[ RadSafe ] Update on lead aprons in nuclear medicine

[Ted de Castro]

With respect to the energy at which they are equivalenced - I'd suggest 
around 90 or so kVp DIRECT diagnostic xray beam.

I say this from my own experimental results.

As a consultant doing annual x-ray machine "calibrations" as local 
hospitals I would also check their aprons for defects and every apron 
got checked at least once for equivalence.

At first I did this the traditional way - set up an attenuation curve 
with calibrated lead filters on a test stand - and then measured the 
attenuation through the garment using a standard radiographic unit.  
(which I had already verified for consistent performance!)

Later I found it quicker and just as accurate to calibrate the 
auto-brightness kVp on a fluoro unit with the calibrated lead filters 
and then just run the garments under the fluoro and note the kVp - thus 
I could inspect and verify equivalence at the same time. Considering in 
a given hospital there would only be two or three different 
"thicknesses" to verify - this was certainly sufficient and efficient.

No, this was not a 5 decimal point verification - however, as I recall 
without looking at old reports, the results were pretty close to the 
label - if any were less than the spec on the label I would have brought 
that garment to their attention and I don't recall ever having to do 
that.  Creases, tears, holes and in one case completely missing sections 
- sure - but never and equivalence issue.

On 8/25/2014 3:42 PM, Lemieux, Bryan P wrote:
> Hello,
>
> You also need to look at what energy the lead equivalence is at.  Many of these composite materials are only "lead equivalent" in the energy range for scatter x-rays from diagnostic energy x-ray beams..... Get the manufacturer data on the actual attenuation properties by energy to see what it would be for your gammas.
>
>
> Bryan Lemieux, M.S., CHP
> Radiation Safety Officer
> University of Tennessee Health Science Center
> 3 N Dunlap St. S110 Van Vleet Bldg
> Memphis, TN 38163
> Phone:  901-448-6114
> Fax:      901-448-7774
>
>
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jeremy Nicoll
> Sent: Monday, August 25, 2014 5:33 PM
> To: The International Radiation Protection (Health Physics) Mailing List
> Subject: Re: [ RadSafe ] Update on lead aprons in nuclear medicine
>
> I'm not quite sure what you're working with, how much and how close, for how long etc., but the HVL for Tc-99m gammas is 0.3 mm Pb, so that should let you do some calcs.  If the thicknesses you talk of are Pb equivalences then the apron isn't going to do a lot, compared with the inconvenience of wearing it, and the thyroid shield, and perhaps the Pb glass specs.
> I don't know of any Nuc Med unit where aprons are worn routinely for RP.
>
> Jeremy
>
> Dr Jeremy J Nicoll
> Radiation Safety Advisor
> University of Otago
>
>
> -----Original Message-----
> From: radsafe-bounces at agni.phys.iit.edu [mailto:radsafe-bounces at agni.phys.iit.edu] On Behalf Of Ålund Maria
> Sent: Thursday, 21 August 2014 12:16 a.m.
> To: radsafe at agni.phys.iit.edu
> Subject: [ RadSafe ] Update on lead aprons in nuclear medicine
>
> Hi,
>
> I am wondering if the lead aprons has ben improved for nuclear medicine workers the latest years. I read a question dated from 1997, *Lead aprons in nuclear medicine,* (*http://health.phys.iit.edu/extended_archive/9703/msg00011.html
> <http://health.phys.iit.edu/extended_archive/9703/msg00011.html>) *that stated that lead aprons suitable for x-rays is not necessarily enough shield to be used for gamma rays. Are the composite aprons that weight less equal as good as a conventional lead apron nowadays? And which thickness should then be used? The aprons that are being used at my workplace is made of the composite material and has the thickness of 0.25 and 0.35mm. The radiophysics says that this is enough.
>
> Thanks for your help.
>
>
>
> Maria Ålund
>
> Biomedical scientist, Sweden
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