Basic Radiation Safety Awareness Training Radiation Safety

Basic Radiation Safety Awareness Training Radiation Safety Program 713-500-5840 Environmental Health and Safety

Outline History of Radiation Natural & Man-Made Background Sources of Radiation Fundamentals Exposure Limits & Regulations Detection of Radiation Safe Practices with Radiation Biological Effects of Radiation Where to Find Further Information

First Known Human Use of Uranium 79 A D Roman artisans produce yellow colored glass in mosaic mural near Naples, Italy

Radium Effects Confirmed 1925 Suspicions develop around watch dial painters’ jaw lesions Dentists diagnose lesions as jaw necrosis due to radium deposits in jaw bone Doctor notes bone changes and anemia in dial painters

What is Radiation? Radiation: energy in motion Radioactivity: spontaneous emission of radiation from the nucleus of an unstable atom Isotope: atoms with the same number of protons, but different number of neutrons Radioisotope: unstable isotope of an element that decays or disintegrates spontaneously, emitting radiation. Approximately 5,000 natural and artificial radioisotopes have been identified

Types of Radiation Non-Ionizing Radiation: Radiation that does not have sufficient energy to dislodge orbital electrons. Examples of non-ionizing radiation: microwaves, ultraviolet light, lasers, radio waves, infrared light, and radar. Ionizing Radiation: Radiation that has sufficient energy to dislodge orbital electrons. Examples of ionizing radiation: alpha particles, beta particles, neutrons, gamma rays, and x-rays.

Radiation Spectrum

RADIOACTIVE SOURCES Cosmic Rays Solar Radiation Nuclear Medicine X-Rays Radon Consumer Products Each Other Radioactive Waste Terrestrial Radiation Food & Drink Nuclear Power

Terrestrial Radiation Terrestrial radiation comes from radioactivity emitting from Primordial radio nuclides - these are radio nuclides left over from when the earth was created. Common radionuclides created during formation of earth: –Radioactive Potassium (K-40) found in bananas, throughout the human body, in plant fertilizer and anywhere else stable potassium exists. –Radioactive Rubidium (Rb-87) is found in brazil nuts among other things.

Terrestrial Radiation Greatest contributor is 226Ra (Radium) with significant levels also from 238U, 232Th, and 40K. Igneous rock contains the highest concentration followed by sedimentary, sandstone and limestone. Fly ash from coal burning plants contains more radiation than that of nuclear or oil-fired plants.

Let’s Compare Backgrounds Sea level - 30 mrem/year from cosmic radiation 10,000 ft. altitude - 140 mrem/year from cosmic radiation

Consumer Products and Radioactive Material There are more sources of radiation in the consumer product category than in any other. Television sets - low energy x-rays. Smoke detectors Some more products or services: treatment of agricultural products; long lasting light bulbs; building materials; static eliminators in manufacturing; and luminous dials of watches, clocks and compasses

Annual Dose from Background Radiation Total exposure Man-made sources Medical X-Rays 11% Radon 55.0% Other 1% Internal 11% Cosmic 8% Man-Made 18% Terrestrial 6% Nuclear Medicine 4% Consumer Products 3% Total US average dose equivalent 360 mrem/year

The Anatomy of the Atom

Ionizing radiation Occurs from the addition or removal of electrons from neutral atoms Four main types of ionizing radiation alpha, beta, gamma and neutrons Alpha n Beta Gamma (X-ray) Neutron

Linear Energy Transfer

ALARA As Low As Reasonably Achievable How? Time Distance Shielding Why? Minimize Dose

Time Less time Less radiation exposure Use RAM only when necessary Dry runs (without radioactive material) Identify portions of the experiment that can be altered in order to decrease exposure times Shorten time when near RAM Obtaining higher doses in order to get an experiment done quicker is NOT “reasonable”!

Distance Effective & Easy Inverse Square Law Doubling distance from source, decreases dose by factor of four Tripling it decreases dose nine-fold More Distance Less Radiation Exposure Tongs, Tweezers, Pipettes, Pliers

Shielding Materials “absorb” radiation Proper shielding Less Radiation Exposure Plexiglass vs. Lead

Shielding Examples

Radiation Shielding Shielding used where appropriate Significantly reduces radiation effects Plexiglas Lead

Radiation Postings Radiation use will be labeled on door, work area & storage area Research laboratories work with very low levels of radioactive materials Safety can check for potential contamination prior to work in a lab that uses radioactive materials As a precaution: wear gloves, safety glasses and wash

Inappropriate Lab Attire

Appropriate Lab Attire Lab coat Eye protection Closed toe shoes Personnel monitoring Gloves

Route of Entry for Exposure

Laboratory Wipe Tests Fill out form RS-8 Draw map of laboratory Take wipes of surfaces (10 cm2) throughout lab Run wipes monthly for possible contamination Document all information on form and place in Radiation Safety Binder

Common Units Radioactivity Exposure Absorbed Dose Dose Equivalent Units are Cool

Radioactivity Rate of Decay / Potential to Decay “Strength” Curie (Ci) - 1 gram of radium disintegrates 3.7 X 1010 disintegration/ second (dps) Becquerel (Bq) 1 disintegration/second (dps) 1 mCi 37 MBq

Exposure Radioactivity is measured in Roentgens (R) Charge produced in air from ionization by gamma and x-rays ONLY for photons in air Rather infrequently used unit A measure of what is emitted

Absorbed Dose Energy deposited by any form of ionizing radiation in a unit mass of material Roentgen Absorbed Dose (rad) Gray (Gy) 1 Gy 100 rad

Dose Equivalent Scale for equating relative hazards of various types of ionization in terms of equivalent risk Damage in tissue measured in rem (Roentgen Equivalent Man) Q:risk of biological injury rem Q * rad Sievert (Sv) 1 Sv 100 rem

What do we really need to know? 1 R 1 rad 1 rem For gammas & betas* 1 rad 1 rem For alphas, neutrons & protons 1 rem 1 rad * Q

And why do we want to know it? Dosage and dosimetry are measured and reported in rems. All the Federal and State regulations are written in rems. The regulators must be placated with reports in rems.

