Distributed nuclear medicine applications using World Wide Web and Java technology

Web-Based Technology for Remote Viewing of Radiological Images: App Validation

BACKGROUND

Internet technologies can create advanced and rich web-based apps that allow radiologists to easily access teleradiology systems and remotely view medical images. However, each technology has its own drawbacks. It is difficult to balance the advantages and disadvantages of these internet technologies and identify an optimal solution for the development of medical imaging apps.

OBJECTIVE

This study aimed to compare different internet platform technologies for remotely viewing radiological images and analyze their advantages and disadvantages.

METHODS

Oracle Java, Adobe Flash, and HTML5 were each used to develop a comprehensive web-based medical imaging app that connected to a medical image server and provided several required functions for radiological interpretation (eg, navigation, magnification, windowing, and fly-through). Java-, Flash-, and HTML5-based medical imaging apps were tested on different operating systems over a local area network and a wide area network. Three computed tomography colonography data sets and 2 ordinary personal computers were used in the experiment.

RESULTS

The experimental results demonstrated that Java-, Flash-, and HTML5-based apps had the ability to provide real-time 2D functions. However, for 3D, performances differed between the 3 apps. The Java-based app had the highest frame rate of volume rendering. However, it required the longest time for surface rendering and failed to run surface rendering in macOS. The HTML5-based app had the fastest surface rendering and the highest speed for fly-through without platform dependence. Volume rendering, surface rendering, and fly-through performances of the Flash-based app were significantly worse than those of the other 2 apps.

CONCLUSIONS

Oracle Java, Adobe Flash, and HTML5 have individual strengths in the development of remote access medical imaging apps. However, HTML5 is a promising technology for remote viewing of radiological images and can provide excellent performance without requiring any plug-ins.

An Evaluation of HTML5 and WebGL for Medical Imaging Applications

Despite the fact that a large number of web applications are used in the medical community, there are still certain technological challenges that need to be addressed, for example, browser plug-ins and efficient 3D visualization. These problems make it necessary for a specific browser plug-in to be preinstalled on the client side when launching applications. Otherwise, the applications fail to run due to the lack of the required software. This paper presents the latest techniques in hypertext markup language 5 (HTML5) and web graphics library (WebGL) for solving these problems and an evaluation of the suitability of the combination of HTML5 and WebGL for the development of web-based medical imaging applications. In this study, a comprehensive medical imaging application was developed using HTML5 and WebGL. This application connects to the medical image server, runs on a standard personal computer (PC), and is easily accessible via a standard web browser. The several functions required for radiological interpretation were implemented, for example, navigation, magnification, windowing, and fly-through. The HTML5-based medical imaging application was tested on major browsers and different operating systems over a local area network (LAN) and a wide area network (WAN). The experimental results revealed that this application successfully performed two-dimensional (2D) and three-dimensional (3D) functions on different PCs over the LAN and WAN. Moreover, it demonstrated an excellent performance for remote access users, especially over a short time period for 3D visualization and a real-time fly-through navigation. The results of the study demonstrate that HTML5 and WebGL combination is suitable for the development of medical imaging applications. Moreover, the advantages and limitations of these technologies are discussed in this paper.

Systems for remote interpretation of emergency studies

Telenuclear medicine facilitates a timely expert interpretation of emergency nuclear medicine studies. Current, high-speed Internet connection allows nuclear medicine physicians to be on-call from their homes. Software to support telenuclear medicine is becoming more widely available, although the design of some departments makes implementation difficult. Quality control of the remote monitor requires special attention to ensure correct interpretation. Fortunately, monitor quality control can be performed quickly using relatively simple procedures. Thus, expert interpretation of emergency nuclear medicine studies is practical.

Performance of Web-based image distribution: server-oriented measurements

The aim of this study was to assess the performance of Web-based image distribution when multiple personal computers (PCs) are downloading images simultaneously for different server hardware configurations. Using specially developed software, the time-to-display (TTD) of different image types was measured with up to 16 concurrent PCs for various combinations of processor, random access memory (RAM), network connection and image compression. The TTD increased linearly with the number of concurrent PCs but remained under 5 s in most of the cases, even with 16 concurrent PCs. Only with a 10-Mbit/s network connection or with lossy compression were TTDs above 5 s obtained. Two processors instead of one led to a slight and constant improvement of the TTD. Reducing the amount of RAM increased the TTD mainly for computed radiography (CR) images. There was no difference between a 200- and 100-Mbit/s network, but 10 Mbit/s proved significantly worse. When increasing the number of clients lossless compression performed substantially better than lossy. A standard off-the-shelf server provides an appropriate download performance even with 16 concurrent clients. Processor speed and RAM amount are of minor importance, but it is highly recommended to use a 100-Mbit/s network connection and to avoid the application of on-demand lossy compression in a local area network.

Performance of Web-based image distribution: client-oriented measurements

The aim of this study was to define a clinically suitable personal computer (PC) configuration for Web-based image distribution and to assess the influence of different hard- and software configurations on the performance. Through specially developed software the time-to-display (TTD) for various PC configurations was measured. Different processor speeds, random access memory (RAM), screen resolutions, graphic adapters, network speeds, operating systems and examination types (computed radiography, CT, MRI) were evaluated, providing more than half a million measurements. Processor speed was the most relevant factor for the TTD; doubling the speed halved the TTD. Under processor speeds of 350 MHz, TTD mostly remained above 5 s for 1 CR or 16 CT images. Here Windows NT with lossy compression were superior. Processor speeds of 350 MHz and over delivered TTD <5 s. In this case Windows 2000 and lossless compression were preferable. Screen resolutions above 1280 x 1024 pixels increased the TTD mainly for CR images. The RAM amount, network speed and graphic adapter did not have a significant influence. The minimum threshold for clinical routine is any standard off-the-shelf PC better than Pentium II 350 MHz, 128 MB RAM; hence, high-end PC hardware is not required.

Platform-independent image reconstruction for spiral magnetic resonance imaging

The distinct feature of data acquisition for magnetic resonance imaging (MRI) is that the data are sampled in frequency domain instead of spatial domain. Therefore, the acquired data must be inverse Fourier transformed to generate images. To apply fast Fourier transform (FFT), the data are usually acquired on rectilinear grids. However, acquiring data on rectilinear grids is not very efficient in MRI. A spiral trajectory, which starts at the origin of the frequency domain and spins out to higher spatial frequency is more efficient and faster than the conventional method. Since the spiral trajectories do not sample on rectilinear grids, raw data must be re-interpolated onto rectilinear grids prior to inverse FFT. This re-gridding process is done using a reconstruction program. When the platforms to run the program grow, the efforts required to maintain the program become prohibitive. This problem can be solved through the platform-independent Java programming language. In this paper, we report on our attempt to implement the spiral MRI reconstruction program in Java. We show that the performance is not significantly affected and that it is practical to use a platform-independent reconstruction software.