Incorrect horizontal profile when loading SNC IC Profiler data

Bugs
1

It looks as though when importing IC Profiler data points are incorrectly assigned in the x-axis. I assume this is a bug related to the profiler not having detectors on the x-axis at -0.5 and +0.5 cm.
I am expecting perfect symmetry of the beam profile in the horizontal axis.

  • What version of pylinac are you using (pylinac.__version__)?
    3.2.0

  • I’ve read the documentation for this module?
    Yes

  • Post your code snippet

from pylinac import DeviceFieldAnalysis, Device
from pylinac import Protocol

my_file = r"C:\Data\6X_Sym.prs"
profile = DeviceFieldAnalysis(my_file, device=Device['PROFILER'])
profile.analyze(
    protocol=Protocol.ELEKTA,
    is_FFF=False,
    edge_detection_method=Edge.FWHM,
)
print(profile.results_data().protocol_results["symmetry_horizontal"])
profile.plot_analyzed_image()

Not sure how to attach my data file.

2

Hi,

what do you not like about your horizontal profile? To me it looks perfecly symetrical. The maximum to the profile is from both sides 8 measurement points. The measured value seems to be exactly the same on both sides.
Compared to the vertical profile the flatness seems to be greater but that could be just due to the different y-axis scaling.

regards
Thomas

3

Thanks for the reply.
The data has been symmetrized so it should be perfectly symmetrical.
The issue is that if you look at the response at detector 30 and 31 there is an error being introduced when being read by pylinac.
I believe the values for these two detectors should be swapped.

I think this being introduced by pylinac as the profiler does not physically have detectors at positions +/- 0.5 cm (detectors 31 and 33 in the image) and it is assigning the detector response for detector 31 instead of 30.