Development of technology, products and services
For most radiologists, the day is filled with interpreting images, and the interpretation will often take place in another location than where the images were made. Back when the images were made on photographic film, the interpretation would most often be undertaken in proximity to the image-generating modalities – on lightboxes in separate study rooms. In principle, the interpretation could be undertaken anywhere, as long as the images and the clinical issues were available to the radiologist. This is what forms the basis of teleradiology. As a rule, the development of new services grows from new technological opportunities. For example, the first attempts at teleradiology were made approximately at the same time as the moon landing in 1969. If live images could be transferred from the moon to people’s homes, it would surely be possible to transfer x-ray images to the other side of town. The same technology was consequently put to use, and we had the first examples of teleradiology (1). The images were transferred in the same way as TV programmes – a TV camera at one end shot the x-ray image, a TV screen displayed them at the other end, and the two were connected by a communication satellite. The images were interpreted in real time. The quality was deemed to be acceptable (2), but the benefits were probably not quite proportional to the cost – satellite transfer was and remains costly.
Ten years later, technology for transferring data through telephone lines had become available, and a standard x-ray image could be transferred in four minutes at the rate of a local phone call (3). Interpretation was still undertaken in real time, the camera was placed in front of the x-ray film while the image was transferred over the telephone line. Even though the costs of transfer decreased and the quality and detail of the image increased, this model also proved to be less than appropriate for more comprehensive radiological activities. Managing the real-time transfer and interpretation of images via TV technology was complicated, and in spite of the progress made, the quality remained far from optimal. It was still easier and cheaper to move the radiologist than to move the images.
The next step of the development was digitalisation of the images, so that they could be stored and forwarded, and transfer could thus be separated from interpretation (4). However, it was the combination of systems for digitalisation of images, systems for storing and communicating images (Picture Archiving and Communication Systems, PACS) and cheaper and better communication technologies that turned teleradiology into an interesting option for a larger audience (5).
The Nordic countries were at the forefront. Large distances and sparsely populated areas made teleradiology interesting, and advanced technical competence made it possible. The pioneering efforts of Jan Størmer, radiologist and Senior Consultant at the University Hospital of North Norway, should be emphasised in particular. As early as in 1992, x-ray images were transferred from Tromsø Military Hospital to the then Tromsø Regional Hospital (6). Instead of having assistance from a radiologist once a week, images could be interpreted by a radiologist every day. In 1995, digital recording of images was introduced (7), and the service had thus become fully digital.
From the mid-1990s onwards the technology improved in terms of speed, quality and cost. Portability has been further improved (8), but the technological principles for teleradiological image transfer remain the same. On the other hand, we have seen the emergence of new teleradiological services. In the US, companies such as NightHawk, vRad and a dozen others have delivered commercial interpretation services since the 1990s. In Europe, a few companies have emerged with the intention of offering services for the European market, and even in Norway private actors may supply teleradiological services, even though they primarily use the technology to distribute the workload among their own departments.
In 2009, an estimated 50 – 55 % of all American hospitals used some form of internal or external teleradiological services (9). In 2010, one-third of all Norwegian hospitals reported to the teleradiological committee of the Norwegian Radiological Association that they were using teleradiology for primary interpretation (10, 11).