“Proposed” VA PACS DVD-R DICOM Archive Requirement Peter M. Kuzmak Department of Veterans Affairs Silver Spring, Maryland

VA’s Own Requirement: Store Reports & Images Forever Xray Film (and Mammography Film) –5 (10) years from date of last activity –10 years from date of military discharge Patient’s Medical Record - 75 years –Reports and Interpretations –Digital Images

Requirements for Long-term Interchangeable Image Archive High density, long shelf life, fast access Long technology life span –Relatively immune to technology obsolescence Portable, Standards Based, low cost –Assumed to use DICOM DVD-R –Store interpretations, reports, and images –Interpretations and Reports stored as SR objects Supported by all PACS vendors

Interchangeable Image Archive The II Archive would be an add-on to the existing architecture of all PACS Every PACS vendor would have the ability to “import from” and “export to” the II Archive Daily, PACS vendors would write reports, interpretations, and images to the II Archive –Written in chronological first-in-first-out order PACS vendor would use a large jukebox to hold media to automate the II Archive

Helps Migrating Between PACS’s Sooner or later, every PACS customer will consider upgrading their PACS What do you do with the images on the old system? Copy images from the old system to the new system over the network? –One estimate: 1 year to copy 5 years of images Solution(?): Bulk transfer of II Archive media from the old system to the new

Three-Fold Insurance Plan for VA Provides redundant data backup in case of catastrophic system failure Enables the data to be carried over through major PACS equipment upgrades and database merges Facilitates data migration from one PACS vendor to another

Changing PACS systems should be no more complicated than changing houses! Pack-up all your stuff Move it Unpack it Setup house again Those things that you use most often, you pack last and unpack first

Changing PACS Systems (A Possible Scenario) With old system operational, transfer old II Archive media to the new system Load old II Archive media into new II Archive Create new patient/study II Archive indexes Stop processing new studies on old system Flush all new studies to II Archive media and transfer them to the new system Load final studies from old system into new Start using the new system

Potential Implementation Proposal Design Goals As much as possible Patient & Study information needs to be on media Organized in human/machine readable format –Media should be able to be placed into a PC and be humanly navigable –Should be able to be read very quickly by a automated computer application -- Scan the disk and determine contents w/o reading every file Data should be useful 75 years from now

Optimize Directory Organization DVD-R’s once-write characteristic presents an opportunity to organize the data in the staging area so that it has an optimal directory structure on the media for this application.

Potential Directory Layout Patient Name + ID (one unique directory for each patient) Date/Time + Imaging Service Request Description (may be expanded to include normal/abnormal flag, summary results, etc.) Requested Procedure Description + CPT Code Modality Performed Procedure Step Images (stored under SOP Instance UID) Ordering Information and Structured Reports Patient Demographics DVD-R media is labeled with institution name and date-range

Potential II Archive DB Schema Patient (on PACS db) 1:n Archive Media Disk ID Patient Name + ID Requested Procedure Imaging Service Request Ordering Information and Structured Reports Images Modality Performed Procedure Step 1:n 0:n

Potential II Archive DB Schema Patient (on PACS db) 1:n Archive Media Disk ID Patient Name + ID Requested Procedure Imaging Service Request Ordering Information and Structured Reports Images Modality Performed Procedure Step 1:n 0:n Portion of II Archive needed to populate PACS database

PACS Database Index of Patient’s II Archived Studies

DICOM Working Group 5 Issues Keep DICOMDIR Use CD-R (DVD-R to-be) general purpose application profile Implement II Archive using DVD-R Follow proposed file/directory name convention Expand 8-Character DICOMDIR file name, maybe to 255 characters

Other Uses for DVD-R (besides Interchangeable Image Archive) Patient File Transfer (“Patient File”) –Selective transfer of information between different facilities –Works even if the different facilities use PACS provided by different vendors Take Home Medical History (“Film Jacket”) –One or more studies on media –Patient supplied with electronic copy of medical record