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Radiation Monitoring and Decontamination of the Working Area

When the preparation of a 99mTc-radiopharmaceutical is complete, the working area in the LAF cabinet must be cleared and cleaned. Watch a professional perform these procedures in the video 1, then learn about the steps in more detail, below.

Clearing the working area

The working area absorbing paper is discarded into the radioactive waste bin
All materials that cannot be reused (such as used syringes, opened vials of 0.9% saline solution and any other used or opened disposable materials) and could be contaminated with radioactivity (because they have been in contact with a radioactive substance) must be discarded in the radioactive waste bin. The absorbing paper that was used in the working area should also be discarded in the radioactive waste bin. Ideally radioactive waste is separated into radioactive sharps and radioactive non-sharps. Non-radioactive waste is discarded in a non-radioactive waste bin, and usually also separated into sharps and non-sharps. See Radioactive Waste Management for further details.

All instruments that will be used again in other preparations (such as tongs, forceps, syringe shields and lead vial shields) must be checked for radioactive contamination using a radiation detector such as a Geiger-Muller counter. If no contamination is detected, these items should be stored in an appropriate place ready for the next preparation. If the instruments are contaminated, they can be stored in a shielded place until the radioactivity has decayed sufficiently, or they can be decontaminated, for example, by soaking them in a bath of decontaminating solution.

The elution vial shield containing the 99mTc eluate (capped) should be removed from the LAF cabinet and placed behind lead shielding.

The working area and the walls of the LAF cabinet are then checked for contamination with radioactivity using a radiation detector such as a Geiger-Muller counter.

Practise clearing the working area

Decontaminating the working area

If any contamination is detected in the working area, the contaminated area should be cleaned with absorbing paper moistened with a cleaning solution.

Cleaning the working area with absorbing paper moistened with a cleaning solution

After cleaning, the paper should be checked for radioactivity and discarded into the radioactive waste if it contains measurable radioactivity.

Checking the radioactivity of the cleaning paper using a GM-Counter

The paper used for cleaning is discarded into the radioactive waste bin.

The cleaned area should then be monitored again to see if the level of radioactivity has decreased or disappeared. If measurable radioactivity is still present, the cleaning procedure should be repeated until the radioactivity has disappeared or, if this does not appear to be feasible, until further cleaning does not reduce the level of radioactive contamination. Watch this process in the video on the right.

Learn how to use the Geiger-Müller monitor

If a high level of contamination remains after this cleaning procedure, the safety officer is contacted to discuss the situation and to decide what measures should be taken (such as covering of the contaminated area with sterile absorbing paper and lead shielding or quarantining the LAF cabinet until the radioactivity is sufficiently decayed).