SNC MV QA phantom

Good afternoon,

Been working on my planar imaging QA. Was able to successfully run the Leeds and LasVegas Tests. Trying to get the SNCMV phantom to run.

Phantom is on the Jig with gantry at 270. Tried the phantom at every position. Could not find the phantom in any of the 4 positions. Tried changed ssd in the analyze command with no luck.

My script is:
from pylinac import SNCMV
SNCMV = SNCMV(r"C:\Users\Caitlin\2D\Images\MVQA.dcm")

SNCMV.analyze() #added the ssd=1000 and other options to try to get to work

cannot get past this step.

Any advice or help.



Follow up on my SNC MV phantom Analysis.

I setup using 100 SAD, so changing to 90 SSD in the analysis command allowed it to run.

As you can see in the attached image, pylinac does not find the iso. I doubled checked my setup and is aligned correctly and the digital graticule lines up with the phantom correctly. Also, you can see, the blue box is not aligned…Looks to be more of a square, and not a rectangle as the image area appears to be.

Any thoughts on what to try next?




This looks a bit different than the demo image. Note the outer shroud is thicker on one side than the other in your image but is thick on both sides of the demo image. I’m guessing there are multiple versions of this phantom? Can you send me some pictures of the phantom and label as well as some DICOM images? If it’s a new or different version I’ll have to add its own variant.


Im out of the clinic till Monday. I’ll get pictures on Monday. I’ll also run the demo to take a look at it when I’m in office.



Here are the images of my SN MVQA phantom.

Thanks for your help.



MVQA.dcm (804 KB)


I forgot this was the phantom that there is an “old” version of. Use the SNCMV12510 class.

from pylinac import SNCMV12510

snc = SNCMV12510(…)

That did it. Thanks.

I thought I had tried that phantom also, but I think I forgot to update/change one of my commands in the script when I tried it.

Here is the result…The only thing off is the crosshair, everything else lines up.

Thanks for your help.