[Intl_DxMedPhys] AAPM TG 126 reference for Vendor's sensitivity values?

[Josh M Wilson]

In case anyone is interested, I never did hear back from anyone with AAPM TG 126 about where these values came from.

Doing my own digging, here is what I found:
To find out your system's Sensitivity and Activity Correction Factor ranges:

  1.
open a unix shell
  2.
cd /usr/g/PET/systemConfig/local
  3.
more cal.cfg (this is actually a symlink to a file that matches your system configuration)

You can also grep for any of these strings (the asterisks aren't wild cards, it's GE's delimiter for the config file):
      wcc*minActivity
      wcc*minActivity
      wcc*min2DActivityFac
      wcc*max2DActivityFac
      wcc*min3DActivityFac
      wcc*max3DActivityFac
      wcc*minSensitivity
      wcc*maxSensitivity
      The console contains a collection of config files for different models and detector configurations. I grep'ped for a few of the above strings for Activity Correction Factor ranges, and have attached a picture of the output.
    AAPM TG 126 simply lists the GE Vendor Limit Mean (Range) of 2.0-12.0, but that is for just one detector model. Other acceptable ranges include [0.01,5.16] or [1.95,7.80].

To see the values of the Sensitivity and Activity Correction Factors

  1.
open a unix shell
  2.
cd /usr/PET/release/dragon/bin/linux2
  3.
stardWcc 3d
  4.
The 3D Sensitivity and Activity Correction Image Sets browser window will display.
  5.
Select an image series.
  6.
Click OK.

The shell will update with text from WCC Senstivity and Activity

Best,
Josh M. Wilson, PhD

Duke University Health System
Radiation Physicist, Clinical Imaging Physics Group
Duke University, School of Medicine
Director, Duke Imaging Physics Residency Program
Assistant Professor, Department of Radiology
Duke University, Graduate School
Faculty, Medical Physics Graduate Program
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From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu> on behalf of Josh M Wilson via Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list at lists.osu.edu>
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Subject: [Intl_DxMedPhys] AAPM TG 126 reference for Vendor's sensitivity values?

In AAPM TG 126, "PET/CT Acceptance Testing and Quality Assurance", in the Sensitivity section, there are a couple of methods and vendors described. There is a table that lists vendor ranges, but I'm not sure where these values come

In AAPM TG 126, "PET/CT Acceptance Testing and Quality Assurance", in the Sensitivity section, there are a couple of methods and vendors described. There is a table that lists vendor ranges, but I'm not sure where these values come from. Does anyone know? I'm especially interested in GE.
[cid:dd2f62a9-257b-4b11-9ca2-04c307f1851a]

Further, in Appendix A.2, the first example for GE states:
"The activity correction factor should be displayed at the bottom of the graph (Figure A.5). GE specifies that this factor should be within 2.0 and 12.0, while the sensitivity correction factors shown on the graph per slice should be within 0.8 and 1.5."
But I don't know where those values come from. Interestingly enough, Figure A.5 shows a GE IQ scanner as an example and the highlighted activity correction factor is "1.07131" which is specifically outside the (2.0,12.0) range.


Best,
Josh M. Wilson, PhD

Duke University Health System
Radiation Physicist, Clinical Imaging Physics Group
Duke University, School of Medicine
Director, Duke Imaging Physics Residency Program
Assistant Professor, Department of Radiology
Duke University, Graduate School
Faculty, Medical Physics Graduate Program
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