Re:Shoe fluoroscopy

[jrcamero@facstaff.wisc.edu (John Cameron)]

Most states had banned shoe fluoroscopes by 1958. I obtained one of these
units at that time in good condition  It had an output of about 100 R/min
at the sole of the shoe A timer limited the exposure to 5 s for each push
of the button. It had 3 viewing ports. A sketch of the unit appears in my
old book Medical Physics (Wiley 1978 - out of print). I used the unit for
class demonstrations for many years. Its leakage radiation was easily
detected 30 meters away!  Typical exposures to the students in the front
row were still in the microR range. 
        In 1928 a high school graduate in Wisconsin got a job in a factory
in Milwaukee that manufactured shoe fluoroscopes. His job was to test them
by looking at his feet in them! His daughter is/was a secretary in the Dept
of Radiology at UW. She told me that over the years his feet and lower legs
were progressively removed due to tissue damage. He died at age 70 but not
from cancer. 
        Contrary to common belief it takes a lot of radiation to cause
cancer in most people. The recent centennial book from Canada - A NEW TYPE
OF RAYS describes the case of the radioactive ring made from made from gold
originally used for radon seeds. The dose from Pb 210 (20 year half-life)
over a period of 30 years gave the wearer's finger about 4000 Gy (Yes,
400,000 rads) before any signs of skin cancer appeared! S ome radium
luminizers had skeletal doses from radium of 50,000 rads (ONE MILLION
REMS!) without having cancer. In fact 2/3 of them did not have radiation
induced cancer. See Robley Evans - Radium in Man Nov 1974 HPJ pp 497-510.
The new book RADIUM IN HUMANS by R.E. Rowland published by Argonne Nat. Lab
1995 states that no luminizers who started work after 1925 - the year they
were forbidden to touch the brush to their tongue or mouth - ever developed
a radiation induced bone cancer! In addition, despite the huge doses to the
skeleton the study group of about 6500 had no increase in leukemia - so
much for the tissue weighting factor of 0.12 for bone based on leukemia
deaths in A-bomb survivors! The total bone  cancer deaths were about 1.3%.
About the same as the additional cancer deaths of the bomb survivors. Those
who did not die of cancer lived longer than age matched controls in both
groups. 
        There is a need for radiation museums that uses real radiation. You
don't need much to demonstrate its properties. Spintherascopes which
permitted kids to see radium alpha particles strike a fluroescent screen
were popular 50 years ago. Only a few hundred Bq would do the trick!
         I hope these comments are educatonal. John

>Some radsafers might remember the fluoroscopy machines which appeared for a
>while in the children's department of shoe stores, where you could peer at
>your wriggling metatarsals etc as often as you liked.  I guess those
>machines ended up at the tip rather than the museum. Does anyone have a
>health physics reference to them?
>Jocelyn Towson
John R. Cameron 2678 SW 14th Drive, Gainesville, FL 32608-2050 
phone: 904/371-9865; fax 904/371-9866  e-mail: jrcamero@facstaff.wisc.edu