[Intl_DxMedPhys] [External] NM uniformity flood to ACR

[Palmer, Matthew R. (BIDMC - Radiology)]

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Brian,

ACR will accept either the intrinsic or extrinsic flood.  You mention resubmission.  There are two situations - if something is caught in the administrative review, the ACR staff contacts you and you get to swap the offending material.  It should be no problem to change from intrinsic to extrinsic, just highlight that that's what you're doing in an email.  If it's a failure and you are resubmitting - this is a reboot and you can do what you like, there will be a new site scan data sheet to fill out.

As for intrinsics and a small room - it's hard to imagine.  If the room is big enough for the camera, the heads to rotate and the collimator changer and patient to get in and out then it should be big enough for an intrinsic flood.  The dogma says 5 fields of view or something like that.  You can get away with less.  If your point source is about six feet from the detector, you should be fine.  I know some physicists who hang in on the P-scope boom.

Matt


Matthew R. Palmer, PhD, DABR 
Director, Medical Imaging Physics, Department of Radiology 
Assistant Professor, Harvard Medical School 
Beth Israel Deaconess Medical Center 
330 Brookline Avenue 
Boston, MA 02215 
office: 617-667-0176 fax: 617-667-2770
mobile: 617-794-1736 pager: 617-632-7243 #32214



-----Original Message-----
From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu> On Behalf Of Brian Methe via Intl_dxmedphys_wd_osu_list
Sent: Thursday, October 30, 2025 9:39 AM
To: intl_dxmedphys_wd_osu_list at lists.osu.edu
Subject: [External] [Intl_DxMedPhys] NM uniformity flood to ACR

Good Morning:

In an ACR accreditation submission for a Siemens Symbia imager, the reviewer did not like the uniformity image. This flood was performed with a Tc-99m point-source. Source/imager distance or source/imager alignment were stated as possible causes. ACR instructions explicitly prohibit the submission of a curvature corrected point-source flood, the daily QC procedure for these imagers. No problem, I don’t love black-box corrections either. However, if distance/alignment was an issue on the first try, they could be an issue during the second, especially in a small imager room. The ACR’s instructions allow Co-57 floods which implies a sheet source. Well, experience in these situations has taught to confirm and not assume and thus have to repeat. So, when asked to confirm that a Co-57 sheet source uniformity flood was acceptable for this re-submission, the answer from the ACR was equivocal. I am hoping someone has a better answer: can a Co-57 sheet source be used to provide a uniformity flood image for ACR accreditation when Tc-99m point-source floods were originally submitted?

As the goal is to demonstrate uniformity, I believe the answer is “yes”. But, the ACR is at times inscrutable. And as I have stated, twice bitten, always shy.

If you have gotten this far, thank you.

Brian.M. Methe'

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