Is there a listing available of all of the modality abbreviations?
Yes they are listed here.
Questions About Searching
How do I search images?
The NBIA software enables you to search for images in The Cancer Imaging Archive's local in vivo image repository. See Chapter 2 of the TCIA User's Guide for more detailed instructions.
The collection descriptions provide the best source of information about what disease was studied. On the search-images page, scroll down to the Collections block, and click on the question-mark to the left of the collection name. Click to see a brief description of the collection, usually with pointers to a site where more detailed information about the collection is available.
Questions About Downloading Images:
How do I download annotated image files?