1851: The first World Expo, known as the Great Exhibition, was held in London. Visitors were enthralled by a new technology known as stereoscopy that allowed people to view photos in 3D. The technique soon became a huge success – and scores of photographers began traveling around the world to take snapshots of exotic destinations and imposing buildings using stereoscopic cameras. Now, anyone equipped with a stereoscope could travel to distant lands from the comfort of their own armchair, and by 1900 stereoscopy had already become a popular mass medium. It is no wonder, therefore, that the discovery of X-rays was quickly followed by the first experiments into stereo X-ray images.
Research into stereo X-ray imaging was prompted by the fact that X-rays could be deceiving. This is because a normal X-ray image depicts all the structures in a particular area of the body in a single plane, from the tissue to the bones to the organs. It took considerable experience to derive diagnostic information from the abstract collection of blurry shadows that made up an X-ray image. An evaluation of this kind often benefits from a third dimension: When the X-ray image is viewed in 3D, the individual structures move apart from one another, and it becomes clear that the ribs are in front of the lungs, for example. This can be achieved through the incorporation of stereoscopy, whereby two X-ray images are taken of the same part of the body one after another from slightly different perspectives. The two images in this “stereoscopic pair” are then presented to the eyes using special viewing techniques so that the brain can process them as a single three-dimensional image.
X-ray videos in 3D
1922: New York’s Selwyn Theatre became the first movie theater to use the Teleview system – invented by Laurens Hammond, this was a forerunner of the shutter technology now used in 3D television, for example. Synchronized viewing devices were attached to the armrest of each theater seat to provide the audience with an immersive viewing experience as they watched the 3D movie The Man from M.A.R.S. Perhaps this technique could also be used to view not only individual images but also an entire X-ray video in 3D?
Inspired by the shutter system, the company Siemens-Reiniger-Veifa subsequently launched a stereo X-ray device in 1927. The apparatus was fitted with two tubes that alternated to produce a moving image on a fluorescent screen from slightly different perspectives. The centerpiece of the device was a pair of “shutter glasses” that were responsible for the 3D effect. These were synchronized with the images and darkened each eye in turn so that the viewer could only see the image meant for the correct eye.
A virtual journey into the body
2014: The computer-animated mythical being Gollum provided the impetus for a development that marked a new era in 3D imaging. This character from The Lord of the Rings film trilogy gave the developers at Siemens Healthineers an idea: They wondered how it was possible for Gollum to look so strikingly real alongside human actors despite having been inserted into the scenes after they were filmed. The answer was a technique known as “image-based lighting calculation,” and a team of researchers led by Klaus Engel at Siemens Healthineers used this know-how from the animation film industry to develop their own cinematic rendering technology. Based on medical imaging data, the technique generates photorealistic images of the inside of the body using complex algorithms that model bones, organs, skin, and blood as well as simulating natural lighting.
Cinematic rendering is revolutionizing medical education and patient communication. This kind of virtual journey through the body visualizes human anatomy in a way that is both true to life and understandable. That also makes it easier to diagnose certain diseases and to plan surgery. The rendered images are so vivid that they can give the surgeon a highly detailed picture of the specific anatomical structures that will be found in the patient during the operation.
2020: The real world and virtual reality are merging into one another thanks to the coming together of two technologies: cinematic rendering and Microsoft HoloLens 2. This allows physicians to hold a patient’s heart, for example, in their hands in the form of a 3D projection. At a time when people were still tinkering about with stereoscopes, this would probably have been dismissed as utopian thinking.