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This has Pb-212, but I haven't had time to check for you if it includes the daughter emissions. It should say in the text what the modeling included. Sincerely, Erin Niven, PhD, CHP, RRPT, MCCPM Sent from Yahoo Mail. Get the app On Thursday,</div>
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</head><body><div class="ydp533cf2e5yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div><div dir="ltr" data-setdir="false">This has Pb-212, but I haven't had time to check for you if it includes the daughter emissions. It should say in the text what the modeling included.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Sincerely, </div><div dir="ltr" data-setdir="false">Erin Niven, PhD, CHP, RRPT, MCCPM</div><div><br></div><div class="ydp533cf2e5signature"><div><br></div><div><br></div><div>Sent from Yahoo Mail. <a href="https://urldefense.com/v3/__https://yho.com/148vdq__;!!KGKeukY!ywQ-7Cg7uiRjR9Z3OKaAtWn0Hguf78a14J0QQD9QkwuC1JtQh76nfOiQs3uIg5_KpCOgIgASAs6HsgQC15BtYefzqW2zea3hFY40NjkV$" rel="nofollow" target="_blank">Get the app</a></div></div></div>
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On Thursday, April 16, 2026 at 05:33:45 p.m. NDT, Gretchen Raterman Bell via Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list@lists.osu.edu> wrote:
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UPDATE: I made a rookie error. Dr. Reagan Dugan pointed out that the Smith/Stabin table only provides HVL data for that isotope and not the daughter products. Gretchen R. Bell, M. S. , DABR Diagnostic Imaging Physicist Ochsner Medical Center (504)842-8506</div>
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<div dir="ltr"><div>UPDATE: I made a rookie error. Dr. Reagan Dugan pointed out that the Smith/Stabin table only provides HVL data for that isotope and not the daughter products.</div><div><div dir="ltr" class="ydp8b565598yiv8277948584gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><p style="text-align:left;"><font face="tahoma, sans-serif"><span style="font-size:small;">Gretchen R. Bell, M.S., DABR</span><br><font size="2">Diagnostic Imaging Physicist</font><br><font size="2">Ochsner Medical Center</font><br><font size="2">(504)842-8506</font></font></p>
<p style="text-align:left;"><span style="font-size:10pt;font-family:Candara, sans-serif;"></span></p></div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="ydp8b565598yiv8277948584gmail_quote ydp8b565598yiv8277948584gmail_quote_container"><div dir="ltr" class="ydp8b565598yiv8277948584gmail_attr">On Thu, Apr 16, 2026 at 2:59 PM Gretchen Raterman Bell <<a href="mailto:gretchen.raterman@gmail.com" rel="nofollow" target="_blank">gretchen.raterman@gmail.com</a>> wrote:<br></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" class="ydp8b565598yiv8277948584gmail_quote"><div dir="ltr"><div>Thank you for pointing that out! I'll update the group. Someone else sent me a Canadian paper that states 11.2 for 1st HVL and 15.2 for 2nd. So all this makes more sense!!</div><div><div dir="ltr" class="ydp8b565598yiv8277948584gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><p style="text-align:left;"><font face="tahoma, sans-serif"><span style="font-size:small;">Gretchen R. Bell, M.S., DABR</span><br><font size="2">Diagnostic Imaging Physicist</font><br><font size="2">Ochsner Medical Center</font><br><font size="2">(504)842-8506</font></font></p>
<p style="text-align:left;"><span style="font-size:10pt;font-family:Candara, sans-serif;"></span></p></div></div></div></div></div></div></div></div></div></div></div><br></div><br><div class="ydp8b565598yiv8277948584gmail_quote"><div dir="ltr" class="ydp8b565598yiv8277948584gmail_attr">On Thu, Apr 16, 2026 at 2:55 PM Reagan Dugan <<a href="mailto:rdugan1102@gmail.com" rel="nofollow" target="_blank">rdugan1102@gmail.com</a>> wrote:<br></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" class="ydp8b565598yiv8277948584gmail_quote"><div dir="ltr"><div>Hi Gretchen, </div><div><br></div><div>If I'm reading the Stabin paper correctly, they didn't combine emissions from parent/daughter, so that HVL for Pb-212 would only be accounting for the Pb-212 gamma emissions (238 keV mostly). If you scroll down the list a bit to Tl-208, the HVL is 15.5 mm, which makes more sense to me given the number of emissions and energies.