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15.1 Radionuclide Fume Hoods

The Fred Hutchinson Cancer Research Center maintains specially-equipped radionuclide fume hoods. These fume hoods are lined with stainless steel to facilitate clean-up and when using volitle isotopes, are exhausted through carbon and high-efficiency filters to protect the environment. These fumehoods are certified annually in accordance with manufacturer's specifications. The Fred Hutch radionuclide fume hoods are found in the following locations:

 

 

 

A3-201

B2-196

DE-750

BE-221

C1-111

A3-111

D2-335

D3-322

 

M5-A424

M5-C118

 

EH&S recommends the use of one of these hoods for the following procedures:

Iodinations using more than 1 mCi of 125I or 131I

Labeling using more than 10 mCi of 35S

Labeling using more than 50 mCi of 32P or 3H

15.2 Joint Use Hot Lab

The Joint Use Hot Lab (DE-750) must be used for iodination greater than 5 mCi. It may be used for any iodinations or for other higher risk experiments.

When using DE-750, the following procedures must be followed to protect yourself and others from exposure to radioactive contamination on surfaces and from excessive dose rates from material in storage:

  1. Be trained by the RSO or ARSO in person at DE-750.
  2. Reserve the Hot Lab for the date and time using the SharePoint Hot Lab Calendar.
  3. All radioactive material left for decay or future use in the hot lab must be labeled with the isotope, activity, date, and user's name.

Perform and record an instrument survey and/or a wipe survey (background is too high sometimes in some areas) after you finish your work and record the survey in the Hot Lab notebook. All Hot Lab users are required to undergo a one-on-one training with the Radiation Safety Office staff.

15.3 Volatile Isotope Controls

15.3.1 Iodine Use

Iodinations using 131I or 125I are performed in the Joint Use Hot Lab (DE-750) large hood. To reduce external exposures, use the lead cave for shielding while performing iodination and use remote handling tools (forceps and tongs) to manipulate vials and reaction vessels. To reduce internal exposures caused by inhaling volatile iodine, use charcoal traps while venting the shipping vial and making pH adjustments using a closed transfer system.

15.3.2 Contamination Control for 35S

To reduce the potential airborne hazard and contamination of 35S, EH&S recommends the following:

  1. Minimize contamination by using the sulfur-labeled amino acids stabilized with tricine. Tricine is a biological buffer that is non-toxic to cells and does not inhibit in vitro translation. Tricine-stabilized methionine reduces the rate of radiolytic decay into volatile by-products.
  2. Always open stock vials in the chemical fume hood. In some preliminary experiments done by EH&S, the volatile product was released during thawing before the vial had been opened.
  3. Perform all 35S-labeled experiments in a designated incubator.
  4. Change the incubator water biweekly.
  5. Charcoal and/or charcoal filters can be used to absorb volatile 35S in incubators.
  6. Charcoal traps can be used while initially opening vials.

15.4 Use of Radioactive Material in Animals

These procedures (and the more detailed AHR SOPs) ensure that proper health and safety precautions are taken when using radioactive material in animals at the Hutch. These procedures apply to all research involving administration of radioactive material to experimental animals, to include 3H,14C,32P,35S,125I,131I, and other radionuclides authorized under the Fred Hutch radioactive material license.

15.4.1 Prior Approval and Notification

Each Principal investigator (PI) who intends to use radioactive material in animal research must have an RMUA for animal use approved by the RSC. RMUA Attachment 1 must be completed.

15.4.2 Procedures

  1. 125I and 131I iodinations are performed in the Joint Use Hot Lab, Room DE-750. Other radionuclide solutions may be prepared in the researcher's lab or DE-750. Animals are to be dosed in the AHR facility only.
  2. Due to the gamma radiation hazard and potential volatility of radioiodine, animals will only be administered 125I or 131I in the Hot Mouse Suite, Rm BE-221 in the AHR facility.
  3. Researchers and AHR staff involved in the care of animals administered radioiodine may require thyroid bioassays in accordance with Section 11.4, Thyroid Bioassays.

