2 Department of Medical Informatics, Kyushu University Hospital, 3-1-1 Maidashi, ... 7 Department of Surgery, Seoul National University Bundang Hospital, 300 ...
New technology Surg Endosc (2006) 20: 167–170 DOI: 10.1007/s00464-005-0282-7 Ó Springer Science+Business Media, Inc. 2005
International transmission of uncompressed endoscopic surgery images via superfast broadband Internet connections S. Shimizu,1 N. Nakashima,2 K. Okamura,3 J.-S. Hahm,4 Y.-W. Kim,5 B.-I. Moon,6 H.-S. Han,7 M. Tanaka1,8 1
Department of Endoscopic Diagnostics and Therapeutics, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan Department of Medical Informatics, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan Computing and Communications Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan 4 Department of Medicine, Hanyang University Medical College, #17, Haengdang-dong, Sungdong-ku, Seoul 133-792, Korea 5 Research Institute and Hospital, National Cancer Center, 809 Madu 1-dong, Ilsan-gu, Goyang, Gyeonggi 411-764, Korea 6 Department of Surgery, Ewha WomenÕs University, 911-1, Mokdong, Yangcheon-gu, Seoul 158-710, Korea 7 Department of Surgery, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Korea 8 Department of Surgery and Oncology, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan 2 3
Received: 18 April 2005/Accepted: 29 July 2005/Online publication: 7 December 2005
Abstract Background: Although telecommunication is increasing in popularity, poor-quality images sent through a narrowband network limit its use in the medical field. Methods: Kyushu University Hospital in Japan and four hospitals in Korea were linked via superfast broadband Internet connection. The digital video transfer system, which can transmit digital videos without loss of image quality, was used, and the bandwidth was 30 Mbps per line. Results: Of the 16 teleconferences conducted, 6 demonstrated real-time endoscopic surgery. In addition to the surgical images, preoperative diagnostic images, images of the operating room, and images of the staff in the conference room were transmitted to facilitate discussion. The network remained stable, and the sound delay was restricted to less than 0.3 s. In the other 10 teleconferences, recorded video images were used for discussion. Conclusions: The authors have established a high-quality, practical teleconference system that is economical and easy to use in clinical practice. This system shows promise for remote education beyond geographic borders. Key words: Broadband — Digital video transfer system — Endoscopic surgery — Internet — Telemedicine
Correspondence to: S. Shimizu
Endoscopic surgery has revolutionized the field of surgery as a whole. Because incisions are smaller than in open surgery, patients experience less pain and recover more quickly. However, specialized techniques and adequate experience are necessary for surgeons to perform endoscopic surgery in a safe and skillful manner. Therefore, attention is being paid to methods of education and training. Surgeons usually attempt to learn the advanced skills needed for endoscopic surgery by reading books or papers. These materials are useful, but there remains a need for surgeons to learn the procedures in practice. Edited videos are of limited value because they usually do not cover procedures in their entirety, and there is no opportunity to ask questions. Furthermore, it is not always feasible for doctors to visit leading institutions to see the advanced procedures. The best situation, therefore, is exposure to live surgery via telecommunication because it can be shown to many people at once and at any time. Although some tele-education systems for endoscopic surgery exist, they are not yet popular, mainly because the quality of the moving images is not adequate. The systems are useless or even misleading unless the audience can view the anatomy with its fine structures and fully follow the conversation without noise or time delay. With the existing telemedicine systems, it has been impossible to avoid compression of the images for transmission, which more or less degrades the image quality. However, a newly developed digital video transfer system (DVTS) has succeeded in sending the necessary information totally uncompressed, and therefore can provide medical-proof quality moving images [11]. A telecommunication system that can send
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surgical images as clear as those obtained in the operating room would no doubt be ideal for teaching endoscopic surgery. We report the establishment of a high-quality, high-speed telecommunication system based on a superfast broadband Internet connection between Korea and Japan, and we describe its first clinical application by which surgeons can simultaneously watch and discuss original-quality videos.
