University of Notre Dame Department of Risk Management and Safety Radiation Safety Training

Lesson 1 Forms of Radiation

Forms of Ionizing Radiation Ionizing radiation includes emissions with energies greater than 20 electron volts that cause ionizations when interacting with matter. Sources of ionizing radiation at Notre Dame include: Photon Radiation Gamma X-Ray Particulate Radiation Alpha Beta

Particulate Radiation ALPHA RADIATION Consists of two protons and two neutrons (helium nucleus) Massive size, moving at 80% the speed of light Internal Hazard BETA RADIATION Consists of an electron Very small size moving at up to 99% the speed of light Hazard depends on decay energy of isotope

Bremsstrahlung Radiation Literally: breaking radiation Electromagnetic radiation produced when an electrically charged particle is slowed down by the electric field of an atomic nucleus Example: The beta particle emitted by a P-32 atom will interact with lead to give off an x-ray Bremsstrahlung production must be considered when planning the shielding of high energy beta emitters e- X-ray

Lesson 2 Units of Radiation

Units of Radiation RAD The RAD is the unit commonly used in the United States for Absorbed Dose (D) It is determined by the Energy that is actually deposited in matter 1 Rad = 100 ergs of deposited energy per gram of absorber Gray International Unit for Absorbed Dose 1 Gray = 100 Rads

Units of Radiation REM The REM is the unit commonly used in the United States for the Dose Equivalent Determined by Multiplying the absorbed dose (D) times a quality factor (Q) Q equals 1 for beta, gamma and x-rays, 5-20 for neutrons, and 20 for alpha Sievert International Unit for absorbed dose 1 Sievert = 100 REM

Units of Radiation Most labs at Notre Dame will use only beta, gamma and/or x-ray emitters The Quality factor for these forms of radiation is equal to 1 Therefore the Rad is equal to the Rem If your lab is one of the few using alpha, remember that the QF is 20. Therefore, one Rad of alpha is equal to 20 Rem. Exposure reports are documented in mREM 1 REM = 1,000 mREM

Lesson 3 Biological Effects & Risk

Biological Effects Data is largely based on high exposures to individuals within the first half of the 20th century Biological effects occur when exposure to radiation exceeds 50 rads over a short period of time All occupational exposures are limited by city, state, or federal regulations

Radiation Damage Mechanical: Direct hit to the DNA by the radiation - Damages cells by breaking the DNA bonds Chemical: Generates peroxides which can attack the DNA Damage can be repaired for small amounts of exposure

Radiosensitivity Muscle Radioresistant Stomach Radiosensitive Bone Marrow Radiosensitive Human Gonads Very Radiosensitive

Radiation Effects Acute Effects: Nausea, Vomiting, Reddening of Skin, Hair Loss, Blood Changes Latent Effects: Cataracts, Genetic effects, Cancer

Lesson 4 Occupational Exposure

What are the Occupational Exposure Limits ? Whole Body Extremities Skin of Whole Body Lens of Eye Thyroid 5,000 mRem/year 50,000 mRem/year 15,000 mRem/year

Other Occupational Limits ALARA - As Low As Reasonably Achievable. This is our policy AND the NRC’s: Don’t expose yourself to radiation any more than absolutely necessary.

Exposure to the General Public Annual limit of 100 mRem to individuals This includes anybody in the laboratory who does not work for Notre Dame Examples: salesmen, vendors, family members, etc.

Prenatal Radiation Exposure In the embryo stage, cells are dividing very rapidly and are undifferentiated in their structure and are more sensitive to radiation exposure Especially sensitive during the first 2 to 3 months after conception This sensitivity increases the risk of cancer and retardation

Declaring Pregnancy Additional dose restrictions are available for the pregnant worker Receive a monthly dosimeter Limited to 500 mRem during the term of the pregnancy Also, limited to 50 mRem per month DECLARATION IS STRICTLY OPTIONAL

Exposure to Minors Individuals under the age of 18 Must not receive an exposure greater than 10% of occupational exposure for adults Wholebody Exposure Limit: 500 mRem Minors will wear dosimeters in laboratories licensed for radioactive material use Minors should not work with radioactive material

Lesson 5 Minimizing Exposure

How Do I Protect Myself? Reducing the dose from any source radiation exposure involves the use of three protective measures: TIME DISTANCE SHIELDING

Time The amount of exposure an individual accumulates is directly proportional to the time of exposure Keep handling time to a minimum

Distance The relationship between distance and exposure follows the inverse square law. The intensity of the radiation exposure decreases in proportion to the inverse of the distance squared Dose2 = Dose1 x (d1/d2)2

Shielding To shield against beta emissions, use plexiglass to decrease the production of bremsstrahlung radiation. If necessary, supplement with lead after the plexiglass To shield against gamma and x-rays, use lead, leaded glass or leaded plastic

Internal Exposure Only a few commonly used radionuclides at Notre Dame present an external exposure potential All radionuclides present a potential for internal exposure if taken into the body. Entry into the body can occur by inhalation, ingestion, or absorption through the skin

Minimizing Internal Exposure Wear personal protective equipment If required, use a fume hood No eating, drinking or applying cosmetics Clean up spills promptly Routinely monitor work area Secure radioactive material

Minimum Protective Equipment Laboratory coat Gloves Safety Glasses Dosimeters (for certain nuclides and/or machines)

Lesson 6 Radiation Detection

Detecting Radiation and Contamination Personal dosimeters are used to detect the occupational exposure to employees from external sources of radiation A survey meter may be used to detect large quantities of high energy beta and gamma emitters on a surface For smaller quantities of contamination on surfaces and low energy beta emitters, use the wipe test method

