The CTP DICOM Anonymizer Configurator

CTP includes a DICOM anonymizer which can be configured to modify DICOM objects according to a set of scripts defined by the system administrator. This article describes how to use the configuration servlet. It is intended for administrators.

Background

A CTP pipeline may contain anonymizer stages for any of the object types that CTP recognizes (DICOM, XML, and Zip). In some situations, there may even be multiple anonymizers for objects of the same type. Each anonymizer stage is controlled by its own script file, making it possible to modify objects in different ways as they proceed down the pipeline.

The CTP DICOM anonymizer is configured by an XML file containing elements of four types:

• Parameters provide global text values that may be referenced by name in scripts for DICOM elements.
• Elements contain script commands for individual DICOM elements.
• Keep commands indicate whether all elements in a DICOM group are to be globally kept in the anonymized object.
• Remove commands identify certain element or group types which are to be globally removed while producing the anonymized object.

The CTP DICOM Anonymizer provides detailed instructions on how to write scripts for individual elements.

The DICOM Committee has published Supplement 142, Clinical Trial De-identification Profiles, which defines several collections of rules for anonymization under various conditions. These collections, called "profiles", specify what must be done to achieve a condition's objective. The fundamental, and in most situations most stringent, condition is called the "Baseline Profile".

The CTP DICOM Anonymizer Configurator implements the concept of a profile as a script file containing only those parameters, elements, keep commands, and remove commands which are relevant to the objective of the profile. A profile is said to be "applied" to a script, modifying only the items in the script which are in the profile. Any items in the script which are not in the profile are not modified when the profile is applied.

The NCI is developing CTP profiles to implement several of the Supplement 142 profiles. The Baseline Profile has been released and is included in the most recent CTP version. This profile is intended to meet HIPAA privacy regulations. Other profiles will be added to the CTP release as they are developed.