Radiation Safety Guide
Radiation Protection Services (RPS) has the responsibility to implement the radiation safety program at Stony Brook University. The complete rules and regulations for the safe use of radioactive materials can be found in the University Radiation Protection Committee (URPC) Policies and Procedures booklet, which is available in each authorized radioactive materials laboratory. This booklet is provided to aid you in recognizing your responsibility for radiation safety. While it gives an overview of basic radiation safety procedures, it is the responsibility of each radiation worker to be thoroughly familiar with all applicable sections of the Radioactive Materials Safety Manual.
Please click one of the following links to navigate throughout this guide:
- Authorization to Use Radioactive Materials
- Ordering and Receiving Radioactive Materials
- Radiation Protection Procedures
- Radioactive Material Surveys
- Radioactive Material Survey Procedures
- Removable Contamination Limits
- Radioactive Waste Disposal
- Personnel Dosimetry
- Pregnant Workers
- Radioiodine Exposure Monitoring
- Accidental Spills of Radioactive Material
- View Entire Guide
Authorization to Use Radioactive Materials
All radioactive materials users must be authorized through the RPS office. Senior Investigator authorizations are granted to qualified individuals who are principle investigators of research projects and/or responsible for supervising radioactive materials used by associate users or students in the lab. Associate Investigator authorizations are granted to those individuals working under the supervision of and directly responsible to a Senior Investigator. Radioisotope laboratories must be approved and their use restricted to those isotopes and conditions listed in the Radioactive Materials Authorization.
Ordering and Receiving Radioactive Materials
All radioisotope orders must be approved by RPS and delivered to the RPS office. Quantities ordered may not cause the laboratory inventory to exceed authorized limits. All withdrawals of radioisotopes from original containers must be logged on the Inventory/Disposal sheets provided by RPS. When containers are empty they are discarded to waste and the Inventory/Disposal Record sheet returned to the RPS office.
Radiation Protection Procedures
When working with radioactive materials or radiation sources, each worker should be aware of the methods or procedures that can best be used to reduce his or her radiation exposure. To limit exposure from external radiation, one can reduce the time spent with the material, increase the distance between the material and the body, or interpose shielding between the source and the body. For prevention of intake of radioactive material that could lead to internal exposure, one should minimize the amount of material handled, make sure the material is properly contained, wear appropriate protective clothing (i.e., lab coats, gloves, boots, respirators, etc.), and follow established procedures as outlined below.
Radioactive Materials Area Protection Procedures:
- Eating, drinking smoking, use of cosmetics or storage of food and beverages is prohibited except in specific designated areas which are approved by RPS.
- Radioactive Materials Areas must be locked when unattended unless all radioactive materials are otherwise secured.
- No items shall be removed from areas where a reasonable possibility exists of its being contaminated until monitored and found free of contamination.
- No mouth pipetting is allowed in Radioactive Materials Areas.
- Label all containers of radioactive materials. Labels shall include date, nuclide, quantity, the words CAUTION-RADIOACTIVE MATERIALS, and the radiation symbol. This need not include laboratory containers, such as beakers, flasks and test tubes, used transiently in laboratory procedures.
- Radioactive material work areas should be non-porous and/or covered with backed absorbent paper.
- All stored material shall be placed in a designated and posted secure location. Shielding shall be provided to reduce radiation levels to less than 5mR/h at the surface.
- Any operation with amounts of radioactive materials which can cause a radiation hazard, if the operation dose not proceed according to plan, shall be preceded by a sufficient number of rehearsals without radioactive material to ensure that the operation will be reasonably free of incidents.
- Fume hoods used for manipulations or storage of any radioactive materials must have a face velocity of 100 linear feet per minute or greater.
Personnel Protection Procedures:
- Protective clothing and gloves shall be worn when handling radioactive material under conditions where contamination may be expected.
- Personnel with breaks in the skin should use waterproof tape to seal such breaks or not manipulate radioactive materials.
- Personnel should monitor themselves for contamination at frequent intervals when working with radioactive materials. Monitoring should include hands, body, hair, shoes and clothing. If contaminated, the body and clothing shall be decontaminated before leaving the area.
