Re: Shoe store fluoro units -- Summary

[John Moulder <jmoulder@post.its.mcw.edu>]

> Something does not add up! 
> Dose rate 0.5 - 5.8 R/s 
> Exposure time 5 - 45 s 
> entrance dose to feet 0.7 - 14 R  now 0.5 x 5 = 2.5 R and 5.8 
> x 45 = 261 R So shouldn't the entrance foot dose be anywhere from 2.5 
> to 261 R (scary though t for you old guys eh?) 

The dose rate data, and the foot dose data are from different sources, 
neither of which has anything like the level of methodological data that 
would now be standard.

But several things are clear:
1)  These were high dose fluoro units that delivered a substantial gonadal 
dose and whole body dose to the customer
2)  There were a lot of them
3)  They were used with little or no control -- there are quotes about 
finding units where the Al filtration had been removed by the store so that 
the image would be brighter
4)  For some of us, this may have been the major source of radiation exposure 
when we were kids

Some new data:

scatter in viewing (customer) direction:  100-150 mR/hr at 10 ft

leakage from front (opposite customer) and sides:  5-50 mR/hr at surface of 
unit

New York City Sanitary code, section 107a, effective march 1, 1948:  "The 
maximum permissible dose per exposure shall not exceed 2 roentgen.. there 
shall not be more than 3 exposures in one day and not more than a total of 12 
exposures in one years... The equipment shall be so constructed that the 
dosage rate in any region which may be occupied by operators and attendants 
does not exceed 12.5 mR/hr" 

John Moulder (jmoulder@its.mcw.edu)
Radiation Biology Group
Medical College of Wisconsin