As part of the recent Radiotherapy DICOM service migration at Raigmore hospital, Pukka-j set up the new DICOM Anonymisation service that is built on Nexus (DICOM Streaming Service) to allow the department to anonymise data for clinical trials.  The DICOM anonymiser operates on the header information in the DICOM files as they pass through the node.  Specific anonymisation rules can be configured based on the called AET, referred to as the “Trial AET” within the anonymiser.  Because some systems may have had the original data, if they receive the anonymised data with the original UIDs unchanged, then it is possible the original demographic data will be displayed by such a system as it has cached those details for the original UIDs.  This is handled by the anonymiser by selecting to re-UID the DICOM header.  A record is kept of the original and new UIDs as a look-up.  This allows any cross-referencing using UIDs between DICOM files to be maintained, such that, if the system finds a UID it has replaced for the selected trial in the past, it uses the same one again.  This allows DICOM objects such as RTPLANs to maintain a reference to an anonymised CT series, even after UIDs have been replaced.

You can download the Nexus specification document here [Download not found]
You can see more on Nexus here