Here is some sample code on how to get Dicom Attributes or metadata out of the Dicom file.
//With DICOM support built in you can just set the source to dicom and then do a get node to the attribute you want.
//Use Shift F4 to lookup any dicom codes
var studyInstanceUID = message.getNode("0020,000D");
var seriesInstanceUID = message.getNode("0020,000E");
var objectUID = message.getNode("0008,1155");
var transferSyntax = message.getNode("0002,0010");
// Build a WADO Url
var wadoUrl = channelCache.getValue('baseWadoUrl');
wadoUrl += "requestType=WADO" +
"&studyUID=" + studyInstanceUID +
"&seriesUID=" + seriesInstanceUID +
"&objectUID=" + objectUID +
"&patientID=" + messageCache.getValue('pixId') +
"&patientIDAuth=" + messageCache.getValue('uniqueRepId');
As mentioned you have the Dicom Code lookup dialog: