Fwd: Palladium Calibration

[Ccja@aol.com]

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Forwarded message:
From:	MMcGary@HEALTH-FIRST.ORG (Mary Ellen McGary)
Sender:	medphys@LISTS.WAYNE.EDU (Medical Physics Listserver)
Reply-to:	MEDPHYS@LISTS.WAYNE.EDU (Medical Physics Mailing List)
To:	MEDPHYS@LISTS.WAYNE.EDU (Multiple recipients of list MEDPHYS)
Date: 97-10-08 00:31:15 EDT

Dear Colleagues,

A fairly large number of people have been e-mailing me for more
details about the 8% shift in Pd-103 calibration.  This is what we
understand led to the change.  Theragenics had an 8% (increased)
change in the NIST calibration factor for a new Cd-109 source.
The Cd-109 source is used to calibrate a NaI detector, which is
then used to measure the activity of five Pd-103 seeds.  These five
seeds are then used to calibrate their Capintec ion chamber, which
is thereafter used to calibrate the seeds they distribute.  This is
information received over the telephone, so it may not be 100%
accurate.  I urge you to contact Theragenics directly for complete
details.

Here's an interesting follow-up.... I understand from Larry Berkley
that Theragenics made a downward adjustment of about 8%
several years ago, so they have basically returned to their former
calibration.


Mary Ellen Masterson-McGary
Holmes Regional Medical Center
mmcgary@health-first.org