[Intl_DxMedPhys] Webster 1 Calculation & Protective Lead Thickness.

[Martin, Michael]

Good morning,

NCRP 122 gives background on the Webster method, and Table 3.4 provides corrections for 0.3 mm vs 0.5 mm. It’s getting long in the tooth, but several good references for further digging.

Best,

T. Michael Martin PhD, DABSNM, DABHP, LMP  |  Sr. Health Physicist and Assistant RSO
Environmental Health & Safety | Texas A&M University
4472 TAMU | College Station, TX 77843-4472

ph: 979.458.0365  |   michael.martin at tamu.edu<mailto:michael.martin at tamu.edu>
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TEXAS A&M UNIVERSITY
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From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu> On Behalf Of David Eastman via Intl_dxmedphys_wd_osu_list
Sent: Thursday, January 15, 2026 5:28 PM
To: intl_dxmedphys_wd_osu_list at lists.osu.edu
Subject: Re: [Intl_DxMedPhys] Webster 1 Calculation & Protective Lead Thickness.

To Whom It May Concern, I'm wondering if anyone would be able to share the lead, or lead equivalent, protective apron thickness as it relates to the Webster 1 (or EDE2) calculation, when one badge is worn outside the lead and at the collar.  
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To Whom It May Concern, I'm wondering if anyone would be able to share the lead, or lead equivalent, protective apron thickness as it relates to the Webster 1 (or EDE2) calculation, when one badge is worn outside the lead and at the collar. 
To Whom It May Concern,

I'm wondering if anyone would be able to share the lead, or lead equivalent, protective apron thickness as it relates to the Webster 1 (or EDE2) calculation, when one badge is worn outside the lead and at the collar.  Basically, I'm wondering what thickness of lead was used when creating the Webster 1 correction (i.e. 0.25 mm, 0.3 mm, 0.5 mm)?

I'm asking because when the Webster 1 (EDE2) correction has been applied to one's measured whole body dose (or DDE), I have thought that when a 0.5 mm lead equivalent apron was worn, a conservative dose correction was provided.

However, I've recently learned that some staff have been wearing protective lead closer to a 0.3 mm lead equivalence, and they have still had the Webster 1 correction applied to their dose report.  So, I'm wondering if the Webster 1 correction is now just more accurate, rather than conservative?  Or, has the Webster 1 correction caused the reported dosimetry results to be falsely low due to one wearing a 0.3 mm lead equivalent apron, rather than a 0.5 mm lead equivalent apron?

Thank you for your time and assistance regarding this inquiry.  Please know it is greatly appreciated.

Have a great rest of your day!


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David J. Eastman, M.E.H.S.

Medical Health Physicist &

Radiation Safety Officer



O: (218) 786-1026

C: (218) 341-0971

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