Dose grid scaling

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Renata Chmielewski

Apr 7, 2021, 11:24:14 AM4/7/21
to pinnacle3-users

I am exporting RT dose and RT plans from Pinnacle to use in 3D slicer. The Dose Grid Scaling parameter on the RT Dose files is set really low 5.6e-04. This is an issue because when I apply a scaling factor in 3D slicer the dose is not correct because I can't apply a scaling factor with 3 or 4 decimals. How does the dose grid scaling parameter work in Pinnacle? How do I change it? Thank you!


Lukas Wi

May 8, 2021, 5:07:50 AM5/8/21
to pinnacle3-users

Hi Renata,


I don't know whether you actually can change the dose grid scaling value in Pinnacle. Instead, if you are familiar with Python, you could try to read the RT Dose file using pydicom, then modify the scaling according to your needs, and save the result as a new RT Dose file.

Reading the dose in Gy from the RT Dose file could look like this:

import pydicom

dcm = pydicom.read_file( rtDoseFileName )

doseGy = dcm.pixel_array * dcm.DoseGridScaling


where rtDoseFileName is your exported RT Dose file name and doseGy contains the dose matrix in Gy. Then you may modify the DoseGridScaling factor and pixel_array values according to your needs and write a new RT-Dose file.

I haven't tried this second part myself, but If that works as expected,  you should be able to import the new RT-Dose file to 3D slicer. 


Best regards,

Lukas Wissmann

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