CHAPTER 19 

 THE SAFE HANDLING OF RADIOACTIVE MATERIALS 



19.1. Introduction. The manipulation of radioactive materials presents 

 two major problems with which a laboratory must be adequately prepared to 

 cope in so far as they affect laboratory design, operative procedures, and 

 personnel. These are, in the broadest terms, the health hazard of radiations 

 to which personnel may be exposed and contamination of the laboratory and 

 its equipment. Contamination represents a relatively uncontrolled source 

 of radiation and in this sense must always be regarded as a potential health 

 hazard in addition to the constant danger it poses for confusing experimental 

 results. It demands, almost without exception when active materials are 

 handled in appreciable quantities, that measures be taken to detect and 

 eliminate it. So far as radiation is concerned, little differentiation can be 

 made in the procedures taken to preclude any possibility of excessive per- 

 sonnel exposure, whether the radiation is from contamination or from care- 

 fully handled quantities of active material. 



Fortunately, in most private institutions using radioactive materials in 

 research and for therapy these problems are less complex than in the isotope 

 processing laboratories of the Atomic Energy Commission because the quanti- 

 ties of active material handled are comparatively small. Laboratory design, 

 equipment, and monitoring procedures for this reason often can be made 

 quite simple. Usually the quantity of material will not exceed 100 milli- 

 curies, and rarely is it as great as a curie. Hot cyclotron targets in most 

 instances are likely to be the most active sources to be dealt with and may 

 at times approach the curie level. Almost without exception, however, when 

 active material is handled in amounts greater than tracer quantities (~ 

 microcuries) suitable protective measures must be instituted. 



In addition to the quantity, the species of isotopes that will be handled 

 in a laboratory affects the extent to which precautions must be taken. 

 Isotopes with half-lives of a few hours or days do not present a problem of 

 permanent contamination but usually represent serious health hazards by 

 virtue of the high energy radiation associated with short half-lives. Mate- 

 rials with long half-lives are always serious contaminants in that they may 

 seriously interfere with subsequent experimental results and may or may not 

 be health hazards too. In particular, there is a group of isotopes which 

 constitute a special health hazard irrespective of the energy or type of their 

 radiation. This includes all isotopes with long half-lives that have a tendency 



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