Terahertz Endoscopy Through Laser-Driven Terahretz Sources And Detectors

https://techtransfer.universityofcalifornia.edu/NCD/29256.html

SUMMARY

UCLA researchers in the Department of Electrical Engineering have developed a miniaturized terahertz imaging system that can be integrated to the tip of commercially available endoscopes, with significantly larger detectable depths and faster image acquisition rates.

BACKGROUND

Terahertz imaging has found applications in medical diagnostics due to low interference, non-ionizing radiation, and high sensitivity and specificity to variations in tissue hydration levels. However, currently available terahertz imaging systems are limited by large size which hinders their application in medical imaging, limited penetration depth into the biological tissue (0.1mm), long acquisition time, and limited image resolution.

INNOVATION

UCLA researchers proposed a miniaturized terahertz imaging system that can be integrated to the tip of commercially available endoscopes, with significantly larger detectable depths and faster image acquisition rates. The proposed technology uses a two-dimensional array of plasmonic photoconductive terahertz sources and detectors and an image-processing algorithm to generate diagnostically useful clinical data based on both the terahertz and optical imaging data.

APPLICATIONS

• Potential applications of the proposed technology include diagnosis of:
• Cancerous tumors
• Inflammation and bleeding in the respiratory and gastrointestinal tract

ADVANTAGES

• Increased signal-to-noise ratio over conventional terahertz imaging system by several orders of magnitude
• Increased detection resolution and detectable depths in the biological tissue
• Reduced lateral scan time
• Compatible with conventional endoscopes

STATE OF DEVELOPMENT

The UCLA researchers have developed and characterized plasmonic photoconductive terahertz sources and detectors. Currently, efforts are being made to integrate the terahertz imaging systems into conventional endoscopes and test them in ex-vivo biological tissues and organs. The proposed terahertz imaging system is expected to offer: 3 mm detectable depth into biological tissues, ~30 μm depth resolution, sub-millimeter lateral resolution, and ~1 ms scan time for each 3 x 3 pixel set.

PATENT STATUS

Country	Type	Number	Dated	Case
Patent Cooperation Treaty	Reference for National Filings	WO201619630	12/08/2016	2015-815

Patent Pending

RELATED MATERIALS

• N. T. Yardimci, M. Jarrahi, "High power telecommunication-compatible photoconductive terahertz emitters based on plasmonic nano-antenna arrays", Applied Physics Letters, 109, 191103, 2016

Abstract-Invited paper: Development of terahertz endoscopic system for cancer detection

P. Doradla and R. H. Giles
http://scholar.harvard.edu/pad/publications/invited-paper-development-terahertz-endoscopic-system-cancer-detection

Terahertz (THz) imaging is emerging as a robust platform for a myriad of applications in the fields of security, health, astronomy and material science. The terahertz regime with wavelengths spanning from microns to millimeters is a potentially safe and noninvasive medical imaging modality for detecting cancers. Endoscopic imaging systems provide high flexibility in examining the interior surfaces of an organ or tissue. Researchers have been working on the development of THz endoscopes with photoconductive antennas, which necessarily operate under high voltage, and require at least two channels to measure the reflected signal from the specimen. This manuscript provides the design and imperative steps involved in the development of a single-channel terahertz endoscopic system. The continuous-wave terahertz imaging system utilizes a single flexible terahertz waveguide channel to transmit and collect the back reflected intrinsic terahertz signal from the sample and is capable of operation in both transmission and reflection modalities. To determine the feasibility of using a terahertz endoscope for cancer detection, the co- and cross-polarized terahertz remittance from human colonic tissue specimens were collected at 584 GHz frequency. The two dimensional terahertz images obtained using polarization specific detection exhibited intrinsic contrast between cancerous and normal regions of fresh colorectal tissue. The level of contrast observed using endoscopic imaging correlates well with the contrast levels observed in the free space ex vivo terahertz reflectance studies of human colonic tissue. The prototype device developed in this study represents a significant step towards clinical endoscopic application of THz technology for in vivo colon cancer screening.