Imaging Breast Cancers using Radial Modulation Imaging, A New Ultrasound Contrast Imaging Technique Hamid H. Shariff (M.Sc Candidate), Peter D. Bevan, Raffi Karshafian and Peter N. Burns Department of Medical Biophysics, University of Toronto, Toronto, Canada Imaging Research, Sunnybrook and Women’s Collage Health Sciences Centre, Toronto, Canada Contact: hshariff@swri.ca Mammography is now established as a gold standard in screening and diagnosis of breast cancers and use ionizing x-rays. Exposing women’s breast to ionizing radiation may induce breast carcinomas that may appear in later years of their lives 1-6 . Ultrasound imaging of breast is a non invasive and uses no ionizing radiation. Angiogenesis is a key element in the progression of solid cancer. It describes the formation of new blood vessels, which provide the blood containing oxygen and nutrients to the tumor 7-9 . Detecting contrast agents where there is low blood flow such as in angiogenesis is challenging. Pulse inversion 10 and other current contrast imaging techniques for ultrasound rely on same frequency to induce bubble resonance and to form the image, because these resonant frequencies lie between (2-4MHz), the resulting ultrasound images lack the spatial resolution needed to detect microbubbles in small blood vessels typically associated with angiogenesis in a superficial cancer. The principle of “Radial Modulation Imaging” 11-12 a bubble driven by ultrasound below its resonance will oscillate out of phase with one driven above its resonance 13 . Our in-vitro experiments with two-transducer model have shown the feasibility 11 of this method and gave excellent contrast-to-clutter enhancement of 35dB and results showed extreme sensitivity to phase. When implemented by Doppler processing ‘Radial Modulation Doppler’ will make imaging human microcirculation a reality. Radial modulation offers a means of decoupling the imaging and excitation frequencies in contrast imaging for ultrasound, and hence a potential method for high frequency, high-resolution contrast imaging using currently available contrast agents. This may revolutionize the detection and diagnosis of breast cancers using ultrasound. References: [1] Beckett J et al. Analysis of Benefit: risk ratio and mortality reduction for the UK Breast Screening Programme. Br J Radiol 2003;76; 309-20 [2] Law J. Cancers detected and induced in mammographic screening: new screening schedules and younger women with family history. Br J Radiol 1997;70:62–9. [3] Mettler F et al . Benefits Versus Risks From Mammography: A Critical Assessment. Cancer 1996:77:903-9 [4] Mettler F et al . Benefits Versus Risks From Mammography: A Critical Assessment. Obstetrical and Gynecology survey 1996:51(6) 352-3 [5] Law J. Variations in individual radiation dose in a breast-screening programme and consequences for the balance between associated risk and benefit. Br J Radiol 1993;66:691–8. [6] Feig SA, Ehrlich SM. Estimation of radiation risk from screening mammography: recent trends and comparison with expected benefits. Radiology 1990;174:638–47. [7] Folkman J, Merler E, Abernathy C, Williams G. Isolation of a tumor factor responsible or angiogenesis. J Exp Med 1971;133:275-88. [8] Hanahan D, Folkman J. Patterns and emerging mechanisms of the angiogenic switch during tumorigenesis. Cell 1996; 86:353-64. [9] Folkman J. Incipient angiogenesis. Journal of the National Cancer Institute 2000;92:94-5. [10] Hope Simpson D, Chin CT, Burns PN. Pulse Inversion Doppler: A new method for detecting nonlinear echoes from microbubble contrast agents. IEEE Transactions, UFFC 1999; 46:372-382 [11] Shariff H, Bevan P, Karshafian R, Karakolis M, Banerjee M and Burns P, “Radial Modulation Imaging: A dual frequency ultrasound imaging technique for microbubble contrast”. 11 th European Symposium on Ultrasound Contrast Imaging. Book of Abstracts P64-66 Rotterdam: Erasmus Univ, 2006 [12] Shariff H, Bevan P, Karshafian R, Hudson J and Burns P, “Imaging Tumour Blood Flow using Radial Modulation Imaging, A New Ultrasound Contrast Imaging Technique”Ontario Center of Excellence for Breast Cancer Imaging Research(INO),Toronto,April-2006, Book of Abstracts (in press). [13] Hansen R, Johansen TF, Burns PN, Angelsen BAJ. Contrast Agent Detection through Low Frequency Manipulation of High Frequency Scattering Properties. IEEE UFFC Ultrasonics Symposium. Montreal, 2004 [14] Hansen R, Angelsen B, Burns PN,Bouakaz A, Borsboom J, Versluis M, deJong N,. “Radial modulation imaging”. In: tenCate F, deJong N, eds. 10 th European Symposium on Ultrasound Contrast Imaging. Book of Abstracts. P90-92 Rotterdam: Erasmus Univ, 2005. Acknowledgement: This work is supported by, the Terry Fox Programme of National Cancer Institute of Canada, Canadian Institute of Health Research and ORDCF