Trailer-based scanners that can move between hospitals have proved to be an effective way of broadening access to imaging services. Several European countries have invested heavily in this concept of mobile modalities, including Germany, Italy, and the U.K. Now residents in the most mountainous regions of Switzerland look set to benefit from a new mobile PET/CT scheme.
Although Switzerland is a relatively small country, providing population-wide PET/CT is still problematic, according to Prof. Osman Ratib, head of nuclear medicine at the University Hospital of Geneva. Few hospitals can justify investing in PET/CT, given the high cost of purchase, maintenance, and regular upgrades. Patient referral rates are also so low in many areas that scanners would be standing idle for long periods.
The result is that Switzerland's PET/CT base is concentrated in just a few large university hospitals in major cities. Individuals living in less-populated towns and villages face a lengthy trip along mountain roads to reach these locations.
"The evidence base showing that we need PET/CT for the staging of cancers is growing," Ratib said during a session on regional PACS and telemedicine at the Computer Assisted Radiology and Surgery congress held in Barcelona in June. "All patients should have equality of care, but here in Switzerland, accessing that is logistically difficult. It is a matter of getting there."
The mobile PET/CT unit now in operation in Switzerland has been purchased by the University Hospital of Geneva. It is available to be rented out by public and private hospitals on a fee-per-study basis. Study costs, which are regulated by Swiss insurers, typically range from 1200 SFr (EUR735) to 2000 SFr (EUR1230) depending on the type of examination and the need for CT contrast.
The trailer is divided into three separate sections: an examination room, a room for radioisotope preparation and injection, and the scanner control room. Adherence to strict national regulations on lead shielding means that the trailer is the heaviest mobile imaging unit in Europe.
The University Hospital of Geneva provides trained technicians to operate the PET/CT scanner according to validated protocols and supplies radioisotopes generated from its own cyclotron. A teleradiology system has been set up so that radiologists and nuclear medicine physicians back in Geneva can either report the images themselves or provide added expertise in difficult cases. Training is being given to help local medical staff become more self-sufficient.
"We have a lot of expertise in PET/CT in Geneva; we have three PET/CT units," Ratib said. "We can provide remote interpretation, but we believe that as the system gets used, local radiologists and nuclear medicine physicians will learn how to do the work and they will not need us anymore."
The teleradiology system is based around OsiriX Open Source software, which was developed at the University of Geneva. The software supports 3D and 4D viewing as well as PET/CT fusion.
Images are sent directly from the scanner to the OsiriX workstation on the trailer. From there, they can be burned onto a CD or transmitted securely over the Internet to another OsiriX workstation.
Because OsiriX is built on a Macintosh platform, users also benefit from Apple's built-in iChat videoconferencing functionality. This IP-based method of two-way real-time communication and image sharing may be especially useful for hospitals that do not have a PACS.
"This is one of the best IP-based videoconferencing facilities, in terms of quality. Even on DSL lines, the videostream of the full screen is pretty good," he said. "It can be used on laptops and will soon be available on iPhones as well."
Plans to use wireless communication are being considered. At present, the PET/CT must be physically connected to each hospital's local network. A wireless system has been tested but not yet implemented clinically.
--By Paula Gould