Table 1. Korea–Japan endoscopic surgery teleconferences Live demonstrations of surgery Laparoscopic cholecystectomy Laparoscopic distal gastrectomy Laparoscopic colectomy Teleconferences with recorded video images Laparoscopic cholecystectomy Laparoscopic distal gastrectomy Laparoscopic colectomy Laparoscopic hepatectomy Laparoscopic nephrectomy
6 1 4 1 10 1 4 2 1 2
Methods Network configuration Kyushu University Hospital in Fukuoka, Japan was connected to four hospitals in Seoul, Korea: Hanyang University Hospital, National Cancer Center, Ewha WomenÕs University Mokdong Hospital, and Seoul National University Bundang Hospital. The distance between Fukuoka and Seoul is about 600 km. We used three main networks to connect the hospitals. The first was the Kyushu GigaPOP (Point of Presence) Network (QGPOP) connecting Kyushu University Hospital and a local network operation center (NOC) in Fukuoka. The second was the Korea–Japan Cable Network (KJCN) connecting Fukuoka and Busan, and the third was the Korea Advanced Research Network (KOREN) connecting Busan and Seoul [14]. The KJCN is a submarine optic cable network that has a capacity of 2 Gbps. The bandwidth for the connection between Kyushu University Hospital and the first two hospitals in Korea was 1 Gbps, and that between Kyushu University Hospital and the last two was 155 Mbps.
Fig. 1. A conference room of Kyushu University Hospital in Japan. Images of the endoscopic surgery, operating room, and counterpart surgeon are seen separately.
System configuration We set up a teleconference system with bidirectional transmission over the network via Internet Protocol. The DVTS was used for sending and receiving both visual and audio signals. It is available as hardware (DV Stream, Fujitsu Co., Tokyo, Japan) or as software only, downloaded (http://www.sfc.wide.ad.jp/DVTS/software/win2000/setup0.0.1-1.exe) and installed on a personal computer (PCG-Z1/P, Sony Co., Tokyo, Japan). For real-time demonstration of endoscopic surgery, the operating room was connected to the conference room via two DVTS data streams. One was dedicated to transmission of the surgical images to preserve the image quality, and the other was for views of the operating room, preoperative images, or images of staff in the conference room, which could be selected by turning a switch. The two DVTS streams then were transmitted to a counterpart hospital. The endoscopic surgical image, produced at the interface of surgical instruments (EndoALPHA System, Olympus Medical System Co., Tokyo, Japan), was converted into Internet Protocol packets by the DVTS hardware. Meanwhile, images of operating room, images of the surgeonÕs manual manipulations, radiographic images, and images of the conference room were obtained by a digital video camera (DCRTRV50, Sony Co.) connected to the hardware DVTS via an IEEE1394 interface. For teleconferencing that involved digital video streams instead of live surgery, the surgical images were transmitted to the DTVS hardware through the IEEE1394 interface of the digital camcorder. The rate of transmission was 30 frames per second. The ethics committee of Kyushu University Faculty of Medicine formally approved this telemedicine project, and informed consent was obtained from each patient for transmission of the live surgery. Security software (C4-VPN, Focus Systems Co., Tokyo, Japan) was used during real-time transmission to protect each patientÕs privacy.
Measurement of network stability and time delay To determine network stability during the teleconferences, we set up a network traffic analyzer (Multi Router Traffic Grapher, http://people.ee.ethz.ch/oetiker/webtools/mrtg/) on a personal computer.
Network traffic was monitored at the conference roomÕs gateway to the Internet. For the measurement of time delay, the Watochi software (http:// rd.vector.co.jp/download/file/win95/personal/ff188144.html) was installed on a computer at the origin station. An image of the computer screen displaying the stopwatch software was obtained by video camera and sent to a remote station through the network. The image was sent directly back to the original station through the network. Thus, the two stopwatch images were seen simultaneously on the display at the origin station. The round-trip transmission time was determined by taking a photo of the original and returned stopwatch displays together at the origin station. The time delay was determined by dividing the time difference in half.
Results During the period February 2003 through January 2005, 31 international teleconferences were conducted via our newly established system. Of the 16 teleconferences that pertained to endoscopic surgery, 6 were real-time demonstrations of endoscopic surgery, and the remaining 10 were conducted with the use of recorded surgical videos The 16 endoscopic surgery teleconferences are listed in Table 1. The surgical procedures covered were laparoscopic cholecystectomy, gastrectomy, colectomy, hepatectomy, and renal transplantation. At a network station, three screens were set up: one for surgical streaming, one for pictures of the operating room or diagnostic images, and one for face-to-face discussion with the staff at the counterpart hospital (Fig. 1). The settings varied from a private clinical office to a large auditorium (Figs. 2 and 3).
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Fig. 2. A Korean station in a clinical office. Two monitors are set on a desk.
Fig. 3. A Korean station in an auditorium. Multiple images, including the surgical stream, chairman, audience, and surgical counterpart, are viewed on a large screen.
Stability of the network was maintained during a telesurgical conference with a bandwidth of 30 Mbps. The mean time delay ± standard deviation was 0.28 ± 0.13 s.
