Part 1: Answers to XDS/XDS-I webinar audience questions
Posted by Jackie Walsh on Thu, Feb 25, 2010 @ 11:41 AM
Dr. Bak's responses to audience questions are going to be added here as series of posts over the next day. Feel free to ask additional questions or add your opinion in the comments section below.
1.) Q: Are there free standing/independent imaging centers in Ontario? How do - Dan Banach, OAMRI, RIS/PACS Admin
A: Ontario has many independent clinics. The Ontario Ministry (eHealth Ontario) is looking at a business and technical model to integrate these clinics in to the existing infrastructures deploy and operating. The details of this are not public knowledge as of yet!
2.) Q: How do you communicate Usernames and passwords across multiple systems or do you require user to log into each system independently?
A: IHE offers a profile called XUA that details how to federate usernames and passwords. In practice this is essentially a federation of Active Directories…which falls outside of XDS-I and/or PACS. This is an IT task that is challenged more by governance than technology.
3.) Q: How is security handled e.g. how is ad hoc access to images in a hospital PACS facilitated (assuming said PACS is behind a firewall, etc)?
A: In any DICOM network one has challenges. If the image retrieval is via DICOM, you really have to deploy a VPN and open up the firewall to let DICOM traffic into the LAN. This is not desirable and usually addressed by putting the PACS in a dedicated hospital LAN..Even then IT gets nervous!
The alternate is to put a WADO server in a DMZ. External XDS consumers hit the WADO server over the WAN. The WADO server connects to the PACS on a separate LAN.
My experience so far is that all hospitals expect traffic to travel over a VPN. If combined with WADO, this provides an acceptable level of security.
My personal opinion is that we should develop capabilities that relegate DICOM to the LAN and leverage internet protocols for all transactions over the WAN. If done correctly, traffic can flow over both private and public networks. Such capabilities could augment XDS-I.
4.) Q: What is the cost to the outside hospital to place images in the repository to the tertiary hospital, if any?
A: Tough to answer! It all depends on what is in place and what extra you have to procure for the local site and for the XDS domain.
5.) Q: Not many facilities in the US enforce a Key Image policy for their reading radiologists. In light of that, do you advocate publishing a KOS containing every image in the study?
A: It all depends on the user case. For most of the use cases, you do want to publish the entire study. However, I would say that the pressure is now on to put key image notes in place as XDS offers up the opportunity to share to a much broader audience of consumers…who do not always want to wade through a full study. Pressure to offer better service will drive the shift to produce key image notes