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RADIATION SAFETY MANUAL
Section 5: Use of Radioisotopes in the Laboratory

INDEX
5.0 General
5.1 Radioisotope Laboratories
5.2 Low Level Laboratories
5.3 Medium Level Laboratories
5.4 Storage of Radioactive Materials
5.5 Safe Use of Radioisotopes

5.0 GENERAL
All users of radioisotopes must have areas designed specifically for the handling, storage and disposal of radioisotopes. A number of basic rules apply to the use of radioisotopes and to storage and disposal of radioactive waste. Please refer also to Australian Standard 2243.4 (1998).

All laboratories must comply with the general University Laboratory Safety Policy and follow the Guidelines for Safe Laboratory Practice.

There will be annual inspections of all Laboratory areas.

5.1 RADIOISOTOPE LABORATORIES
The Australian Standard classifies laboratories into Low, Medium and High level laboratories. Classification of radiotoxicities in Schedule 1 of the Regulations (2003) (see Appendix I) can be incorporated in a grading system that relates the standards of finish and facilities in a laboratory to the amounts of unsealed radioactive materials that can be used safely in it. Table 5.1 shows laboratory gradings for normal, wet chemical operations. Because of the potential for radioactive contamination is largely determined by the nature of the work (eg storage presents a reduced risk, whereas dusty operations increase the inhalation hazard), the factors shown in Table 5.2 can be applied to modify the grading according to the operations performed in the laboratory.

Labelled organic material of special biological importance may be metabolised differently to the elemental form, and hence may present a greater hazard than normal. For example, 3H-labelled or 14C-labelled thymidine is not metabolised but is retained intact by the body. In such cases, an additional grading factor of 0.1 should be applied.

TABLE 5.1 Grading of Radioisotope Laboratories

Radiotoxicity Class I
Low level activity laboratory - <0.2 MBq
Medium level activity laboratory - 0.2 MBq to 20 MBq
High level activity laboratory - >20 MBq

Radiotoxicity Class II
Low level activity laboratory - <20MBq
Medium level activity laboratory - 20 MBq to 2 GBq
High level activity laboratory - >2 GBq

Radiotoxicity Class III
Low level activity laboratory - <2 GBq
Medium level activity laboratory - 2 GBq to 0.2TBq
High level activity laboratory - >0.2 TBq to 20 TBq

Radiotoxicity Class IV
Low level activity laboratory - <0.2 TBq
Medium level activity laboratory - 0.2 TBq to 20 TBq
High level activity laboratory - >20 TBq

TABLE 5.2 Grading Factors

 Procedure Factor  Factor
Simple storage
Very simple wet operations (eg preparation of aliquots of stock solutions)
Normal chemical operations (eg analysis of simple chemical preparation)
Complex wet operations (eg multiple operations, or operations with complex glass apparatus)
Simple dry operations (eg manipulations of powders) and work with volatile radioactive compounds
Complex dry operations (eg where powders are likely to become airborne) and work with radioactive gases 		  x 100
x 10

x 1

x 0.1

x 0.01


x 0.001

We have no high level labs in the University and most would be low level with a few medium level. The "radiation rooms" where stock solutions are prepared and iodinations performed would be classified as medium level.

5.2 LOW LEVEL LABORATORIES
Generally this is where amounts of radioisotope diluted below the prescribed amount (Schedule 1 Appendix I). However it is paramount that there be signs indicating what part of the laboratory is used for these functions and only one designated and labelled sink be used for disposal.

5.3 MEDIUM LEVEL LABORATORIES
The ideal medium level radioscope laboratory should:

  1. Have restricted access and minimum traffic
  2. Display radiation warning signs
  3. Be equipmed with benches with surfaces which lend themselves to decontaminisation, eg stainless steel
  4. Have an easily decontaminated floor, preferabl;y continuous vinyl (with welded seams) extending about 10cm up the walls.
  5. Shall be equipped with a radiation contamination monitor appropriate for the isotopes and energies used.
  6. Have storage areas for bulk radioisotopes and radioactive waste, shielded if necessary Normally unsealed isotopes will be stored in a refrigerator/freezer with a lock, appropriate signage and a list attached of the contents.
  7. Have a designated sink where low activity radioactive material may be disposed of exclusively.
  8. Have a log of radioactive materials used and disposed of.

    If the area is to be used as a "hot lab" for bulk quantities of radioactive material or procedures such as protein iodination, the following is also required:
  9. A fume cupboard with appropriate shielding for handling high specific activity materials
  10. The whole area must be able to be securely locked with entry to only authorised persons.
  11. Basic decontamination equipment must be radily available.
  12. a log is to be kept of all bulk supplies of radioactive materials received in the "hot lab" along with information as to eventual disposition.
  13. The licensee has overall responsibility for the maintenance of documentation and logs. This will be checked periodically by the school/building Radiation Safety Officer.

5.4 STORAGE OF RADIOACTIVE MATERIALS

 5.4.1 As mentioned above, all stock solutions of radioisotopes must be stored in a locked refrigerator/freezer in the Radiation Room or in a designated and well labelled refrigerator in the laboratory adjacent to the Radiation Work Area. Any high activity working solutions must also be stored there.
 5.4.2 All items thus stored must be marked with the users name and a description of the contents, ie name of isotopes, amount of activity, date.
 5.4.3 This information must also be entered in a register
 5.4.4 Any items not properly stored and marked should be disposed of.
 5.4.5 Any material that has expired, or is no longer in use must be disposed of appropriately by the user.

