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Special Handling Procedures

Special Handling Procedures

Reviewed 5/31/16

Special Procedures for Handling Iodine-125 and Iodine-131.

      Due to the volatile nature of iodine in its elemental form, its low solubility in aqueous solutions, and the ease with which it is oxidized to the elemental form, special care must be taken when opening containers of radioiodine.  Aqueous solutions of sodium iodide may contain 125I in the gaseous phase above the liquid.  Opening the container will release radioactive 125I.  In order to prevent inhalation of radioiodine and to reduce the amount of radioiodine released into the environment, we are asking each user to follow the protocol outlined below:

1. If at all possible, purchase radioiodine only in containers equipped with a rubber diaphragm or septum.  Use of a syringe and needle to add or transfer material would approximate a sealed system and reduce the possibility of radioiodine release.  Once the radioiodine is bound, for instance, to a protein, the material can be handled in an open system.

2. If venting of the container received from the vendor is necessary, such venting must be done through an activated charcoal trap.  The traps are available through the Radiation Safety Office and come equipped with a needle for insertion through the septum.

3. If your particular use requires radioiodine obtainable only in screw-cap containers without septa, the volatile 125I must be vented in a closed system before opening in a fume hood.  We require that the venting be done in the special glove box located in the radioactive the radiation safety office, UH 636.

     Alternatively, by arrangement with the Radiation Safety Office, the office will vent shipments as they arrive from the vendor.  Please make these arrangements at the time of ordering.

Note:  The handling of materials containing radioiodine should always be done in a fume hood having an acceptable face velocity, e.g. >100 feet per minute.  Also, keeping NaI solutions basic will help to minimize the production of I2.

4. All containers holding radioactive iodine compounds should be opened in a hood of proper design which has been checked and approved by the Radiation Safety Office and has a face velocity of 100 feet per minute, or greater.

5. When performing iodinations, two pairs of gloves should be worn as iodine has been shown to penetrate one thickness of plastic gloves.

6. Contaminated items can be decontaminated by using a solution of 0.1 M NaI, 0.1 M NaOH, 0.1 M Na2S2O3.  Overnight soaking in the solution followed by rinsing in water will remove the major portion of I2

Some Precautions For Sulfur-35 Compounds.

      Solutions of S-35 labeled amino acids and S-35 labeled ATP can release a volatile radioactive component when opened.  Although the amount of S-35 released from a stock vial is small, contamination can occur, and it is prudent to observe a few precautions.  The following are recommended:

a) Open stock vials, etc. in a properly functioning fume hood.

b) If possible, do assays in larger volumes, e.g. >14 ml/mCi or in a sealed container. 

c) Tricine (50 mM) can be added as a stabilizer in incubation media if it will not be toxic to the biological agents in culture.

NOTE:  Charcoal is not a good trapping material for S-35 as the absorption is passive and the S-35 will be released from the charcoal over time.

Permissible Levels of Radiation Dose in Unrestricted Areas

     No authorized user shall possess, use or transfer sources of radiation in such a manner as to create in any unrestricted area from such sources of radiation in his or her possessions:

a) Radiation levels which, if an individual were continuously present in the area could result in his or her receiving a dose in excess of 2 millirems in any one hour; or,

b) Radiation levels which, if an individual were continuously present in the area could result in his or her receiving a dose in excess of 100 millirems in any seven (7) consecutive days.

NOTE:  The above radiation levels apply to the operation of any source of ionizing radiation, e.g., x-ray machines, electron microscopes, etc.

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