Planar image analysis - DoseLab phantom

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Hello all,

I’m having an issue with the results provided by Pylinac when I perform planar imaging analysis with the DoseLab phantom: sometimes, I get some really wacky results (i.e. a negative spatial resolution).

Here is my code:
image.png

For the attached “good” image (the one that is giving reasonable results), the reported spatial resolution is 1.01 lp/mm.
For the attached “bad” image (the one giving weird results), the reported spatial resolution is -11.24 lp/mm.

The images were taken with the same techniques, with the same setup.

Has anyone had similar experience with this? I’ve attached the DICOM files themselves, as well as some results plots.

Thank you!

~Alex

good_image_low_contrast.png

good_image_high_contrast.png

bad_file_high_contrast.png

bad_file_low_contrast.png

good.dcm (3.13 MB)

bad.dcm (3.13 MB)

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What pylinac version are you using {print(pylinac.version)}? Here’s what I get with v3.0 for bad.dcm

Figure_1.png