; Liquid scintillation counter; Geiger-Muller
Shielding material Lead; half-value layer = 1.18 cm
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Always use the principles of time, distance and shielding to minimize dose.
  2. Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  3. Minimize handling time.
  4. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels. Use disposable absorbent liners on trays.
  5. Always handle hundreds of MBq quantities behind lead shielding.

13.9 Lutetium-177

Lu-177 Nuclide Lu-177 Decay

Radioactive half-life 6.73 days
Decay mode beta – 100%
Principal emissions beta; gamma
Maximum beta energy 498 keV
Gamma energies 208.3 keV (11%); 113 keV (6.4%)
ALI    
  Ingestion 29.6 MBq/y
  Inhalation 29.6 MBq/y
Maximum beta range in the air 93 cm
Appropriate method for contamination monitoring Solid scintillation detector; Liquid scintillation counter; Geiger-Muller
Shielding material Lead; half-value layer = 0.2 cm
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  • Always use the principles of time, distance and shielding to minimize dose.
  • Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  • Minimize handling time. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels.
  • Use disposable absorbent liners on trays.

13.10 Sodium-24

Na-24 Nuclide Na-24 Decay

Radioactive half-life 14.96 hours
Decay mode beta – 100%
Principal emissions beta; gamma
Maximum beta energy 1.39 MeV
Gamma energies 1.368 MeV (100%); 2.754 MeV (99.9%)
ALI    
  Ingestion 47 MBq/y
  Inhalation 38 MBq/y
Maximum beta range in the air 600 cm
Appropriate method for contamination monitoring Solid scintillation detector; Liquid scintillation counter; Geiger-Muller; Gamma counter
Shielding material Lead; half-value layer = 1.32 cm
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Always use the principles of time, distance and shielding to minimize dose.
  2. Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  3. Minimize handling time.
  4. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels.
  5. Use disposable absorbent liners on trays.

13.11 Phosphorus-32

P-32 Nuclide P-32 Decay

Radioactive half-life 14.26 days
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 1.71 MeV
ALI    
  Ingestion 8.3 MBq/y
  Inhalation 6.9 MBq/y
Maximum beta range in the air 7.9 m
Appropriate method for contamination monitoring Geiger-Muller; Liquid scintillation counter
Shielding material Total absorption: 3.4 mm glass or 6.3 mm Plexiglas
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Recommended protective clothing:
    1. Disposable plastic, latex or rubber gloves, safety glasses.
  2. Keep handling time to a minimum.
  3. Use plastic syringe shields and tongs to avoid direct skin contact.
  4. When possible work behind a plastic screen.
  5. Use disposable absorbent liners on trays.
  6. Always use the principles of time, distance and shielding to minimize dose.
  7. Near an unshielded 37 MBq (1 mCi) P-32 source, dose rates due to beta radiation can be 260 mSv/hr. Never work over an open container with P-32.
  8. Hundreds of MBq quantities can produce significant secondary radiation (x-rays) due to the bremsstrahlung effect. In this case, 3-6 mm of lead needs to be added to the Lucite shield. Avoid local high-dose exposure by remote handling of large quantities and prompt removal of contaminated clothing or gloves.

The bone is the critical organ for the uptake of transportable compounds of P-32. The lung and the lower intestine are the critical organs for inhalation and ingestion of insoluble P-32 compounds respectively.

13.12 Rubidium-86

Rb-86Nuclide Rb-86 Decay

Radioactive half-life 18.63 days
Decay mode beta – 100%
Principal emissions beta; gamma
Maximum beta energy 1.774 MeV
Gamma energies 1.077 MeV (100%)
ALI    
  Ingestion 7.1 MBq/y
  Inhalation 15 MBq/y
Maximum beta range in the air 790 cm
Appropriate method for contamination monitoring Geiger-Muller; Solid scintillation detector; Liquid scintillation counter; Gamma counter
Shielding material Plexiglas +Lead; half-value layer (lead) = 0.87 cm
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Always use the principles of time, distance and shielding to minimize dose.
  2. Recommended protective clothing:
    1. Use disposable plastic, latex or rubber gloves.
    2. Wear a lab coat, which must be monitored before leaving the laboratory.
    3. Wear safety glasses.
  3. Minimize handling time.
  4. Use syringe shields and tongs to handle unshielded sources and potentially contaminated vessels.
  5. Use disposable absorbent liners on trays.

13.13 Ruthenium-106

Ru-106 Nuclide Ru-106 Decay

Radioactive half-life 373.6 days
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 39.4 keV
ALI    
  Ingestion 2.96 MBq/y
  Inhalation 1.33 MBq/y
Maximum beta range in the air 8 mm
Appropriate method for contamination monitoring Liquid scintillation counter
Shielding material None
Dosimetry

Radiation badge whole body and extremities for those using 50 MBq (1.35 mCi) or more at a time

Special precautions:

  1. Recommended protective clothing:
    1. When working with unsealed sources wear appropriate protective clothing, such as laboratory coats, coveralls, gloves, and safety glasses/goggles.
    2. Laboratory coats must be monitored before leaving the laboratory.
    3. Use a suitable mask if the radioactive material is in the form of dust, powder or if it is volatile.

13.14 Sulphur-35

S-35 Nuclide-S-35decay

Radioactive half-life 87.44 days
Decay mode beta – 100%
Principal emissions beta
Maximum beta energy 167.5 keV
ALI    
  Ingestion 26 MBq/y
  Inhalation 170 MBq/y
Maximum beta range in the air 260 mm
Appropriate method for contamination monitoring Liquid scintillation counter
Shielding material Total absorption: 0.2 mm glass or 0.3 mm plastic
Dosimetry

Urine analysis for those that use 52 MBq (1.41 mCi) or more volatile liquids or gases at a time without containment

Urine analysis for those that use 52 MBq (1.41 mCi) or more volatile liquids or gases at a time without containment

Special precautions:

  1. Sulphur dioxide: irritant to eye, nose, throat, lungs; bronchoconstriction; mutagen, suspect reproductive effects. Hydrogen sulphide: moderate irritant to the eye (conjunctivitis), lung; acute systemic toxicity; Central Nervous System may be affected. Sulphur is combustible.
  2. Recommended protective clothing:
    1. Wear a disposable lab coat, gloves and wrist guards for secondary protection.
    2. Select appropriate gloves for chemicals handled.
    3. Lab coat must be monitored before leaving the laboratory.
  3. S-35 is volatile and should be handled in ventilated enclosures. Take care not to generate sulphur dioxide or hydrogen sulphide which could be inhaled.
  4. Use disposable absorbent liners on trays.
  5. Radiolysis of S-35 amino acids during storage and use may lead to the release of S-35 labelled volatile impurities. Therefore, all vials should be opened and used in a fume hood.

13.15 Technetium-99m

Radioactive half-life 6.01 hours
Decay mode IT (99.99%); beta (0.01%)
Principal emissions beta; gamma
Maximum beta energy 0.142 MeV
Gamma energies 0.140 MeV (89%)
ALI    
  Ingestion 910 MBq/y
  Inhalation 690 MBq/y
Appropriate method for contamination monitoring Liquid scintillation counter

Chapter 14: PERIODIC TABLE

Periodic Table of Elements

For information about some commonly used radionuclides at U of T, just click on the hyperlink (coloured) elements

H                                 He
Li Be                     B C N O F Ne
Na Mg                     Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba * Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra ** Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
Lanthanides series
* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu    
Actinides series
** Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr    

The information presented is considered adequate for the amounts usually used in the U of T laboratories. More information can be obtained at

https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html