SECTION 2: Using Radioisotopes Safely

• Protective Clothing
• Food and Beverages
• Mouth Pipetting
• Security
• Signs and Labels
• Fume Hoods and Biosafety Cabinets
• Biological and Chemical Hazards
• Keeping Radiation Exposure ALARA

In some cases the practices described below are required by regulation or by license conditions but in all cases these practices represent good laboratory practices which will promote the safe use of radioactive materials.

Protective Clothing (top)

Lab accidents often involve spills or splashes which can readily contaminate exposed wrists, legs and feet. For any work with an open radioactive source, wear:

• gloves (the longest length available)
  
• a full-length lab coat (worn closed with sleeves rolled down)
  
• close-toed shoes. Do NOT wear sandals or other open-toed shoes while working with radioactivity

It is strongly recommended that you wear safety glasses for any procedure, but it is essential that you war safety glasses whenever there is a potential for the build-up of pressure.

Keep an extra set of clothing and shoes in the lab in the event that clothing becomes contaminated.

Avoid using petroleum-based hand creams when wearing gloves because petroleum-based hand creams may increase glove permeability.

Food and Beverages (top)

• Do not eat, drink or smoke in any room in which open sources of radioactive materials are used.
  
• Do not store food, beverages, or medicines in refrigerators, freezers or coldrooms where open sources of radioactive materials are used or stored.
  
• Do not store food, beverages, medicines, cosmetics, coffee cups, eating utensils, etc. on open surfaces near lab benches where contamination can be
  readily spread.

Mouth Pipetting (top)

Never mouth pipet radioactive solutions.

Security (top)

• Lock radioactive stock materials and sealed sources in a secured container or a secured storage area when not in use. A stock material is radioactive material as provided by the vendor and does not include material withdrawn from the original stock for experimental use.
• Do not leave radioactive materials unsecured in an unattended lab, even for a short time, unless the lab is locked.
• Supervise visitors to the lab.
• When visitors who are not accompanied by authorized lab personnel enter the lab, find out who they are and why they are there.
• If you discover that radioactive material is missing or lost and cannot be accounted for, notify EHS no later than the next business day.

Signs and Labels (top)

For the radioisotopes commonly used at Princeton University, labeling of rooms and containers is mandatory under the following conditions:

• Labeling Contaminated items and containers of radioactive material is an important tool for contamination control and is a courtesy to other laboratory personnel.
• Any container of radioactive material, any room or piece of equipment in which radioactive material is stored and any contaminated area or item,regardless of the level of radioactivity, should be labeled as Radioactive.
• Radioactive Material tape is available from the Molecular Biology Department and Chemistry Department stockrooms.

Fume Hoods and Biosafety Cabinets (top)

Work with certain radioactive materials, such as volatile I-125 or millicurie amounts of S-35 methionine/cysteine, must be performed in a designated radioactive materials (RAM) fume hood. A RAM hood must be:

• Posted with an Environmental Health & Safety (EHS) RAM sticker, and a Class A or a Class B hood. For radioiodine work, a RAM hood must be a Class A hood with an average face velocity of at least 100 lfpm. The hood class is shown on the EHS hood survey sticker.
• To verify that the hood is functioning properly, compare the current reading for the hood’s continuous flow monitoring device (e.g., magnehelic) with the expected reading shown on the EHS hood survey sticker.
• Biological safety cabinets (or laminar flow hoods) may not be suitable for radioisotope work, since the air from the cabinet may be exhausted back to the room. Consult with EHS before performing work with volatile radioactive materials in a biological safety cabinet.

Biological and Chemical Hazards (top)

In addition to radiation hazards, some experimental protocols may pose biological and chemical hazards as well. Be familiar with all the risks associated with an experiment, follow any necessary precautions, and know the proper disposal techniques for the resulting wastes.

Keeping Radiation Exposure ALARA (top)

The acronym ALARA, which stands for As Low As Reasonably Achievable, means that radiation workers should make every reasonable effort to keep
radiation exposures as far below regulatory dose limits as practical. Adhering to the following practices can help keep radiation doses ALARA.

• Be familiar with the properties of the radioisotope to be used and with any precautions and concerns specific to that radioisotope and material. (See Appendix B for detailed information about the radioisotopes most commonly used at the University).
  
• Unfamiliar radioisotope procedures should be rehearsed before radioactive material is actually used.
  
• Wear protective clothing.
  
• Wear radiation monitor badges when appropriate.
  
• Have all the necessary materials and equipment available and ready at the start of a procedure.
  
• For those radioisotopes with significant external radiation levels, use remote handling tools, such as tongs, to limit direct handling of stock and sample vials.
  
• Survey frequently and extensively. Don't assume that contamination will only be found on the bench top.
  
• Clean up contamination in the work area promptly.
  
• Change gloves and lab coats as they become contaminated.
  
• Work in a hood during procedures using volatile materials such as I-125 or millicurie amounts of S-35 methionine/cysteine.
  
• Cover radioactive waste cans at all times and store waste cans away from areas in which people spend substantial amounts of time. Provide shielding for waste cans with significant external radiation levels.
  
• Do not store contaminated materials, including gels, at any desk area.
  
• Survey yourself and your clothing when radioisotope work is finished and before leaving the lab.