Re: HVL of Lu-177

[Brian_Gaulke@hc-sc.gc.ca]

Brian Gaulke
02/16/99 05:14 PM

I did a sensitivity analysis using MicroShield v4.0.  I used 10 mm Pb as my
reference point and calculated 20 points from 1 mm to 20 mm inclusive..

The results can be fit reasonably well by a HVL of 0.846 mm Pb from 1
through 6 mm (r^2 = 0.997), and a HVL of 1.816 mm Pb from 10 through 20 mm
(r^2 = 0.9998).  The errors in calculated exposure rates are less than 10%
for the smaller thicknesses, and less than 4% for the greater thicknesses.
The maximum error in the intervening range (between 6 and 10 mm Pb), using
whichever equation gives the best result, is about 30% at 7 mm Pb.

This indicates that Les was basically correct (there isn't a single
constant HVL), but the results are simpler than you might expect given the
complexity of the spectrum.

Brian R. Gaulke, CHP
Head, Dosimetry Section
Radiation Protection Bureau
Health Canada
(613) 941-0143
Brian_Gaulke@hc-sc.gc.ca





Wade.A.Sewell @ dupontpharma.com on 99-02-16 10:33:31 AM

Please respond to radsafe@romulus.ehs.uiuc.edu

To:   radsafe @ romulus.ehs.uiuc.edu
cc:    (bcc: Brian Gaulke)
Subject:  HVL of Lu-177




Dear Radsafer,
I need to know the Half value layer (in lead) of Lu-177.  I used the
equation
for the mean attenuation coefficient on page 165 of the Rad health Handbook
(Revised edition) and determined the thickness of lead for 95% attenuation
to be
2.74 mm.  I am skeptical of this approach and/or my use of it.
Please send all correspondence to me.
Many Thanks!
Wade Sewell
wade.a.sewell@dupontpharma.com
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