The CTP Lookup Table Editor

This article describes how to update the DICOM Anonymizer lookup table to manually assign subject IDs in clinical trials. The intended audience of this article is clinical trial administrators and coordinators.

In some clinical trials, subject identifiers are manually assigned before images are acquired and processed. In such trials, the DICOM Anonymizer is configured to convert the text stored in the PatientID element of an image into a non-PHI subject ID. CTP provides a Lookup Table Editor web page for assigning the subject IDs. This page can be accessed by any user with the CTP admin privilege.

To access the page, log in as an admin user and click the Lookup Table Editor button on the home page. A page will load, listing all the anonymizers that have lookup tables in the configuration. Click on the desired lookup table. A new page will load, listing all the values currently in the table and providing a row to add a new value:

Error creating thumbnail: Unable to save thumbnail to destination

Because the lookup table can be used for mapping many types of elements, each type of element is assigned a keytype by the administrator who configures the DICOM anonymizer script for the trial. The keytypes that appear in the anonymizer script are shown on the Lookup Table Editor page for convenience.

When adding a key to the table, enter the keytype, a forward slash, and the PatientID value in the left field and the subject ID in the right field; then click the floppy disk icon in the upper right corner of the window body or the "Update the file" button at the bottom of the page.

For convenience, the two triangle icons on the right side of the pane allow the lookup table to be downloaded to or uploaded from a spreadsheet in CSV format. The recommended procedure is to download the lookup table, open it with the spreadsheet program, add as many subjects as desired, save the spreadsheet as a CSV file, and then upload it to the Lookup Table Editor. When adding rows in the spreadsheet program, column A contains KeyType/PHI values andc column B contains replacement values. No title row is allowed.

IMPORTANT NOTE: The lookup table is used during the processing of DICOM images. After an image has been processed, subsequent changes in the table do not affect it. Therefore, it is not a good idea to modify entries that have already been used to process images. Doing so might assign the same subject ID to multiple subjects.