HEALTH PHYSICS AND RADIATION PROTECTION 107 



Film Badges. Film-badge service is commercially available. The 

 developed film serves as a permanent record of the individual's exposure 

 and may thus be of legal value. The film packet usually contains a sen- 

 sitive and an insensitive film which cover the gamma dosage in the range 

 of 30 to 20,000 mr. The primary disadvantage is the time lag between 

 the exposure and the evaluation of the film. The film badge is also insen- 

 sitive to soft-beta radiation. The value of the film badge is questionable 

 in the small laboratory doing tracer work when adecjuate monitoring is 

 available by other methods and detailed records are kept of instrument 

 readings and amounts of activity. 



SUMMARY AND SUGGESTED WORKING RULES 



It is clear that the careless handling of radioactive materials may create 

 a health hazard and may cause serious interference in experimental work 

 on account of cross-contamination. Adequate control will primarily 

 depend upon the actions and integrity of the individual engaged in the 

 work. In perspective, it seems agreed that the inconveniences caused by 

 necessary health-physics practices are seldom unduly restrictive and, in 

 any event, are far outweighed by the productivity of the radioisotope 

 procedures. 



There can be no substitute for experience. In general, the inexpe- 

 rienced worker will and should take more stringent measures than may be 

 required later on as the actualities become apparent. It is suggested that 

 the initial experience be gained with the group I or II isotopes, which 

 present little or no hazard when used in small amounts (e.g., P^^, P^^^-^v^^). 

 Any activity to be employed for the first time should be used at the lowest 

 levels feasible. This gives a "feel" for the handling procedures and con- 

 tamination control that will be required. 



Persons who are naturally neat and careful are to be preferred for 

 radioisotope work. Individuals should be informed of the known dangers 

 that may be involved and should be adequately supervised and instructed 

 as to local rules. It is advisable that medical examinations be made 

 before employment. However, the actual value of such routine examina- 

 tions for the detection of overexposure is highly questionable. For exam- 

 ple, exposure to about 25 r is required before effects on the blood count 

 are noted. Such exposures in a radioisotope laboratory would be unlikely 

 and occur only as the result of gross negligence. 



If internal exposure is suspected, analysis of urine, feces, nasal smear, or 

 sputum may be helpful depending upon the metabolism of the particular 

 element involved. External measurements over the thyroid may be used 

 to estimate body burdens of radioiodine. 



General requirements for radiation control may be stated as follows: 



