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openneuropet / PET2BIDS

PET2BIDS helps you convert your PET data into BIDS! raw PET scanner files (e.g. ecat, dicom) and additional side files like .e.g excel sheets -- paper @JOSS https://doi.org/10.21105/joss.06067
https://pet2bids.readthedocs.io
MIT License
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24 hour time #322

Open neurolabusc opened 4 weeks ago

neurolabusc commented 4 weeks ago

The terrific validation dataset provides both the input DICOMs as well as the reference conversion to BIDS.

I notice there is an error for TimeZero in the file sub-GeneralElectricSignaAarhus_pet.json. The DICOM image suggests this is at 1pm using 24-hour time format:

(0008,0031) TM [134653]                                 #   6, 1 SeriesTime

but the JSON suggests 1am (12-hour format does not disambiguate morning or afternoon).

"TimeZero": "01:46:53",
neurolabusc commented 4 weeks ago

I also think there is an error in this InjectedRadioactivity

  "InjectedRadioactivity": 21,
  "InjectedRadioactivityUnits": "MBq",

I believe this should match DICOM Radionuclide Total Dose (0018,1074) which is defined as MBq:

    (0018,1074) DS [      20924990]                         #  14, 1 RadionuclideTotalDose

The pet2bids source code is converting megabecquerels (MBq) to gigabecquerels (GBq). So the results should either be:

  "InjectedRadioactivity": 20924990,
  "InjectedRadioactivityUnits": "MBq",

or

  "InjectedRadioactivity": 21,
  "InjectedRadioactivityUnits": "GBq",

I suspect the source of this issue is the developer assumed that the DICOM RadionuclideTotalDose is defined in Becquerels, but it is actually megabecquerels.