5.5 SAFE USE OF RADIOISOTOPES

 5.5.1

All radioactive material must be considered potentially highly dangerous, and be handled accordingly. As a minimum, the precautions used in sterile techniques for handling pathogenic material should apply at all times.

PLEASE NOTE: PIPETTING BY MOUTH IS NOT PERMITTED

Any person using radioactive material for the first time must consult the Radiation Officer for the area, and satisfy the following criteria:

  • that they understand the procedures being used
  • that they understand, and have in place, procedures for monitoring the laboratory and personnel, procedures for separation and disposal of waste and in the event of a spill or other emergency, know what steps to take.
 5.5.2

For work in low level laboratories, a normal laboratory coat or overall is sufficient. For work in medium level laboratories, the laboratory coat shall have elasticized sleeve cuffs and a crossover front with high neck fastened with velcro strips. Pockets are not recommended.
 5.5.3 Care must be taken to avoid cuts or puncture wounds. Cracked or chipped vessels are not to be used. Any small existing wound should be covered with waterproof dressing during procedures using radioactive materials.
 5.5.4

If there is a risk of splashing during an experiment, eye protection must be worn. Disposable gloves should be worn for all procedures involving radioactive concentrations greater than 1kBq/ml, or total activity greater than 100 kBq. Gloves should be checked with a radiation monitor before disposal. If they exhibit no detectable contamination, then there is no need to treat the gloves as radioactive waste and they can be placed in the normal laboratory bin. If, however, there is contamination 2X background or more, then they must be treated as solid radioactive waste and disposed of as indicated in section 4.8 below.

Please note: It is important not to handle non-contaminated objects with contaminated gloves, particularly if they are not part of the procedure, i.e. door handles, taps, any multiple user item. A radioactive worker must be conscious of this when planning the procedure and if necessary be prepared to use a number of pairs of gloves.
 5.5.5

All work with unsealed liquid sources shall be carried out in a double container or over large trays (eg stainless steel or plastics) lined with absorbent paper to restrict the spread of any spilt liquid.
 5.5.6 Hands should be washed and hands and clothing checked with the radiation monitoring equipment at the completion of procedures.
 5.5.7 A radiation monitor, with a probe appropriate for optimal detection of the energy or particles being emitted by the isotope in use, should be nearby and switched on to "audio" during all manipulations. If there is doubt concerning the appropriate monitor, then the Radiation Officer should be consulted.
 5.5.8

All operations or manipulations with the isotopes as delivered should be carried out in "Radiation Room" which should be clearly designated with appropriate warning signs. If it is absolutely essential that some procedures are carried out in ordinary laboratories then initial dilutions of isotope must be carried out in the Radiation Room and the diluted isotope carried back to the laboratory for subsequent work.

(a) Radioisotopes, clearly labelled with the name of the owner, should be stored in the freezer/refrigerator in the Radiation room. Any high activity diluted solutions should also be stored here.
(b) All reagents, tools and, where possible, apparatus used in the ‘active’ area shall be clearly labelled (eg with paint), and normally remain in the ‘active’ areas. Where any item needs to be taken out of the ‘active’ area, it shall be monitored, decontaminated if necessary and labelled. The label shall identify the laboratory, date and show a signature and the name of the person certifying that the item is free from contamination.
(c) All radioactive preparations shall be clearly marked with the radiation symbol and dettails of the chemical compound, radionuclide, activity, date and name of responsible user.
(d) It is the user's responsibility to ensure that all material is disposed of once it has expired or it is no longer required. When working with a particular element or compound, the total toxicity must be taken into account in its use. The total toxicity may be more than is indicated by the radioactive isotope itself. For example, the compound may be a heavy metal, or carcinogen or a metabolic poison. These features may dictate the specific manner in which a substance is to be handled, in addition to the normal radiation safety requirements. It is the responsibility of the person working with the materials, as well as the Chief Investigator/Team Leader, to ensure that they are aware of all safety ramifications of the substance(s) being used.
 5.5.9

Designation of Work Area
It is essential that any area in the laboratory where work with radioisotopes is being performed, be clearly marked and every precaution taken to contain any accidents or spills. At the very least, this area should be marked with radioactive warning tape and lined with a disposable bench covering such as Bench-Kote. In addition, staff who regularly work with radioisotopes should have access to, or have constructed, a plastic or stainless steel tray to place on the bench when working with radioisotopes. The tray should be of size to conveniently contain all required equipment and a "lip" sufficient to prevent the spread of any potential spill.
 5.5.10 Shielding
Ideally any work requiring shielding should not be conducted in an open laboratory. However, many beta emitters (14C, 32P, 3H) and weak Gamma emitters (59Fe 5I (bound) 51Cr) can be safely manipulated behind a work station constructed from 1.0-1.2cm thick perspex. These can be purchased from a number of suppliers, (eg Amersham, ICN). In addition, for work with concentrated solutions and strong gamma emitters, which should only be performed in a Radiation Room, lead shielding or lead brick walls may be necessary to protect the worker from unnecessary exposure. Details of such shielding should e available from your Radiation Officer.
 5.5.11 Radioactive iodine and any other volatile or sublimating isotope or isotope dissolved in a volatile dilutent must be processed in the Fume Hood in the Radiation Room.
 5.5.12 After completion of any experimental procedure all waste should be removed as specified below. All contaminated equipment or utensils must be removed and washed and decontaminated or disposed of appropriately.