Radioactive Material Surveys
Surveys for radiation and radioactive contamination must be performed after each use of radioactive material. The purpose of this survey is to identify any contamination present and to prevent its spread. This survey need not be recorded.
A formal survey for radioactive contamination and radiation levels (if appropriate) must be performed and recorded on forms provided by the RPS office at latest once in each month that radioisotopes are handled, or at such other times or intervals as specified by RPS. For periods in which no radioisotopes are handled, no survey is required. However, a notation to this effect must be made either on the survey form or other suitable written record.
Radioactive Material Survey Procedures
The most common survey procedure to detect the presence of loose contamination is called a wipe test. In this procedure, a piece of filter paper (usually about 1 square or circular) is used to wipe over a surface suspected of being contaminated. The area which the wipe should cover is approximately 100 square centimeters. Depending on the surface being wiped or the type of material being surveyed for, it may be necessary to wet the wipe material with alcohol or other solvent for better adhesion of contaminated particles to the wipe. Wipe samples should include your working areas, floor space near your working areas, waste container areas and storage areas.
Analyze the wipe samples, using an appropriate instrument. Beta-emitting isotopes below 200 keV should be analyzed using a liquid scintillation or counting system. Wipe samples of gamma or x-ray emitters should be analyzed using a gamma counting system. Record on the survey diagrams the maximum contamination levels found as well as the final levels.
Portable survey instruments can also be used to survey for contamination. Geiger (GM) counters with thin window probes can be used to detect beta emitting isotopes with energies above 70 keV. Where gamma emitting isotopes are used, a survey instrument with a sodium iodide (NaI) probe should be used.
Before using any instrument, become familiar with its proper operation. To perform a survey using a potable instrument, scan the area suspected of being contaminated with the instrument's probe. To prevent possible contamination of the probe, do not let it touch the surface being surveyed. Any contamination found should be tested for removable contamination.
Removable Contamination Limits
All removable contamination shall be kept as low as reasonable achievable. Items or areas that could come in contact with skin or personal clothing must always be decontaminated until undetectable. Whenever measurable contamination remains on skin or clothing, notify RPS.
For removable contamination greater than 500 dpm per 100 cm2, the item or area must be cleaned up to the lowest practical levels within 1 working day. "Lowest practical level" means that level at which the risk from the contamination hazard is minimal. For example, labeled items in designated work areas should be decontaminated to less than 500dpm/100cm2. Items that could be used in uncontrolled areas (i.e. an internally contaminated centrifuge to be transferred to the shop for repair) must be cleaned until no contamination is detectable.
Removable contamination greater than 1000dpm per 100cm2 must be decontaminated to the lowest practical levels at once. Such contaminated incidents must be reported to RPS within one working day. RPS will perform a follow up survey to ensure proper decontamination.
Radioactive Waste Disposal
Current instructions for disposal are provided on each of the types of waste containers supplied on request by the RPS. These instructions must be followed carefully and pertain to the most up-to-date information as supplied to RPS from the waste burial sites. Each deposit in a container must be logged on the container's contents sheet. Techniques that can be used to minimize waste volume are:
- Separate "exempt" (liquid scintillation media containing less than 0.05m Ci/g H-3 and C-14) waste from other wastes generated.
- Be certain that just radioactive waste is placed in RPS containers. If in doubt, a wipe survey or instrument survey of the item can determine if the material is radioactive. Also, if only a small area of an item (lab bench soaker, for example) is radioactive, dispose of only the contaminated portion to radioactive waste.
- Waste containing short-lived radioisotopes such as P-32 or I-125 can be stored until decayed. Several "Decay in Storage Areas" have been designated on campus for this purpose if storage in the laboratory poses a problem.
Personnel dosimetry (whole body badges and ring badges) are issued to individuals based on the type and amount of radioactive materials being used, as indicated on the Investigator's application for authorization. Please note that most personnel dosimeters cannot detect the presence of low energy beta particles, such as those emitted from Hydrogen-3, Carbon-14 and Sulfur-35. Personnel using only such isotopes do not need dosimeters.
