Modality and SOP class UID tag for fused SPECT/CT images

  • Hello.


    Have some questions about DICOM files.


    What is the correct value for the element (0008,0060) 'modality' tag when the files are of fused SPECT/CT images? Currently it's labelled with 'CT', but the images are because of that being referred to as a regular CT scan of the chest. As they need to be seen by specialist in nuclear medicine it seems more appropriate that they're labelled with NM. What is correct according to DICOM standard?


    The SOP class UID used was that of 'secondary capture image'. Is that correct?


    The images are more spesifically fused SPECT/CT scan of the skeleton of thorax. Part of lumbar spine also visible.

  • Whereby "SC" is no defined DICOM term for the modality attribute (0008,0060) and picky stations may refuse them or may not allow to search for this modality marker. We label secondary capture images as "OT" (other title) by default. But, AFAIK, there is no reason, why you shouldn't be able to mark the fused images as "NM" as well, if that makes it easier in your reading workflow. It's just important to note that the secondary capture SOP class is a limited one and that those images often do not provide all information that you would find in a CT image, for instance. Like missing position or pixelspacing information.


    Your nuclear medicine specialists should find the study due to the SPECT images being labeled "NM". They would have to look at all the images anyway - CT, SPECT and fused. Or do you store the different types of images in different studies?