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Radiation Safety


Radiation Safety Policies


The Radiation Safety Committee has approved the following policies regarding the use of radioactive materials:

Eating & Drinking in Radioisotope Laboratories (adopted 6/03) (top)

Eating, drinking, or other similar activities (consuming medicines, applying cosmetic products, etc.) in rooms labeled as radioisotope use areas is not permitted except under the following conditions:

  • Any area in which eating and drinking occur must be designated as an Eating/Drinking Area. The Radiation Safety Committee must grant specific approval to an Authorized User to designate an area to be an Eating/Drinking Area. The Committee will take into account the nature of the radioisotope activities in the lab before approving an Eating/Drinking Area, e.g., a laboratory using Na^125 I may not be granted approval.
  • Laboratories in which use or storage of state-licensed radioactive materials occurs cannot contain spaces designated as Eating/Drinking Areas.
  • In general, there must be a minimum separation of 5 feet between any locations in which radioactive materials are used or stored and an Eating/Drinking Area. However, the Committee may allow smaller separations if the Committee determines that factors such as the presence of walls or other physical barriers or the nature of the radioactive source (e.g., a sealed source) will prevent contamination from readily spreading into the Eating/Drinking Area.
  • An Eating/Drinking Area must be designated with signage stating “Eating/Drinking Area - No radioactive materials are permitted within this area.”
  • Radioisotope work and storage areas must be designated with signage, tape, or other labeled barriers to indicate that radioactive materials are stored or used beyond this point.
  • Laboratory personnel must remove gloves and wash and survey hands after working with radioisotopes, and prior to entering an Eating/Drinking Area.
    A waste receptacle must be provided within the Eating/Drinking Area and used only for non-laboratory trash.
  • If the layout of the lab is such that it is necessary to carry food or beverages to the Eating/Drinking Area by passing through the radioisotope use area, it is not permitted to eat or drink while passing through the radioisotope use area, and personnel carrying food or beverages must pass through the radioisotope area without lingering.
  • EHS shall conduct spot checks for contamination within and at the boundary of Eating/Drinking Areas as part of its routine laboratory surveys.
  • Permission for an Eating/Drinking Area within a laboratory will be revoked if EHS finds radioactive material or contamination within an Eating/Drinking Area or if violations of these requirements are observed.

Protective Clothing for Radioisotope Users (top)

Gloves, a full-length laboratory coat, and closed-toe shoes, are required to be worn by any person working with an open radioactive source in an amount equal to or exceeding 0.01 times the quantity given in Appendix C of the Radiation Safety Guide for any radioisotope, if such work creates a reasonable potential for contamination. For the most commonly used isotopes, these quantities are 1 µCi for C-14, 10 µCi for H-3, 0.01 µCi for I-125, 0.1 µCi for P-32, and 1 µCi for S-35. However, it is recommended that appropriate protective clothing, including gloves, a full-length laboratory coat, and closed-toe shoes should be worn at all times for work with any open radioactive source, regardless of the source activity. Wearing sandals or open-toed shoes, when handling the quantities specified above, is prohibited.

Security of Radioactive Materials (top)

All radioactive stock materials and sealed sources must be stored in a secured container or secured storage area when not in use. Any room in which an unattended sealed source is being used must be secured. Exceptions must be approved in writing by the Office of Environmental Health and Safety. A stock material is defined to be radioactive material as provided by the vendor and does not include material withdrawn from the original stock by a researcher for experimental use. This policy applies to materials for which EHS approval and authorization is required and does not apply to generally-licensed devices, such as smoke detectors, static eliminators, electron capture detectors, exit signs, etc.

Training for Personnel in Radioisotope Laboratories (top)

All researchers working in a laboratory in which open sources of radioactive materials are used must complete initial and refresher radiation safety training. The requirement applies to all researchers in an Authorized User's lab, even those who do not use radioactive materials and are not likely to enter the radioisotope area. This applies whether or not the individual has attended previous radiation safety training sessions elsewhere.

Researchers who handle sealed or plated radioactive sources only must complete initial radiation safety training for sealed source users.

Transferring Radioisotopes between Princeton University Laboratories (adopted 2/04)(top)

Transfers of radioactive materials between Princeton University Authorized Users are permitted under the following conditions:

  • Transfers of sealed sources or plated sources are not permitted without written authorization from EHS.
  • Transfer of open sources are permitted under the following conditions:
    • The lab which originally possesses the material (the transferring lab) is responsible for ensuring that the lab asking to receive the material (the recipient lab) is authorized to possess the radioisotope in question, prior to the transfer.
    • In order to determine whether the recipient laboratory is appropriately authorized, the transferring laboratory may either contact EHS to inquire about the recipient laboratory’s authorization prior to the transfer or the transferring lab may follow the EHS web-based procedure for verifying the recipient’s lab’s authorization and for sending e-mail notification of the transfer to EHS. If the transferring laboratory uses the web-based procedure, prior notification to EHS and prior approval by EHS of the transfer is not required.
    • The transferring lab must make a notation on the original Vial Use Log indicating that the transfer has occurred.
    • When appropriate (for example, when an entire vial is being transferred), EHS will make the appropriate inventory adjustments and will provide the recipient lab with a new Vial Use Log for the transferred vial.
    • Transfers must comply with requirements for transporting materials, as described in the Princeton University Radiation Safety Manual.


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