Discussion Telemedicine has been practiced for more than 30 years, but in the early stages, it was limited to the use of still images such as photographs and x-rays, or to simple moving images such as electrocardiograms and vital signs [4]. With the rapid development of information technology and network engineering in recent years and increased awareness of the usefulness and necessity of telecommunication in the field of endoscopic surgery, there have been many attempts to transmit moving images. It has been difficult, however, to achieve satisfactory levels of quality and speed due to the lack of adequate network bandwidth and an inability to preserve the original quality of images on the network.
The Integrated Services Digital Network (ISDN) has become the most widely used network system, and many authors have reported the extent of its usefulness [2, 6, 7, 10, 15]. However, its bandwidth is limited to 384 kbps even with three lines in use. Thus, the information volume that can be transmitted over the network is very small, approximately 1/100 that of DVTS. It was inevitable that a compression algorithm, such as H323, on the Picturetel videoconferencing system (Picturetel Corp. Danvers, MA) would be used to downsize the surgical images, but this more or less ruined the image quality [5]. Although Damore et al. [3] successfully used the Internet2 broadband network, they adopted a similar compression protocol and failed to take full advantage of the high-speed bandwidth. In 1999, when DVTS was invented in Japan, a new era for telemedicine was opened. As a tool by which digital video images can be transformed directly to an Internet protocol without compression of motion images, DVTS has many advantages over conventional image transmission systems [11]. It can perfectly preserve the quality of original moving images by avoiding compression processes. In addition, omission of these complex procedures can minimize the time latency between network stations. Encoding and decoding of pictures is time consuming. This system also allows the use of standard personal computers because there is no need to handle a complex algorithm. Furthermore, the system is very simple. The digital image can be transmitted directly through the IEEE1394 interface from the image source to a personal computer. We need only connect the output of a camcorder or surgical instruments to a personal computer with DVTS installed and with Internet access. Although we first used a hardware version of DVTS, the software is now freely downloadable from the Internet and works just fine. Additionally, in contrast to a television or satellite system, the Internet does not require any special license or large facility such as a television station or satellite antennas, so anyone can easily enjoy the high level of telecommunication at any time. Thus, our system is of high quality, but also is economical and user-friendly. There are several reports describing the use of this new technology in other situations [1, 9]. One situation involved the engineering field, in which remotely located users operated electric motors and conducted laboratory experiments via DVTS. It was possible for both sides to communicate smoothly, and for the remote users to observe close-up details of the motorsÕ fine movements [9]. Another situation involved the field of basic science, in which an electron microscope was remotely controlled, providing high-quality dynamic images of the specimen with low latency [1]. We are the first to apply DVTS to clinical medicine. In fact, endoscopic surgery is one of the best applications of telemedicine for several reasons. First, this surgical field is in a period of rapid development, and thus there are big differences in the levels of surgical skills among countries and hospitals. Second, surgical videos to be transmitted via network are
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always available in the regular clinical setting. Highquality moving images are mandatory for surgical training and consultation, and the prime advantage of the current system is its ability to transmit the same high-quality images obtained in the operating room to the other end of the network. Finally, the frame rate of 30 per second makes the image seamless, and the minimal latency of less than 0.3 s makes telecommunication quite enjoyable. There should be many possible applications for our system in addition to endoscopic surgery. Flexible endoscopy for gastrointestinal examinations is a candidate because new procedures are frequently introduced in this field, and moving images also are routinely available in clinics and quite useful for the development of therapeutic skills. Many people in this field are struggling to obtain better images on narrowband networks using compression protocols [8, 12, 16]. Teleproctoring of open surgery is another likely application if a camera system like the one reported by Rafiq et al. [13] is established to obtain good surgical pictures. Interventional radiology, cardiac catheterization, ultrasonography, and telepathology also are good candidates. Moreover, the telemanagement of patients and teleconsultation are feasible now that skin color and subtle changes in facial expressions can be visualized remotely by means of uncompressed moving pictures. In conclusion, we have developed a new international telecommunication system based on the superfast broadband Internet that can preserve the original quality of surgical images with minimal time delay. Because the Internet is economical and easy to access, we believe this system will facilitate the expansion of newly developed, less invasive surgery procedures effectively and beyond borders.
Acknowledgments. The authors truly appreciate the entire engineering staff of Hanyang University, the National Cancer Center, Korea University, Ewha WomenÕs University, Seoul National University Bundang Hospital, Korea Advanced Research Network, and Kyushu Infocom Company for their expertise in network preparation. This project was funded in part by the Core University Program of the Japan Society for the Promotion of Science and the Korea Science and Engineering Foundation, and by Kyushu University Interdisciplinary Programs in Education and Projects in Research Development.
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