Hanging protocols are a means of defining how images should initially be displayed to a user. They are otherwise known as “user display profiles” or “default display profiles”, and have existed as proprietary systems for many years, but a vendor-neutral DICOM method for creating, storing, and retrieving them was finally agreed. Unfortunately, uptake in the real world has been very limited.

What they use

Hanging protocols are actually quite complicated, as there are so many variables to consider:

• Types of current images
• Number of current images
• Number and type of previous images for comparison
• Number and type of monitors available for display
• The user (as each may have different preferences)

The DICOM solution

After many years of discussion, DICOM supplement 60 was finally agreed, which stores the objects using the normal C-STORE, C-FIND & C-MOVE mechanisms, but with “fuzzy logic” in the SCP (to be designed by the SCP manufacturer!) to find the best match. These objects have their own Q/R model which is a single “Flat” collection, unrelated to the normal patient or study root models.

Use In DicomObjects

It should be possible to create, send, store and retrieve these objects using existing DicomObjects mechanisms, the only slight modification needed being to set the “Root” property to the UID required:

• 1.2.840.10008.5.1.4.38.2 for C-FIND operations
• 1.2.840.10008.5.1.4.38.3 for C-MOVE operations

Of course, interpretation the contents of the objects is a job left to the developer!