Presentation on theme: "Radiation Safety Training ALARA Washington State University Radiation Safety Office."— Presentation transcript:
Radiation Safety Training ALARA Washington State University Radiation Safety Office
The Guiding Principle and Philosophy of Radiation Safety is: ALARA ( A s L ow A s R easonably A chievable) It is also a regulatory requirement!
So what does ALARA mean ? ALARA is an acronym for As Low As Reasonably Achievable. This is a radiation safety principle for minimizing radiation doses and releases of radioactive materials by employing all reasonable methods. ALARA is not only a sound safety principle, but it is also a regulatory requirement for all radiation safety programs.
What is the basis for ALARA ? Current radiation safety philosophy is based on the conservative assumption that radiation dose and its biological effects on living tissues are modeled by a relationship known as the Linear Hypothesis. The assertion is that every radiation dose of any magnitude can produce some level of detrimental effects which may be manifested as an increased risk of Genetic mutations and cancer.
RADIATION DOSE/RESPONSE MODELS Two models:(1) Linear 2) Threshold Preferred (Regulatory) model is Linear No-Threshold Dose Model: Conservative Hypothesis - For any dose, no matter how small, there is some effect, and as the dose is increased, the effect also is increased in proportion. Biological Response Dose Biological Response Threshold
How is ALARA Implemented ? An effective ALARA program is only possible when a commitment to safety is made by all those involved. This includes the Radiation Safety Office staff, the Radiation Safety Committee, research faculty and all radiation workers. The WSU Radiation ProtectionThe WSU Radiation Protection Program Manual Program Manual provides the guidelines for the Responsibilities and good practices which are consistent with both the ALARA concept and the regulatory requirements of the Washington State Administrative Code (Title 246 Chapter ).Title 246 Chapter ).
WSU radiation safety program. The WSU radiation safety program attempts to lower doses received by radiation workers by utilizing practical, cost effective measures.
How do we do this?
With the 4 basic Radiation Protection Principles. Time Distance Shielding Contamination Control
TIMEEXPOSURETIMEEXPOSURE Decreasing the amount of time near the source decreases your exposure.
How do you decrease your time exposure? Plan and Set Up Your Experiment Before Using Radioactive Materials. Perform Dry Runs - (Use NO Radioactive Material). Practice Handling Techniques (pipetting/aliquotting). Work Quickly but Safely.
DISTANCEEXPOSUREDISTANCEEXPOSURE Increasing the distance from the source decreases your exposure.
Increasing the distance from a source from 3 feet to 10 feet reduces the radiation intensity by 91%. Increasing the distance from a source from 3 feet to 32 feet reduces the radiation intensity by %. Increasing the distance from a source from 3 feet to 60 feet reduces the radiation intensity by %. Attenuation of Radiation Intensity with Distance
Inverse Square Law 1/(distance) I 1 (100 mR/hr) D 1 (1 meters) I 2 (?) D 2 (8 meters) Given:I 1 = 100 mR/hr D 1 = 1 meters D 2 = 8 meters I 2 =(d 1 ) 2 X I 1 (d 2 ) 2 =1.6 mR/hr If you double the distance from a point source of radiation, the exposure is reduced to ¼ the intensity at the closer distance.
SHIELDINGEXPOSURESHIELDINGEXPOSURE Increasing the amount of shielding decreases your exposure.
Proper thickness and appropriate materials are critical to shield you from a radiation hazard. Shielding Examples
SHIELDING Appropriate Shielding High "Z" Materials (Pb) for photons Low "Z" Materials (Acrylic or Plexiglas) for beta radiation Using Storage Containers (pigs) Shipping Containers from RAM Suppliers Using Local Shielding (Plexiglas L-Blocks & Pb - Bricks) Using Vial & Syringe Shields – Balance between shielding and time. (If it takes a long time to insert RAM into a shield it may not be ALARA!)
CONTROLLING EXTERNAL HAZARD TIME: Radiation dose is proportional to the duration of the exposure. DISTANCE: Radiation dose is proportional to 1/(Distance) 2. SHIELDING: Radiation dose is determined by the type and thickness of shielding materials used. Correct selection of Shielding Materials are a function of type and energy of radiation.