Badges are changed on a monthly basis. A radiation exposure report is provided to you at the time the badges are changed. You are advised to review this report to monitor any exposure you may have received.
General Rules for Personnel Dosimeter Use:
- Wear your body dosimeter(badge) between the waist and neck level. If, however, one area of the body is more likely to be exposed than the rest, the dosimeter should be worn in that area. Wear your ring badge (if issued) on the inside of your protective gloves, with the label turned to the inside of your hand. Double glove your badge hand to prevent ripping of the plastic glove by the ring badge.
- Clip the dosimeter to your clothing so that the front stays upright and faces away from your body. Never allow clothing such as lapels, neck ties, buttons, or other items to shield the front of the dosimeter.
- A badge must be worn only by the person to whom it is issued.
- Badges should be protected against damage by heat, moisture, or pressure.
- Badges must not be worn during non-occupational exposure, such as during treatments with medical and dental X-rays.
- When not is use, badges should be stored along with the "control" badge on the racks provided. The control badge is used to monitor any radiation the badges on the account receive whenever they are not worn, such as during transit to and from the vendor.
- RPS should be notified whenever an individual's personnel dosimeter is no longer needed.
It is the responsibility of each woman working with radioactive materials to notify in writing both her supervisor and RPS of her pregnancy as soon as she becomes aware of the pregnancy. The RPS information booklet Possible Health Risks to Children of Woman Who are Exposed to Radiation During Pregnancy is available upon request.
Radioiodine Exposure Monitoring
Radioiodine exposure monitoring is accomplished by thyroid bioassay. Such monitoring will be accomplished whenever an investigator uses a quantity of I-125 or I-131 at any time which equals or exceeds 100m Ci. The investigator shall notify RPS of such use so that arrangements for a bioassay within 72 hours may be made.
Accidental Spills of Radioactive Material
All spills of radioactive material must be cleaned promptly. The responsibility for cleaning up the spill rests on the individuals working in the area involved and responsible for the spill. Under no circumstances should an untrained person attempt to examine or clean up a spill of radioactive material. If assistance is needed, contact the RPS Office.
Major spills, such as contamination of the body or clothing, ingestion of radioactive material, overexposure to radiation, etc. shall be decontaminated under the direct supervision of RPS.
Minor spills, those involving little or no radiation or contamination hazard to personnel may be decontaminated by laboratory personnel under supervision of the responsible Senior Investigator or his designee.
The following general procedures should be followed when dealing with spills of radioactive materials:
- Inform others of the spill. Adjust your response to the seriousness of the spill. Instruct those personnel present in the room at the time of the spill to remain in an evacuation area to prevent contamination spread. Have an evacuee notify the RPS office of the incident. If after normal working hours, report the incident to Public Safety. Evacuated personnel should not eat, drink or smoke until they are monitored and found free of contamination.
- Affected persons should limit their movement to confine the spread of contamination.
- Contain the spill from further spread. If the material is a liquid, place an absorbent material such as paper towels, tissues, cloth, etc. over the spill to prevent its spread. If the material spilled is a powered solid, attempt to contain its spread by covering the area with a protective barrier such as a drip tray, empty beaker, section of paper, etc. If appropriate, close doors and windows, and turn off room ventilation fans.
- Remove contaminated clothing at once; flush contaminated skin areas thoroughly.
- Shut off ventilating equipment (if possible) that may transport contaminated air from the area to other parts of the building.
- Vacate and post or cordon off the contaminated area.
- Assemble in a nearby safe or clear area and begin monitoring and decontamination of affected persons. Do not leave the area unless adequately decontaminated or with the permission of RPS.
- Decontaminate the area: Plan ahead. Provide adequate protection and supplies for personnel involved in the clean up. Begin at the periphery and work toward the center of the contaminated items in the proper waste containers.
- Monitor the area: Using appropriate survey techniques, monitor the progress of the decontamination. Monitor all personnel and material before releasing them to clean areas.