In IDL converting images from other formats to DICOM involves the following steps: Step 1: Import the other image files into a 2D or 3D IDL image array variable. Step 2: Create (and open) a general DICOM output file with an initialization call to the IDLffDicomEx class, e.g.: oDicomImage = OBJ_NEW('IDLffDicomEx', 'aMRImg.dcm', $ SOP_CLASS = 'STANDARD_MR', /CREATE, /NON_CONFORMING ) Step 3: Use the 'IDLffDicomEx::SetPixelData' method to assign the image data from step 1 to your new DICOM file "object". Step 4: Call 'IDLffDicomEx::Commit' to write the 'IDLffDicomEx' object's properties out to its file, e.g.: oDicomImage->Commit Step 5: As with all objects, when they are done doing their work, destroy the object, e.g.: obj_destroy, oDicomImage An example of exactly the above, of exactly what you want to do, is shown in the IDL Online Help for the 'IDLffDicomEx::SetPixelData' method. Click on the 'Examples' link at the top of that Help page, or just open: '.../[your IDL root directory]/examples/doc/dicom/dicomex_importimage_doc.pro' Note that users need a 'dicom_rw' DICOM Read/Write license in order to initialize an 'IDLffDicomEx' object