vice versa, hospitals transmit digital information about patients, saving transport, time, and money.
Physicians' use of telemedicine systems varies according to medical specialty. For example, radiologists, currently the
main users of telemedicine technology, distribute digitized images and interpret them either on radiological workstations or, more conventionally, by printing the digital images to film. The radiologist's report is then returned to the originating physician via fax or e-mail, or the film might be discussed in a videoconferencing session.
Telemedicine projects are not restricted to radiology; systems are now operating in the fields of psychiatry, pathology, orthopedics, dermatology, accident and emergency medicine, and other disciplines. Such telemedicine applications have to cope with many technical challenges, three of which are listed below.
Data volumes.
Medical images must be rendered at high resolutions to retain diagnostic quality. The American College of Radiology recommends approximately 2048 by 2048 pixels at 12-bit gray-scale for primary diagnostic reading and 4096 by 4096 pixels (with the same contrast depth) for mammography.
Retrieval speed.
Busy
medical-staff members cannot wait for massive images to be loaded over slow networks. This means high-bandwidth networks and fast transaction speeds in image retrieval have to be achieved.
Intuitive user interfaces.
Users often are not computer-literate; thus, systems have to be easy to understand and operate.
Medical engineers construct telemedicine systems using off-the-shelf hardware and software. Some applications need very high-resolution display and image-capturing equipment; fortunately, the current multimedia boom means the prices of sophisticated imaging boards are falling.
Interoperational standards for system integration are crucial to ensure that standard computer equipment can access medical devices. Direct image capturing from computerized tomography (CT) or magnetic resonance imaging (MRI) scanners and the distribution of images from laboratories to physicians are made far easier through a common exchange format.
Additionally, images should include, at th
e very least, the patient's name, age, sex, current problem, and medical history for identification. That's also an issue of standardization. But telemedicine proponents expect the emerging Digital Imag-ing and Communications in Medicine (DICOM; see the sidebar
"Image Standards"
) standard to replace the proprietary nature of many of today's medical-image data-exchange systems.
These standards will aid image acquisition, but they represent only the start. Clinical data must then be routed to the right place, which is
sometimes miles away
. Here, wide-area networking capability is crucial for the system to work with the multitude of international telecommunications systems.
Telemedicine requires networks that are not restricted to urban areas. A good example of what a high-speed telemedicine network could look like is Telecom Finland's implementation of a telemedicine framework on its nationwide broadband asynchronous-transfer-mode (ATM) network. It enables high-resolut
ion videoconferencing and allows radiological images to be selected from remote databases.
The national ATM backbone links Finland's universities and hospitals and provides access to specialist expertise on demand. For example, during a recent technology demonstration, a liver ultrasound was conducted in a hospital in Lapland and transmitted in real time to a lecture theater in Helsinki, located 1000 km away.
Some experts argue that there's little point in relying on technologies that demand high-bandwidth ATM, because most areas that need telemedicine are poorly served by advanced telecommunications services. In this respect, they say, the Finnish ATM infrastructure is an exception to the rule.
Most people who have attempted to implement telemedicine applications internationally say that good systems should be designed independently of telecommunications methods. Simple "store-and-forward" systems, which send CT or MRI images overnight via plain old telephone service (POTS) lines, are often
the most cost-effective solution. The subsequent reports can then be either faxed or e-mailed back the next day. In the U.S., approximately 12,000 computer-based teleradiology installations, and over 95 percent of all reimbursed telemedical services, are based on the store-and-forward model.
The costs in telemedicine can be broken down into three parts: technology (i.e., hardware and software), staff/maintenance, and telecommunications. Technology and staff/maintenance costs have to be split between "send" and "receive" stations. This is an important point. Unless these systems are properly managed on both sides, any benefit they may be able to provide will be lost.
The biggest variable in this calculation -- apart from professional medical fees -- is telecommunications costs. The cost of international transmission of a series of X rays can add between $10 and $60 to the total consultation costs. This cost may seem high; however, the increasing competition on the telecommunications market will so
on reduce communications costs for such large-scale users as hospitals.
Where to Find
DeTeBerkom
Berlin, Germany
Phone: +49 30 46701 314
Fax: +49 30 46701 444
E-Mail:
pr@deteberkom.de
Telecom Finland
Rovaniemi, Finland
Phone: +358 20 40 79 470
Fax: +358 40 84 32 043
E-Mail:
antero.rahtu@tele.telebox.fi
UKRV
Berlin, Germany
Phone: +49 30 45070022
Fax: +49 30 45070907
E-Mail:
lutz@ukrv.de
Internet:
http://www.ukrv.de/komet
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