Introduction:
Most medical devices are either implanted within human bodies or work in the proximity of human bodies. During the operation of these devices, electric signals will interact with surrounding human bodies as well as other near by electronic systems. Due to such interactions, these medical devices may also cause health concerns. For example, when medical telemetry systems transmit information back to hospital, just like typical mobile phone operations, some of the electromagnetic energies can be deposited into nearby human subjects. If the deposited energy exceeds a certain limit, it leads to many health concerns, such as thermal damage and brain cancer.
While radio-frequency radiation from medical devices raises safety concerns in human subjects, external electronic systems could cause more serious medical consequence for patients with implantable medical devices. For example, when patients with medical implants undergo a magnetic resonance imaging (MRI) examination, the MRI system can completely damage the functionality of implanted devices. In addition, MRI system can cause significantly heating in tissues surrounding medical implants. Similar concerns were raised when patients with implantable devices pass through airport walk-through-metal-detectors (WTMD).
To ensure patient and public safety, the international electrotechnical commission (IEC) has developed a standard to limit the maximum energy deposition within human subjects under different environments. These standards set the limits for electromagnetic related quantifies, such electric field, magnetic field, induced electric current, and specific absorption rate2 (SAR), for the whole body, partial body, and local region within human subjects. However, these standards were developed based on very crude models and have not considered complexity of real human subjects. Carefully studies on how external electromagnetic stimulus internal nerve systems were not performed. In addition, for some applications, such as the SAR measurement near implantable devices, direct measurement of SAR values near the implantable devices are impossible. Due to these limitations, international-wise, there is no recommended procedure to evaluate these quantities

Significance: The market for medical implants is a global one. The world-wide orthopaedic surgery market is approximate 9 billions US $ per year with an annual growth rate of approximate 5%. The current market for cardiovascular implants alone is approximate 6.4 billion US $ and for active implants approximate 5.3 billion US $ [14]. Millions of people’s well-beings are affected by these devices. The proposed research work has significant impacts on both academic communities and industrial applications. Our interdisciplinary approach will open new areas of biomedical safety research and findings can be used in the future standard development in safety assessment. The success of this project will help to enhance the leading international position and to evaluate the reputation of the CUHK group in medical electronic safety assessment research and development. Most importantly, the research results will be used to guide the design of safe medical electronics.

Methodologies and Tasks: This project will be carried out via the completion of the following tasks:
(1) The creation of the world finest virtual electromagnetic human model, for bio-electromagnetics related researches, based on the 0.1 mm resolution virtual human model developed at CUHK. To develop the virtual EM human model, the current pixel based image model needs to be segmented into different organ objects so that the electromagnetic properties (i.e. complex permittivity) at different RF/microwave frequencies can be assigned to different tissues. This task requires a significant amount efforts from the researchers with medical background;
(2) Based on the virtual EM human model, a comprehensive multi-bio-physics simulation platform will be developed. The platform will incorporate electromagnetic and thermal modeling tools, which will help people to understand the biology effects on physiology parameters and to interpret the effects of nerve stimulus due to external electromagnetic emissions; and
(3) The exploration of a novel testing approach for medical device safety assessment. Since neither measurement nor modeling work alone can perform accurate safety assessment. The new approach will be able to predict the internal electromagnetic field strength based on the measurement data external to the human body and an efficient electromagnetic simulation.