Terahertz imaging applied to cancer diagnosis

Abstract

We report on terahertz (THz) time-domain spectroscopy imaging of 10 microm thick histological sections. The sections are prepared according to standard pathological procedures and deposited on a quartz window for measurements in reflection geometry. Simultaneous acquisition of visible images enables registration of THz images and thus the use of digital pathology tools to investigate the links between the underlying cellular structure and specific THz information. An analytic model taking into account the polarization of the THz beam, its incidence angle, the beam shift between the reference and sample pulses as well as multiple reflections within the sample is employed to determine the frequency-dependent complex refractive index. Spectral images are produced through segmentation of the extracted refractive index data using clustering methods. Comparisons of visible and THz images demonstrate spectral differences not only between tumor and healthy tissues but also within tumors. Further visualization using principal component analysis suggests different mechanisms as to the origin of image contrast.

Application of automatic statistical post-processing method for analysis of ultrasonic and digital dermatoscopy images

“…Nowadays, many segmentation methods which could be split into different categories are widely used, for example: thresholding approaches, region-growing and region-merging approaches [24], classifiers, clustering approaches, Markov random field models, ANNs, deformable models [25,26], atlas-guided approaches [27], quadric functions with the implementation in order to avoid confusing between shadows and pigmented skin lesions [28], THz spectroscopic imaging and clustering algorithms [29], texture and fractal analysis [30,31], watershed technique [32], gradient vector flow algorithms [33] coherent analysis [34], melanoma recognition system method based on the ABCD criteria [35], support vector machines [36]. In addition to image segmentation tools as active contours and snakes, edge detection and clustering techniques based on thresholding were used [37].…”

Infrared and terahertz in biomedicine

“…Examples of diagnosis of cancerous tissues with THz radiation are reported as they exhibit different hydration levels from normal tissues [69,70].…”

Photomechanical meta-molecule array for real-time terahertz imaging

“…A variety of commonly used packaging materials, such as paper, fabrics and plastic, are transparent to THz waves; this technology may thus have potential in the security field and non-destructive inspections 4,5 . The low photon energy of THz radiation causes no ionization risk, and the THz fingerprint spectra for biomolecules may allow THz imaging to be used as a tool for medical diagnoses and analyses, especially for skin burns and skin cancers 6,7 . Accordingly, continuous efforts have resulted in the development of high-sensitive and real-time THz detectors for use as the key component in THz imaging systems 8 .…”