Bone Mineral Densitometer at UIUC

[Paul W. Shafer <shafer@jumprun.ehs.uiuc.edu>]

The Kinesiology Department at UIUC operates a Norland Cameron Digital Bone  
Densiotometer which uses 200 mCi of I-125 as its source, and Hologic QDR-1000 dual  
energy x-ray bone densitometer.  In the Risk Analysis for the QDR-1000, the  
following is described, " The QDR-1000 has a self-contained x-ray source, mounted  
in the table, which provides alternating pulses of 70 and 140 kVp, and a detector  
which is mounted above the table. The average skin entrance dose for the subject is  
less than 1.5 mrem within the scan field and a maximum dose of 3.5 mrem at the edge  
of the scan field.  The total integrated dosage that a subject would receive,  
involving a scan of the spine, a scan of the femur, and a total body scan, would be  
15 mrem.  The operator exposure at one meter from the very tightly collimated beam  
path and scanning table is less than 0.1 mR/h."  Actual measurements of background
radiation with the unit operating ranged from 0.04 to 0.07 mR/h.  No additional  
shielding was needed.


Paul W. Shafer