25 Mars – Thesis defense - Quentin Cassar

10 h Amphi Jean-Paul Dom - laboratory IMS / building A31 (Talence campus)

Terahertz imaging and spectroscopy for breast cancer detection.

The failure to accurately delineate breast tumor margins during breast conserving surgeries results in a 20% re-excision rate. Consequently, there is a clear need for an operating room device that can precisely define  intraoperatively breast tumor margins in a simple, fast, and inexpensive manner. This manuscript reports investigations that were conducted towards the ability of terahertz radiations to recognize breast malignant lesions among freshly excised breast volumes. Preliminary works on terahertz far-field spectroscopy have highlighted the existence of a contrast between healthy fibrous tissues and breast tumors by about 8% in refractive index over a spectral window spanning from 300 GHz to 1 THz. The origin for contrast was explored. Results seem to indicate that the dynamics of quasi-free water molecules may be a key factor for demarcation. On these basis, different methods for tissue segmentation based on refractive index map were investigated. A cancer sensitivity of 80% was reported while preserving a specificity of 82%. Eventually, these pilot studies have guided the design of a BiCMOS-compatible near-field resonator-based imager operating at 560 GHz and sensitive to permittivity changes over breast tissue surface.

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