Guidelines for safe work with open radioactive materials

Safety Procedure – Working with Open Radioactive Sources

Understand the nature of the hazard of the radioactive material (radioisotopes) you intend to use and get practical training from the Radiation Safety Officer for proper handling and work. The use of sources is limited only to authorized radiation workers and the type of open source.

  1. Plan your actions ahead to minimize time spent handling of the radioactive material. shorte time, lead to lower radiation dose exposure. 
    Run a “cold” trial experiment to acquire good practice laboratory skills 
  2. Work as far as possible distance from the radiation source.
    Doubling the distance from the radiation source reduces the radiation dose significantly (the inverse square law).
  3. Use an appropriate anti-radiation shield.
    Perspex for beta ()-emitters; lead (in the appropriate thickness) for gamma () emitters. Place the Perspex shielding close to the source and the lead shielding behind it.
  4. Use a personal dosimeter (radiation tag) and protective PPE (Personal protective equipment) as required.
    1. Use personal protective such as: A closed lab coat, latex or nitrile gloves and safety glasses.
    2. Gloves should be replaced often.
  5. Concentrate the work in a defined, clearly marked area. 
    1. Work only on a work surface designated for radioactive work. The surface must be covered with a cloth.
    2. Working with some radioactive compounds (such as S-35  or I-125) must be conducted in a chemical hood. Some of the work processes create reactions that result in volatile radioactive products.
  6. Monitor the work area frequently using aa validated Geiger counter or a liquid scintillation counter (smear test), depending on radiation type and intensity, for early detection of a possible contamination.
  7. Follow the safety rules and instructions. 
    1. All equipment and devices intended for use with a radioactive source must be signposted with a radioactive standard label.
    2. Do not work with radioactive materials when there are open wounds in your hands.
    3. Do not eat, drink, smoke or apply makeup in the laboratory.
    4. Mouth pipetting is prohibited; use a pipette controller with a tip dispenser. 
    5. The lab must have standard washing facilities: Elbow-controlled faucet, elbow-controlled soap dispenser and paper towel dispenser.
  8. Store materials that contain radioactive compounds in designated areas, clearly marking them with your name.
  9.  Do not accumulate radioactive waste, disposing of it as soon as possible, according to the instructions.
    1. Radioactive waste is removed as solid waste only. Liquid waste will be transferred to a collection vessel containing vermiculite, so that no liquid remains in the vessel (all fluids must be saturated in the vermiculite).
    2. Use only containers designated for radioactive waste (shielded if necessary).
    3. At the end of the work, transfer the waste to the yellow radioactive waste barrel. 
  10. Upon finishing your work, examine yourself.   
  11. The worker must check him/herself and the work area, including the lab floor, at the end of the work and when leaving the lab. If a contamination is revealed, report immediately to 08-9342999. What about medical test – Yehuda?

Procedure for performing iodination

Procedure for performing iodination with radioactive I125 in the research laboratories at the Weizmann Institute

  1. The use of I125 in iodination procedures in laboratories, will be performed only in a proper chemical/radioactive fume hood after the approval of the Weizmann safety unit and provided that the amount does not exceed 100 µCi per assay.
  2. About two months before the scheduled date of the iodination procedure, the radiation safety supervisor must be informed, for the purpose of the work to be performed.
    1. The laboratory where the iodination will take place should be part of the permit to deal with radioactive materials and should be equipped with appropriate and calibrated shielding and monitoring devices.
    2. The intended user should contact the head of the air conditioning department in the Construction and Engineering Division in order to check the hoods in the researcher's laboratory using a smoke grenade. After the test, the certificate of the correctness of the hoods should be sent to the radiation safety supervisor.
    3. You must contact the radiation safety officer (Yehuda Moshayev ext. 5515, mobile: 050-9001995) and go over the protocol of the iodination procedure to confirm the suitability of the accompanying equipment involved in performing the iodination procedure in the laboratory.
    4. The iodination procedure will only be performed by employees defined by the institute as an authorized radiation worker, who have passed the required medical examinations and participated in individual radiation training according to the local Israeli law.
    5. Only radiation workers with previous experience who are skilled in working with I125 will be allowed to perform the iodination procedure.
  3. Work in the hood: 
    1. The iodination will be performed on an empty surface, free of equipment in order to avoid air turbulence in the hood.
    2. Free flow of air in the hood must be guaranteed by placing large equipment on raised surfaces at a height of about five cm.
    3. The work surface will be padded with an absorbent diaper impervious to liquids.
    4. During work, the hood window will be open no more than the lower third..3
  4. Required personal protective equipment:
    1.  Protective glasses
    2.  A long-zipped lab coat
    3. Two pairs of nitrile gloves
    4. Closed shoes
  5. Monitoring tags:        
    1. The worker is required to wear chest badge and finger badge.
      A finger badge will be placed under the gloves, with the crystal facing the inside of the palm.
  6. Geiger counter: The laboratory must have a calibrated Geiger counter suitable for detecting gamma radiation emitted from I125
    When conducting the iodination, the Geiger counter will be placed towards the work area, allowing quick access to check for contamination in gloves and surfaces .
  7. At the end of the iodination process, the entire working environment must be monitored, including all those present in the laboratory (shoes, hands and clothing) 
  8. The employee must perform radio-toxicological tests within forty-eight hours after the iodination, as required by law and in coordination with the radiation safety (by whom and were are the results accumulated Yehuda?) officer.

Working with radioactive materials with animals

Permission must be obtained to work with experimental animals and radioactive material
The following precautions should be taken:

  • Use personal protective equipment: gloves, safety glasses, long closed lab coat and closed shoes.
  • Use disposable utensils and syringe with a retractable needle.
  • Avoid stabbing or spilling.
  • Collect carcasses of animals, waste and excretion.
  • Signpost the cages with radioactive labels.
  • Monitor cages and work surface.
  • Clean cages and work surface at the end of the work.
  • It is recommended to use disposable cages.

Environmental monitoring & decontamination

The radiation safety officer performs environmental monitoring during routine inspections at the laboratories.

Environmental monitoring will be performed by the employee during experiments, especially at the end of the work and while disposing the radioactive waste. The monitoring should include Geiger counter and Smear test.

In case of contamination, decontamination must be carried out using a spray device. Repeat spraying several times until the monitoring device shows background radiation. If it cannot be cleaned, mark the device or spill area with a label “radioactive contamination”.

In any case of contamination or suspected contamination immediately report the service center at 08-9342999 and the radiation safety officer at 08-9345155.

Check devices before repair

Laboratory devices that need repair must be monitored and confirmed that they are not contaminated before they are collected from the laboratory. A clean device will bear a label signed by the safety warden.