15.4.3 Radioactive Animal Housing

  1. Animals administered 3H,14C, or other beta/gamma emitting radionuclides in quantities that do not present an external or volatile radiation hazard (see Table 15.4.3.1) may be housed in rooms with non-radioactive animals with RSO permission. A radioactive animal must not be placed in the same cage with a non-radioactive animal.
  2. Cages containing radioactive animals will be labeled with a Caution--Radioactive Material label listing the radionuclide, quantity, and date administered.
  3. Radioactive material labels will remain on the cage for ten effective half-lives of the radionuclide (see Table 15.4.3.2) or until the animal is euthanized, whichever occurs first. Any exceptions to this must be approved by the RSO.

Table 15.4.3.1: Radioactive Animal Guidelines:Limits for Housing Radioactive Animals in a Room with Non-radioactive Animals

Radionuclide

Microcuries per Cage

Carbon-14

1,000

Chromium-51

100

Hydrogen-3 (Tritium)

1,000

Iodine-125 or 131

10

Phosphorus-32

100

Yttrium-90

100

All other radionuclides

Contact EH&S for information

Table 15.4.3.2: Radioactive Precautions Required (10 Effective Half-lives)

Radionuclide

Radioactive Precautions Required

Carbon-14

4 months

Chromium-51

9 months

Hydrogen-3 (Tritium)

4 months

Iodine-131

2 months

Phosphorus-32

3 months

Yttrium-90

20 days

All other radionuclides

Contact EH&S for information

15.4.4 Radioactive Material Quantities Requiring Posting of Room

When the total quantity of radioactive material in a room exceeds amounts listed in Table 15.4.4.1, the entrance to the room must be posted with a Caution - Radioactive Material sign.

Table 15.4.4.1: Radioactive Material Quantities Requiring Posting of Room

Radionuclide

Total Microcuries in Room

Carbon-14

10,000

Chromium-51

10,000

Hydrogen-3 (Tritium)

10,000

Iodine-131

10

Phosphorus-32

100

Yttrium-90

100

All other radionuclides

Contact EH&S for posting requirements

Reference: WAC 246-221-120, Washington State Department of Health, Division of Radiation Protection

Where there is a combination of radionuclides in a room, the limit for the combination is derived as follows: Determine, for each nuclide in the combination, the ratio between the quantity present in the combination and the limit otherwise established for the specific nuclide when not in combination (Table 15.4.4.1). The sum of such ratios for all the radionuclides in the combination may not exceed 1 (i.e., unity).

Example: If a particular room contains 2000 μCi of 14C and 50 μCi of 90Y, the maximum amount of 3H in the room must stay below 3,000 μCi for the room to remain unposted. The limit was determined as follows:

2000 μCi 14C/10,000 μCi + 50 μCi 90Y/100 μCi + 3,000 μCi 3H/10,000 μCi = 1

Disposable cage bottoms or disposable tray liners may be used to collect the urine and feces of animals who are administered radioactive material until radioactive precautions are no longer required and the radioactive material label is removed from the cage. Standard radiation safety precautions are taken to prevent the spread of radioactive contamination when handling radioactive animals. These include, at a minimum, the wearing of protective clothing (lab coat or gown), and disposable gloves.

After administering the radioactive material, the researcher places all radioactive sharps in a sharps container labeled with a radioactive waste label, and all other radioactive waste (including absorbent paper, disposable clothing, gloves, etc.) in a properly labeled radioactive waste container. The researcher surveys the treatment area with an appropriate radiation detection survey meter and decontaminates it if contamination levels exceed institutional action limits (see Section 12.2.10). Use of 3H requires a wipe test and liquid scintillation counting to detect contamination.

EH&S may monitor animals and cages following the administration of radioactive material. Cages and other potentially contaminated equipment will be decontaminated as necessary prior to release for non-radioactive use.