Film Badge Required when there is a possibility of receiving greater than 10% of exposure limit Monitors for gamma, x-ray and high energy beta Worn for 2 months These are individual specific - Do not loan out Return promptly after receiving a new one

Ring Dosimeter Monitors exposure to the hands Used for high energy beta, gamma and x-ray radiation Worn when handling sources like those listed above or x-ray machines Worn underneath the protective glove

Survey Instruments Geiger Mueller (G-M) - Detects alpha, beta, and gamma radiation - Best option for detecting beta contamination Sodium Iodide Detector - Gamma and x-ray only

Survey Instruments Operational Check Check calibration date Confirm calibration date within past year Check batteries Check response to radioactive source to confirm that the meter is operational

Survey Instruments Geiger-Mueller Detector Sodium-Iodine Detector Used for beta, gamma and x-ray emitters Best for P-32, S-35 and C-14 Will detect I-125 and Cr-51 Sodium-Iodine Detector Detects gamma and x-ray emitters I-125 and Cr-51 Do not use to detect beta emitters

Wipe Test Method The Wipe Test Method is a means of monitoring for small amounts of contamination It is the only method in the lab for detecting H-3 Wipe test surveys should include both areas where contamination is expected to be found and areas where it is not expected

Wipe Test Choose equipment and surfaces to wipe Use a filter paper or Q-tip to wipe approximately 100 cm2. Place filter paper or Q-tip in scintillation vial and add scintillation fluid (use enough fluid to fill at least ½ of vial) Place sample in scintillation counter Set scintillation counter to detect radioisotopes used in laboratory Include a standard or sample containing a known amount of radioactive material Include a background or control sample

Determining Activity of Wipes If the scintillation counter only provides results in counts per minute (cpm) it will be necessary to convert those results to disintegrations per minute (dpm). This can be done by including a control sample with your wipes that contains the isotope of interest. dpm = cpm / counting efficiency Standard (cpm) / Standard (dpm) = Efficiency 1 uCi = 2.22 X 106 dpm Decay of the standard’s activity must be considered.

Lesson 7 Contamination Control

Contamination Definition: Radioactive material in an undesired location Undesired locations: Surfaces, skin, internal, airborne Types: Removable – Decontamination is possible Fixed – Unable to decontaminate

Contamination Limits <20 dpm/100cm2 a in restricted areas <1,000 dpm/100cm2 b/g in restricted areas (radioisotope laboratories) >1,000 dpm/100cm2 b/g immediately clean up to below 1,000 dpm/100cm2

Contamination Control Work in areas designated for radioactive material Use absorbent pads Wear appropriate protective clothing Change gloves frequently Perform a dry run of the procedure without radioactive materials It is recommend that you set up well-defined, clearly labeled radioactive material work stations and restrict radioactive materials use to those areas

Spill Response Notify people working in the laboratory Control access to the affected area Wear gloves, lab coat, and safety glasses Clean spill from the outer perimeter inward Avoid spattering and generating aerosols After initial clean up, monitor for contamination Repeat process if contamination remains Call the RSO (1-5037) if you need help or if the spill is greater than 100 µCi

Decontamination of Skin If the radioactive material is a high energy beta, gamma, or x-ray emitter, monitor with a survey meter and record reading Gently wash the affected area for 15 minutes with lukewarm water and a mild soap If you continue to find contamination, repeat washing and monitoring for up to 3 times Record final survey meter readings Contact Radiation Safety at 1-5037

Lesson 8 Radioactive Waste

Radioactive Waste Disposal Minimize generation of waste Identify and segregate dry solid waste - long lived (H-3 and C-14) - - short lived (P-32 and S-35) Complete a waste form for pickup Keep disposal records

Do Not Mix Waste Types Do not place scintillation vials into dry solid waste containers Do not place dry solid waste into liquid scintillation vial waste Do not place liquid waste container into dry solid waste containers DO NOT MIX LONG AND SHORT HALF-LIVED WASTE (Break point = 89 days)

Holding Radioactive Waste for Decay Provide appropriate shielding for the waste Seal the container to prevent individuals from adding to the waste Label the waste container with the isotope, amount of radioactive material, and date the container was sealed Hold for 10 half-lives. This will be done by RM&S.

Radioactive Waste Containers DO NOT dispose of radioactive waste in: - medical waste containers - general waste Use only approved radioactive waste containers supplied by Radiation Safety which contains a warning label “Caution Radioactive Material”

Scintillation Vials Place in a separate container from the dry solid radioactive waste Separate scintillation vials containing long lived isotopes (H-3 and C-14) from those containing shorter lived isotopes (P-32, I-125) Ensure the lids are secured tightly on the bottles Do not overfill the container Complete a Radioactive Waste Form

Contaminated Sharps Syringes Pasteur Pipettes Scalpel Needles Radioactive sharps must be segregated from other radioactive waste and placed in a radioactive materials labeled sharps container.

Collecting Liquid Use a durable carboy from RM&S Attach a radiation warning label to the bottle Document the isotope, activity and date on the container Secure the lid on the container at all times NEVER POWER IT DOWN THE LAB SINK

Lesson 9 Clearing Equipment

Clearing Equipment For repair by Engineering or Vendor: Ensure equipment is empty of all samples, containers, and radioactive material Conduct wipe test and present results to RSO Monitor with survey meter Decontaminate equipment if required

Telephone Numbers Radiation Safety: 1-5037 Fax: 1-8794 Risk Management & Safety website: www.riskmanagement.nd.edu After hours, weekends, holidays: Call ND Security 1-5555