Hologic QDR X-ray Bone Densitometer RAD Protection

[pjconnol@chaph.usc.edu (Philip Jon Connolly)]

November 24, 1993 Dr. James Sims of UNT Fort Worth writes:

> We have a physician that plans to acquire a model QDR-1500 Hologic
> QDR Bone Densitometer.  I have reviewed the sales literature that
> suggests that additional lead shielding of walls is not needed and
> that the operator console need not be shielded.  Does anyone have
> experience with these units and willing to share the protection
> measures taken?  I'm particularly interested about experiences in
> the Texas regulatory environment.

The University of Southern California has recently acquired this same bone
densitometer for use in the Excercise Sciences department.  The Radiation
Protection Department surveyed the instrument in operation with a spine phantom
in place and the scatter results were 0.9 to 1.4 mR/hr at one foot from
phantom and 0.2 mR/hr at the head of the table (approx. 3 feet) 
and < 0.1 mR/hr at the operators station (approx. 5 feet).  There was no 
detectable x ray in the adjacent office, a distance of about 5 feet with an
adjoining wall.  Tube head leakage was also measured and found to be zero
at 1 meter.  Measurements were made with a Keithley Model 36150 Integrating
Radiation Survey Meter.  As the above measurements indicate, no shielding
was required.


Maymie Chenoweth
Phil Connolly
Health Physicists				phone: (213) 740-7310
University of Southern California		email: pjconnol@usc.edu
University Park Campus				  fax: (213) 740-7305	
Los Angeles, CA 90089
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