For twenty years a radiology reading room had a simple rule: if you wanted to look at a CT properly, you sat at the workstation. The one with the licence, the special graphics card and the IT ticket attached to every update. Everyone else got a thumbnail in the HIS or a CD.
That rule is gone. Modern browsers ship with WebGL, a hardware-accelerated graphics layer that was built for games and turned out to be exactly what medical imaging needed. A 600-slice CT can be windowed, scrolled and reconstructed in three planes on an ordinary laptop, with nothing installed.
What actually changed
- Rendering moved to the GPU in the browser. Window/level, zoom and cine are computed locally at 60 frames per second instead of being repainted by a server for every mouse move.
- Heavy work moved to the server. Volume rendering, MIP and curved reformats of a large series are computed centrally and streamed as images, so the client never needs a workstation-class card.
- Studies stream instead of download. The first slice appears in under a second; the rest arrives in the background while the reader is already looking.
What it means for a department
The number of places a study can be read stops being a licensing question and becomes a network question. A referring surgeon opens the same viewer the radiologist used, on the ward, with the radiologist's annotations already in place. An on-call reader at home sees the case at full diagnostic quality through a secure link. A second opinion is a URL, not a courier.
It also changes the economics. There are no per-seat installs to maintain, no drivers to certify, and a new user is an account rather than a purchase order.
Where RadImages fits
RadImages Web Viewer was designed around this split from day one: WebGL on the client for everything interactive, server-side rendering for everything volumetric. It ships as part of every RadImages PACS licence and as a standalone product that connects to an existing archive over DICOM, so a hospital can put a modern viewer in front of the PACS it already owns.
The next article looks at what happens to a study in the sixty seconds after the scanner finishes, and where those seconds go.