[Intl_DxMedPhys] TJC acquisition monitor requirements

[Little, Kevin]

Hi Doug,

We use the TG-18<https://urldefense.com/v3/__https://aapm.onlinelibrary.wiley.com/doi/10.1118/1.1861159__;!!KGKeukY!0hVAGTUjL-BxQi0GIhsZuSFfh59iAhpgWI1vKOimiDD_9gfyZBTnfpan8_PGl7dnBR-TJ4IoQK8vDxyNoL4pVVJbz2xD2zcFDCS5LScxhcgpylc$ > geometric distortion test. Essentially, we are looking for an incorrect aspect ratio (which we have found, especially for replacement monitors). We use a ruler to measure the same number of squares on the SMPTE or TG-18 QC pattern in both directions. Then we calculate the percent difference, using the smallest measurement as the reference. TG-18 says that operator’s consoles are secondary displays for everything other than contrast response, so the limit is 5%.

Kevin


Kevin J Little, PhD, DABR, DABSNM, CIIP
Associate Professor
Imaging Medical Physics Residency Program Director
The Ohio State University Wexner Medical Center
Department of Radiology
395 W 12th Avenue, 4th Fl, Columbus, OH, 43210
ImagingPhysics at osumc.edu<mailto:ImagingPhysics at osumc.edu>
On-call Physicist: Internal link<https://webxchange.osumc.edu/webxchange/ViewProfile.aspx?profileid=08701 > or call 614-293-7243,8701#


From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu> On Behalf Of Douglas Pfeiffer via Intl_dxmedphys_wd_osu_list
Sent: Wednesday, September 23, 2026 8:31 AM
To: DxMedPhys List <intl_dxmedphys_wd_osu_list at lists.osu.edu>
Subject: [Intl_DxMedPhys] TJC acquisition monitor requirements

Good morning! I just received a document to prepare us for upcoming TJC inspections. It includes the following: My question is about the last item - spatial accuracy. I’ve never measured spatial accuracy on an acquisition display, and I don’t
Good morning!

I just received a document to prepare us for upcoming TJC inspections. It includes the following:
[cid:image001.png at 01DD4B3D.F162B890]

My question is about the last item - spatial accuracy. I’ve never measured spatial accuracy on an acquisition display, and I don’t remember anyone ever talking about it. The only time I could imagine it being an issue at all is during MR- and CT-guided biopsies, but that is accuracy of the system calipers and not a function of the display. What are folks doing with this one?

Best regards,
Doug



Douglas Pfeiffer, MS, DABR FACR, FAAPM (he/him)
Medical Physicist, Radiation Safety Officer
Boulder Community Health
xraydoug at me.com<mailto:xraydoug at me.com>
303.415.7515

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The opinions expressed in this message are the product of the gray and white matter loitering in my cranium. I speak for myself and no one else, unless I say otherwise.

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