国際医工学セミナー
千葉大学国際医工学セミナー
International Seminar Series on Biomedical Engineering
第8回
日時：2010年12月10日（金） 17:00 -
場所：千葉大学ＣＦＭＥ Ｂ号棟１階会議室 （西千葉キャンパス）
講演者
Prof. Ananda Mohan
University of Technology Sydney
タイトル
Microwave Imaging for Biomedical Applications
概要
Microwave Imaging is a non-intrusive imaging modality that uses the non-ionising microwave radiation. It can detect the energy scattered, reflected or transmitting through an object when illuminated by an incident microwave signal. The backscattered fields can reveal useful information about the object, both internal and external, such as the dielectric properties of the object as well as its shape. Hence, the use of microwave imaging is becoming more prevalent for biomedical applications as well as for the detection of interior hidden defects in manufactured and packaged materials. My talk mainly concentrates on the use of microwave imaging for medical applications.
Microwave imaging of lossy dielectric objects has proven to be of great interest for many bio-medical applications as it can be useful for examining the human physiology, such as for the application in the early stage breast cancer detection. Breast cancer is the most common cancer in women and second leading cause of female mortality. Currently ultrasound and X-ray mammography are widely used to detect breast cancer; however they suffer from relatively high missed- and false-detection rates and involve uncomfortable compression of the breast. X-rays are also ionising and therefore not generally suited for frequent screening.
Breast cancer detection using microwave imaging techniques has attracted many research groups for the last several decades, due to its potential to become a very useful complementary imaging modality. The current active microwave imaging techniques have two main streams: microwave tomography and radar microwave imaging. Microwave tomography reconstructs the images of dielectric properties throughout the whole breast by solving an inverse scattering problem. Radar microwave imaging only focuses on significant scatterer such as malignant tissues. It does not need to solve the complex nonlinear and ill-posed inverse scattering problem as in tomography. The physical basis for the radar technique is the tissue-dependent microwave scattering and selective absorption within the breast. It employs low-power microwave signals to be transmitted into the breast using an array of antennas which inturn also collect the backscattered microwave signals. The backscattered signals are used in image reconstruction by comparing the energy at each potential location within the breast so as to indicate the tumour location. However, the recent reports from surgeries revealed that the dielectric contrast between malignant tissue and normal breast tissue could be very close which severely limits the use of pure energy based approaches. Further, the malignant tissue response may be severely interfered by the surrounding fibro connective or glandular breast tissues.
During the talk, I will discuss on our current research on the discrimination of malignant and benign or normal breast tissues using microwave imaging by our group at the University of Technology, Sydney (UTS), Australia.