Dicomatic from Tomovision at tomovision.com might be useful for this. Alternatively convert back to GE, Siemens, Bruker,.. and then use their tools for converting to DICOM.
Also you might want to look at the DICOM Import and Export Plugins for NIH's ImageJ. ImageJ is found at rsb.info.nih.gov; the DICOM plug-ins are available at www.iftm.de/dicom/dcmimex.htm .
Matlab has the dicomwrite function in the Image Processing Toolbox too. www.mathworks.com
Osirix is available for older Macs and OS X and can read and write DICOM. homepage.mac.com/rossetantoine/osirix/Index2.html
DICOMaccess is an Adobe Photoshop plug-in that can create DICOM image files from www.desacc.com.
Leadtool Medical Imaging toolkit can read and write DICOM. www.leadtools.com/sdk/raster/formats/raster-format-dicom.htm.
MedXpress from Pegasu Imaging reads and writes DICOM. www.pegasusimaging.com/medxpress.htm
There is the IDL DICOM toolkit from RSI at www.rsinc.com.
Also the DICOM image I/O java plugin from imaging.apteryx.fr/dicom
www.snowbound.com has various products for writing DICOM including RasterMaster and SnowBatch.
Finally numa at numa-inc.com has various tools for reading and writing DICOM.