15.4.5 Biological Radioactive Waste (Animal Carcasses)

Animal carcasses containing greater than 0.05 μCi of 3H or 14C per gram of tissue averaged over the weight of the entire animal, or any amount of other radionuclides, must be disposed of as radioactive waste. For details, see Chapter VI, Section 7.4, Biological Radioactive Waste (Animal Carcasses).

If the radioactive material is concentrated in only certain organs, these organs can be removed for disposal as radioactive waste and the carcass can be treated as biohazardous waste which lowers the cost of disposal. (see Chapter VI, Section 8, Biohazardous Waste)

15.5 Special Controls for High Activity Laboratories

15.5.1 Contaminated Work Areas

Laboratories with high use of radioactive isotopes (use of > 100 mCi per year of a combination of all isotopes) may set up designated areas (contamination areas) in the laboratories for routine use of radioactive materials and use a 100 times higher limit for contamination in that area. To set up a contaminated area:

  1. Horizontal surfaces where work will be performed must be covered with absorbent bench top pads or other backed absorbent liners.
  2. The contaminated area must have clearly marked boundaries, using yellow and magenta/purple tape stating Radioactive Material.
  3. A sign must be placed near the contaminated area stating Caution--Radioactive Contaminated Area.
  4. The contaminated area should be located away from high traffic areas.
  5. Equipment used in the contaminated area should be dedicated to radioactive use and not used for non-radioactive work. If removed from that area, external contamination levels must be less than 500 cpm.
  6. The contaminated area should be surveyed following all radioactive use and decontaminated if contamination levels exceed 50,000 cpm. Documenting this survey is not required.
  7. The surrounding area should be surveyed following all radioactive use in the contaminated area, and decontaminated if levels exceed 200 cpm. Documenting this survey is not required.
  8. The contaminated area must have a documented monthly survey and be decontaminated to less than 50,000 cpm.
  9. The areas surrounding the contaminated area must be surveyed monthly and decontaminated to less than 200 cpm. This survey must also be documented.
  10. Each worker who finishes working in the contaminated area must monitor his or her hands, face, shoes, and lab coat prior to leaving the lab with an appropriate meter at an appropriate rate.
  11. Only staff who have had the Fred Hutch radiation safety training and are wearing appropriate dosimetry can work in contaminated areas.
  12. Anyone working in the contaminated area must wear at least his or her gloves, lab coat, and safety glasses.
  13. All lab staff must be trained regarding the requirements and hazards of the contaminated area.
  14. The contaminated area must remain clear of clutter and not be used as a storage area for miscellaneous equipment.

15.5.2 Internally Contaminated Equipment

In high-use laboratories, certain equipment such as centrifuges may routinely become internally contaminated. It is not worth the time, expense, waste, and radiation dose to continually decontaminate these items. These items must be controlled by:

  1. Properly labeling the equipment with a readable sticker with the words Caution - Radioactive Material and the radiation symbol;
  2. Having the equipment sit on an absorbent pad whenever practical and be located away from high-traffic areas;
  3. Posting a sign near the equipment that clearly identifies that this equipment may be internally contaminated and anyone handling it should wear gloves and monitor his or her hands afterward;
  4. Not using the equipment for non-radioactive work;
  5. Surveying the equipment after each use or at least daily when in use. If direct scans or wipes of the equipment indicate contamination in excess of 50,000 cpm, the instrument must be decontaminated to less than 50,000 cpm (documenting this survey is not required);
  6. Surveying of areas around the equipment and other radioactive work locations after each use, or at least daily, with consideration given to the potential spread of contamination from the contaminated equipment;
  7. Surveying the equipment monthly and documenting decontamination to less than 50,000 cpm; and
  8. Contacting EHS prior to disposal of the equipment.

Note: All staff in these labs must be trained regarding the requirements and hazards of the contaminated equipment.