All,
I have some DICOM files from a pet scan and an MRI. I viewed the files in three different ways:
1. Opened the DICOM's directly in a viewer (Pmod) 2. Used mri_convert to change the DICOMs to a .nii, and opened them. 3. Used dcm2nii to change the DICOMS to a .nii and opened them.
It's my intuition that the raw intensity values are displayed when I directly open the DICOM images. However, both step (2) and (3) give images with intensity values scaled--(2) scales by different factors depending on the modality, anywhere from 16 to 50; (3) scales by a fixed amount (two orders of magnitude, possibly understandable).
The images are indistinguishable when the levels are set properly, so this scaling would appear to be a flat linear multiplier. I'd like to know where it comes from--is there some information in the DICOM headers that mri_convert is using to scale things?
I checked the archives of this mailing list and found the tag -ns 1, but this didn't change the output file at all.
Any help is appreciated.
-- Quentin Funk, PhD Houston Methodist Research Institute 713-363-9003
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