ACR Large Phantom Help

Hi,

Thanks to the team for the great work on pylinac!

I’m having some trouble running the ACR Large Phantom module, I have tried a combined file format, where all the series images for a given T1 or T2 sequence are in the same file with a separate localizer and also with them in individual files. I keep getting the error below.

I see in the ’ pylinac.core.image’ webpage, min_number =39.

Could you tell me what should be contained in the folder? Please and thank you.

File “C:*\Documents\PythonProj\QACT\MRIqa.py", line 4, in
mri = ACRMRILarge(acr_mri_folder)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:*
\AppData\Local\Programs\Python\Python312\Lib\site-packages\pylinac\ct.py”, line 1669, in init
self.dicom_stack = stack(
^^^^^^
File “C:*\AppData\Local\Programs\Python\Python312\Lib\site-packages\pylinac\core\image.py", line 1798, in init
super().init(folder, dtype, min_number, check_uid)
File "C:*
\AppData\Local\Programs\Python\Python312\Lib\site-packages\pylinac\core\image.py”, line 1662, in init
most_common_uid = self._get_common_uid_imgs(metadatas, min_number)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:****\AppData\Local\Programs\Python\Python312\Lib\site-packages\pylinac\core\image.py”, line 1692, in _get_common_uid_imgs
raise ValueError(
ValueError: The minimum number images from the same study were not found

Hi,
I haven’t worked with the phantom or module myself, but the error in the last line printed is “The minimum number images from the same study were not found”

According to the documentation you need 11 slices per scan:
https://pylinac.readthedocs.io/en/latest/acr.html#restrictions

Maybe you are missing one slice.

1 Like

Thank you Tommes,

My folder has 11 from the same series. I tried it with the 11 all in dicom file, and separated. In the code (pylinac.core.image), I couldn’t see reference to 11 as min_number. Where would it pull the 11 from?

Thanks.

Hi,
the number of slices is fixed in the class. For example the analyze method uses the reference to slice 1 and 11: pylinac.acr - pylinac 3.25.0 documentation

If you do have 11 images in your series, then maybe there is another problem.
You could check if the single images have the same series instance uid. The error is raised from “self._get_common_uid_imgs(metadatas, min_number)” so maybe some uids are missing.

1 Like

Thanks Tommes.
All seires instance UIDs are the same as attached.

I have used both the folder where the files are contained and where the dicomdir is contained. Both with the same error.

***Edit: Tommes, thanks for your help. It is now working. I think local restriction to file server were causing the issue.