To share data between Slicer and Matlab, I would not recommend using DICOM, especially if you want to minimize information loss and you don’t have a clear idea how PK maps should be stored in DICOM in a standard-compliant way.
Probably the most forward-looking solution is to not bother with Matlab anymore and implement your analysis in Python. See tutorials here.
Second option is to use Slicer’s MatlabBridge extension, which allows running a function implemented in Matlab directly from Slicer (the bridge takes care of passing data between Slicer and Matlab).
Third option is to save the image to a nrrd file and manually read it into Matlab using nrrdread.m.