Methods of Minimizing External Dose

DOE-HDBK-1106-97

Radiological Contamination Control Training

for Laboratory Research

Student's Guide

4.0

Methods of Minimizing External Dose

4.1

Distance

Maintain the greatest distance possible between the worker and the gamma-emitting animal

to make full use of the inverse square law. This law, simply stated, implies that if the

distance from a radioactive source is doubled, the dose is reduced by a factor of four.

4.2

Time

When the distance cannot be minimized, the amount of time spent in the proximity of the

radioactive animal should be kept at a minimum.

4.3

Shielding

When the above is not possible for any reason or when the dose rate is determined to be

very high, lead shielding of the proper thickness should be placed between the worker and

animal. This is a clumsy technique and should only be attempted following consultation

with a health physicist.

4.4

Source Reduction

Following the experiment and/or the death the animal, proper waste disposal proceedings

should be initiated.

5.0

Methods of Minimizing Internal Dose

When handling radioactive animals or applying radionuclides to animals, it is required that the

handler wear gloves that can be thrown away when contaminated. This will prevent the transfer of

radionuclides from hand to mouth and is equally important when handling excreta or animal parts

that may be radioactive.

Procedures for handling of the animal should be implemented to reduce the possibility of animal

bites. This would include such activities as sedation of the animal in some procedures and special

handling techniques for specific animals in other procedures. Both the researcher and the animal

handler should be trained in these procedures.

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