Neuroblastoma is the most common extra-cranial, solid, malignant tumor in children. Advances in radiology have made possible the detection and staging of the disease. However, there is no method available at present that can go beyond detection and qualitative analysis, toward quantitative assessment of the tissue composition of the primary tumor mass.

Tumor definition and diagnosis require the analysis of the spatial distribution and Hounsfield Unit (HU) values of voxels in computed tomography (CT) images, coupled with knowledge of the normal anatomy. Segmentation of the tumor in neuroblastoma is complicated by the fact that the mass is heterogeneous in nature; furthermore, viable tumor, necrosis, fibrosis, and normal tissue are often intermixed. We propose several strategies to improve tumor segmentation. In our scheme, the normal structures expected in abdominal CT images are delineated and removed from further consideration; the remaining parts of the image volume are then examined for the tumor mass. Mathematical morphology, the Hough transform, fuzzy connectivity, region growing, active contour models, and other image processing tools are employed for this purpose. Expert knowledge provided by the radiologist in the form of the expected structures and their shapes, HU values, and radiological characteristics are also incorporated into the segmentation algorithm.

We also propose a methodology for the estimation of the tissue content of the tumor mass that includes a Gaussian mixture model to estimate the tissue composition of the primary tumor. Results indicate that the proposed technique should be useful in assessing the response to therapy and in the planning of delayed surgery for resection of the tumor in patients with neuroblastoma. Quantitative analysis could provide important information and serve as a decision-support tool to radiologist and oncologists, and result in better treatment of the disease.

Rangaraj (Raj) Mandayam Rangayyan was born in Mysore, Karnataka, India, on 21 July, 1955. He received the Bachelor of Engineering degree in Electronics and Communication in 1976 from the University of Mysore at the People's Education Society College of Engineering, Mandya, Karnataka, India, and the Ph.D. degree in Electrical Engineering from the Indian Institute of Science, Bangalore, Karnataka, India, in 1980. He was with the University of Manitoba, Winnipeg, Manitoba, Canada, from 1981 to 1984.

He is at present a Professor with the Department of Electrical and Computer Engineering, and an Adjunct Professor of Surgery and Radiology, at the University of Calgary, Calgary, Alberta, Canada. His research interests are in the areas of digital signal and image processing, biomedical signal analysis, medical imaging and image analysis, pattern recognition and analysis, and computer vision. He has lectured extensively in many countries, including India, Canada, U.S.A., Brazil, Argentina, Uruguay, Chile, U.K., The Netherlands, France, Spain, Italy, Finland, Russia, Romania, Egypt, Malaysia, Thailand, China, and Japan. He has collaborated with many research groups in Brazil, U.K., Spain, France, and Romania.

He was an Associate Editor of the IEEE Transactions on Biomedical Engineering from 1989 to 1996; the Program Chair and Editor of the Proceedings of the IEEE Western Canada Exhibition and Conference on "Telecommunication for Health Care: Telemetry, Teleradiology, and Telemedicine", July 1990, Calgary, Alberta, Canada; the Canadian Regional Representative to the Administrative Committee of the IEEE Engineering in Medicine and Biology Society (EMBS), 1990-93; a Member of the Scientific Program Committee and Editorial Board, International Symposium on Computerized Tomography, Novosibirsk, Russia, August 1993; the Program Chair and Co-Editor of the Proceedings of the 15th Annual International Conference of the IEEE EMBS, October 1993, San Diego, CA; Program Co-Chair, 20th Annual International Conference of the IEEE EMBS, Hong Kong, October 1998; and Co-Chair and Co-Editor, IASTED International Conference on Telehealth, Banff, AB, 2005.

His research productivity was recognized with the 1997 and 2001 Research Excellence Awards of the Department of Electrical and Computer Engineering, the 1997 Research Award of the Faculty of Engineering, and by appointment as a "University Professor" in 2003, at the University of Calgary. He was awarded the Killam Resident Fellowship in 1998 and 2002 by the University of Calgary in support of writing two books: Biomedical Signal Analysis (516 pages, IEEE/ Wiley, 2002) and Biomedical Image Analysis (1,306 pages, CRC, 2005). He was recognized by the IEEE with the award of the Third Millennium Medal in 2000, and was elected as a Fellow of the IEEE in 2001, Fellow of the Engineering Institute of Canada in 2002, Fellow of the American Institute for Medical and Biological Engineering in 2003, and Fellow of SPIE: the International Society for Optical Engineering in 2003.