Annual Radiation Exposure Limits Occupationally Exposed Worker: rem mrem Whole body 5 5000 Eye 15 15,000 Shallow 50 50,000 Minor 0.5 500 Pregnant Worker 0.5* 500* *9 months General Public: 100 mrem/year or 2mrem/hour

Why Establish Occupational Exposure Limits? We want to eliminate ability of non-stochastic effects (Acute) to occur Example: Skin Reddening We want to reduce the probability of the occurrence of stochastic effects (Chronic) to same level as other occupations Established Example: Leukemia from Accident Data

Whole Body Total Effective Dose Equivalent (TEDE) TEDE Internal External Assume Internal Contribution Zero Unless Ingestion, Absorption or Inhalation Suspected Limit 5 rem / yr

Ensuring Compliance to Radiation Exposure Limits Use the established activity limit for each isotope Compare with similar situations Estimate with meter Calculate Time, Distance, Shielding, Type, Energy, Geometry Measure TLD Chip, Luxel Bioassay

Who should wear radiation dosimeters or badges? Those “likely” to exceed 10% of their annual limit are required Those who would like a badge Minors & Declared Pregnant Workers*

Types of Badges Available

Rules, Rights & Responsibilities as a Radiation Worker Department of State Health Services Radiation Control Texas Regulations for Control of Radiation In Accordance with Texas Radiation Control Act, Health & Safety Code, Ch 401 25 TAC (Texas Administrative Code) 289

Detection of Radiation

Radiation Detectors General Classes of Detectors Gas-Filled Detectors Solid Detectors Liquid Detectors

Gas-Filled Detectors Proportional Counter Ion Chambers Geiger-Mueller Counters Main Difference Charge Multiplication

Liquid Scintillation Counter (LSC)

More Radiation Misconceptions Radiation does not give you super human powers Radiation will not make you glow in the dark

Summary of Biological Effects of Radiation Radiation may Deposit Energy in Body Cause DNA Damage Create Ionizations in Body Leading to Free Radicals Which may lead to biological damage

Radiation Effects on Cells Radio sensitivity Theory of Bergonie & Tribondeau. Cell are radiosensitive if they : Have a high division rate Have a long dividing future Are of an unspecialized type These are the underlying premise for ALARA

Response to radiation depends on: Total dose Dose rate Radiation quality Stage of development at the time of exposure

Whole Body Effects Acute or Nonstochastic Occur when the radiation dose is large enough to cause extensive biological damage to cells so that large numbers of cells die off. Evident hours to a few months after exposure (Early). Late or Stochastic (Delayed) Exhibit themselves over years after acute exposure. Genetic Somatic Teratogenic

Most and Least Radiosensitive Cells Low Sensitivity Mature red blood cells Muscle cells Ganglion cells Mature connective tissues High Sensitivity Gastric mucosa Mucous membranes Esophageal epithelium Urinary bladder epithelium Very High Sensitivity Primitive blood cells Intestinal epithelium Spermatogonia Ovarian follicular cells Lymphocytes

Comparison of Administrative, Regulatory and Biological Effect Doses Partial Body Exposure Whole Body Exposure Rad or Rem Molecular Death ( 100,000 rad) 100% of People Die, CNS Syndrome Ulcers on the Skin Skin Reddening Gastrointestinal Syndrome Cataract Formation 50% of People Die (450 – 500 rad) Permanent Infertility Nausea & Vomiting (10% of People) Loss of Hair Extremities Regulatory Limit (50 rem/yr) Eye Regulatory Limit (15 rem/yr) Extremities UTHSCH Administrative Limit (1.275 rem/month) Eye UTHSCH Administrative Limit (0.375 rem/month) Decreased White Blood Cell Count No Clinical Symptoms Seen Below 10 rem Whole Body Regulatory Limit (5 rem/yr) Whole Body UTHSCH Administrative Limit (0.125 rem/month) General Public Whole Body Regulatory Limit (0.100 rem/yr)

Medical Treatment External Decontamination Mild cleaning solution applied to intact skin Betadine, Soap, Rad-Con for hands Never use harsh abrasive or steel wool Internal Decontamination Treatment which enhances excretion of radionuclides

How Often Does This Happen? Results of reported exposure-related incidents in Texas 1956 – 2000 Source: Emery, et. al. Only 2% at the Level that Clinical Effects From Radiation Can be Seen (n 3,148)

Where to Find More Radiation Safety Information . Basic Radiation Safety Training (6-hr) Required for All Individuals Working with Radiation July 11 & 12th – 9 a.m. to Noon (both days) Call at 713-500-5840 Website www.uth.tmc.edu/safety Radiation Safety Manual Important Safety Information Posted in Every Laboratory (Yellow)