A mobile ultrasound system has been developed, which makes ultrasound examinations possible in harsh environments without reliable power sources, such as ambulances, helicopters, war zones, and disaster sites. The goal of this project was to analyze three different wireless communication technologies that could be integrated into the ultrasound system for possible utilization in remote data applications where medical information may be transmitted from the mobile unit to some centralized base station, such as an emergency room or field hospital. By incorporating wireless telecommunication technology into the design, on site medical personnel can be assisted in diagnostic decisions by remote medical experts.
The wireless options that have been tested include the IEEE 802.11g standard, mobile broadband cards on a 3G cellular network, and a mobile satellite terminal. Each technology was tested in two phases. In the first phase, a client/server application was developed to measure and record general information about the quality of each link. Four different types of tests were developed to measure channel properties such as data rate, latency, inter-arrival jitter, and packet loss using various signal strengths, packet sizes, network protocols, and traffic loads. In the second phase of testing, the H.264 Scalable Video Codec (SVC) was used to transmit real-time ultrasound video streams over each of the wireless links to observe the image quality as well as the diagnostic value of the received video stream.
The information gathered during both testing phases revealed the abilities and limitations of the different wireless technologies. The results from the performance testing will be valuable in the future for those trying to develop network applications for telemedicine procedures over these wireless telecommunication options. Additionally, the testing demonstrated that the system is currently capable of using H.264 SVC compression to transmit VGA II quality ultrasound video at 30 frames per second (fps) over 802.11g while QVGA resolution at frame rates between 10 and 15 fps is possible over 3G and satellite networks.