</div><div><br></div><div>I haven't had to do shielding designs for alpha emitters yet, but I'd probably base the design off the Tl-208 data since those are the primary gammas used for imaging. Trying to account for the entire decay chain will probably require monte carlo simulations and another task group. I'd also double check to make sure you use the correct half life for Tl-208 since there's equilibrium issues at play.</div><div><br></div><div>For our clinical trials here we've just been using one of our pluvicto rooms in PET which were shielded for F18 before any of the theranostics stuff took off. We haven't gone through the math yet, but I think we're operating under the assumption that the workload for the trials is so low that the existing shielding is fine. For newer rooms we've just been assuming a full workload of Lu-177 therapies using the TG-313 archer coefficients. </div><div><br></div><div>If you end up working through the math for the alpha emitters, I'd love to see what you come up with if you're willing to share. </div><div><br></div><div>Good luck!</div><div><br></div><div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><b><span style="color:black;">Reagan Dugan, PhD</span></b><span style="color:black;"></span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">Imaging Physics Resident</span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">Department of Radiology</span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">The University of Chicago Medicine</span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">5841 S. Maryland Ave. | MC 2026 | Room M-529</span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">Chicago, Il 60637</span></font></p></div><div style="color: rgb(0, 0, 0); font-family: Aptos; font-style: normal; font-weight: 400; letter-spacing: normal; text-indent: 0px; text-transform: none; word-spacing: 0px; text-decoration-line: none; text-decoration-style: solid;"><p style="margin:0in;font-family:Aptos, sans-serif;" class="ydp8b565598yiv8277948584MsoNormal"><font size="2"><span style="color:black;">Office: 773-702-1220</span></font></p></div><br></div></div><br><div class="ydp8b565598yiv8277948584gmail_quote"><div dir="ltr" class="ydp8b565598yiv8277948584gmail_attr">On Thu, Apr 16, 2026 at 2:14 PM Gretchen Raterman Bell via Intl_dxmedphys_wd_osu_list <<a href="mailto:intl_dxmedphys_wd_osu_list@lists.osu.edu" rel="nofollow" target="_blank">intl_dxmedphys_wd_osu_list@lists.osu.edu</a>> wrote:<br></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" class="ydp8b565598yiv8277948584gmail_quote"><div>
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Greetings! I am dipping my toe into shielding requirements for theranostics. One of the hot new isotopes of course is Pb-212. I had looked at its decay chain a while back and saw a rather high-yield MeV emission from its daughter Tl-208 and</div>
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<div dir="ltr"><div>Greetings!</div><div><br></div><div>I am dipping my toe into shielding requirements for theranostics. One of the hot new isotopes of course is Pb-212. I had looked at its decay chain a while back and saw a rather high-yield MeV emission from its daughter Tl-208 and figured we could forget about a reasonable amount of lead. We'd have to use time and distance. HOWEVER today, I thought to look at the Smith and Stabin paper that lists 1000+ isotopes with their gamma rate factors and HVL, etc. data. Pb-212 is listed as having an HVL of only 0.756 mm Pb, which is about 1/7th the HVL they list for F-18! I understand that F-18 is almost 100% positron decay, but I still find this difference in HVL incredible.</div><div><br></div><div>Before going down a wild rabbit hole, I figured I'd probe the list for any other insights into Pb-212. We are starting a clinical trial soon using it, and I've been tasked with writing up a Radiation Safety SOP. In addition, we are doing a reno of one of our NM departments, and they would like to add dedicated theranostic injection rooms... so trying to see what kind of lead to put in the walls. (It's truly an impossible task, but I'm giving it my "college try.")</div><div><br></div><div>Many, many thank yous in advance.</div><div><div dir="ltr" class="ydp8b565598yiv8277948584gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><p style="text-align:left;"><font face="tahoma, sans-serif"><span style="font-size:small;">Gretchen R. Bell, M.S., DABR</span><br><font size="2">Diagnostic Imaging Physicist</font><br><font size="2">Ochsner Medical Center</font><br><font size="2">(504)842-8506</font></font></p>
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