So how do we control the internal hazard?
By Contamination Control The major hazard for most radioactive materials on the WSU campus comes from internalizing the radioactive material. Once the radioactive materials are inside your body, you lose all the protections from TIME, DISTANCE AND SHIELDING. Contamination Control is the key to preventing internalization of radioactive materials.
Radionuclides can enter the body in four ways. Inhalation, ingestion, absorption through the skin and wounds.
Contamination Control Protect Yourself Always use protective clothing. Lab Coat Gloves Eyewear Required by WAC Lab Coats can be very fashionable. But always wear long pants and full shoes. The hat is optional. Dont dress like this guy! Wear gloves properly.
CONTAMINATION CONTROL Always WEAR your lab coat and gloves, including appropriate leg and foot covering. Required by WAC Wear safety glasses/goggles or a face shield when working with unsealed RAM. These precautions are especially important when there is a splash potential.
CONTAMINATION CONTROL (continued) CHANGE gloves frequently and REMOVE them when leaving the lab and dispose of them as radioactive waste. To control cross contamination of yourself, others and other research items.
Protect Others If you contaminate your lab partners. They will not be happy with you. Label your radioactive work area. Required by WAC
Protect Others (cont.) Label containers and tools used in radioactive work. Required by WAC
Contamination Control (cont.) Protect Facilities and Equipment Cover all radioactive work areas with absorbent paper, including any transfer trays or secondary containers. Required by WAC Check for Contamination (do surveys) Tape off the work area.
CONTAMINATION CONTROL (continued) Store and transport liquid radioactive materials in SECONDARY CONTAINERS, with the capacity to contain potential spills. - USE DOUBLE CONTAINMENT –
FOOD and DRINK NO eating, drinking, smoking, or chewing in the radioactive work space. (Internal contamination) Do not store food, drink or personal effects in any area, container, or refrigerator designated for radioactive materials use or storage. Required by WAC The presence of empty food and drink containers in the lab will constitute a violation of regulations, since it will be inferred that consumption occurred on the premises.
CONTAMINATION CONTROL (continued) NO mouth pipetting. (Internal contamination) Required by WAC MONITOR hands, clothes and work area frequently during and after each use. Always WASH hands at the completion of radioactive work.
ADDITIONAL RADIATION SAFETY PRECAUTIONS Work with volatile compounds in a CERTIFIED OPERATIONAL fume hood. The hood must also be labeled for radioactive materials use. - Operational parameters of the fume hood must be verified before you begin your radioactive work.
CONTROLLING INTERNAL HAZARD To minimize the uptake of radionuclides into the body control the Routes of Entry Inhalation:Use of fume hood, gloved boxes. Gases and vapors in experiments. Radioactive spill of volatile compounds. Opening of sealed vials. Ingestion:No eating, drinking, chewing, smoking or application of cosmetics in radioactive laboratories. Use of gloves (preferably double gloves). No food in radioactive refrigerators. Washing hands, do monitoring. Prohibit mouth pipetting. Absorption:Wear protective clothing (lab coat, full shoes; be aware of loose sleeves of lab coat).
On November 1, 2006, Alexander Litvinenko suddenly fell ill and was hospitalized.
He died three weeks later of polonium-210 induced acute radiation syndrome. The median lethal dose for polonium-210 is around 238 μCi or 50 nanograms in the case of ingestion. The polonium-210 was in his tea.
Polonium-210 is an alpha emitter. As we have seen in another module, alpha radiation is the highest internal hazard. If Mr. Litvinenko had not ingested the polonium it would not have been a radioactive hazard to him. The alpha radiation emitted by the polonium would not have penetrated the layer of dead skin on his body. So keep your lab clean. Do your surveys. NO eating, drinking, smoking, or chewing in the radioactive work space. Do not store food, drink or personal effects in any area, container, or refrigerator designated for radioactive materials use or storage.
Test Time! Follow this link to the test. https://myresearch.wsu.edu https://myresearch.wsu.edu Use your WSU user name and password to sign in. Click on the training tab. Then click on the available training tab Find the radiation safety training alara course, in the OR section, click on it and take the test.