Tuesday 31 July 2012

TeraView trials in vivo THz spectroscopy


Optics.org
TeraView trials in vivo THz spectroscopy
16 Jul 2012
Approval from the MHRA allows testing of the technique as a means to detect breast cancer tissue.
THz spots the difference in breast cancer tissue
THz spots the difference in breast cancer tissue
The application of terahertz (THz) spectroscopy to the in vivo detection of cancerous tissues during breast cancer surgery will be assessed at Guy's Hospital, London, when clinical trials begin later in 2012.

The program, now approved by the UK's Medicines and Healthcare products Regulatory Agency (MHRA), will employ a system developed by UK-based THz specialists TeraView as an intra-operative probe during the surgery. The aim is to assist surgeons in better identifying and more effectively removing cancer tissues in the breast.

"This is the first such in vivo test to be carried out, as far as we are aware," commented Ian Grundy of TeraView to optics.org. "The surgeon will use a hand-held probe to examine the margins of the breast tissues, to check that they are cancer-free and that no cancerous tissue remains inside the incision. Our system gives real-time analysis in the theater, so the surgeon can take the necessary action."

This contrasts with the current need for separate laboratory histology tests to assess the effectiveness of cancer removal after the fact, a process which takes considerably longer and often results in patients having to then be recalled for a second surgical procedure.

A recent British Medical Journal study stated that one in five women who had breast-conserving surgery found themselves in this position and obliged to undergo further procedures, while previous coverage on Optics.org put the figure substantially higher. Grundy puts the proportion at around 30 percent; but whatever the exact number, the need for improvement is clear.

"The intention is to use THz technology to provide better clinical outcomes, reduce the stress on patients, lower the number of re-operations, and also cut costs," said Grundy.

Spectral analysis
TeraView has been developing THz technology since the company was spun-out from Toshiba Research Europe in 2001, and has already demonstrated the use of THz imaging techniques for viewing skin carcinomas. Generating quasi-3D images from reflected THz pulses can reveal the exact extent of diseased tissue more accurately than visual observation.

The mechanism by which unhealthy tissue exhibits higher contrast than its surroundings is not fully understood, but is thought to involve the absorption of THz radiation by water in the tissues, and the different hydration states of cancerous and healthy tissues.

The breast cancer study exploits this characteristic by using a THz spectrometer in an absorption mode to measure the THz refractive index and absorption coefficient spectra of the sampled tissues. For both parameters, cancerous tissue reveals a distinctly higher value than either healthy adipose tissue or healthy fibrous breast tissue.

"We can correlate this effect with the presence of cancer tissues completely, and have studied it for many years," commented Grundy. "The barriers to implementing trials to explore it further have to date been to do with making the technology sufficiently robust, and with the necessary funding."
TeraView confirmed that the MHRA-approved trial has received support from the UK's Technology Strategy Board.

Historically the main uses for THz equipment have been within universities and large research institutions, but signs of diversification have been growing. The TeraView trials are proof of that, along with the company's indication that it now has strong interest from solar, automotive, pharmaceutical and semiconductor companies in its technology.

see


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Wednesday 25 July 2012

Terahertz spectroscopy approach of the fiber orientation influence on CFRP composite solid laminates


Volume 26, Number 7 (2012), 2051-2054DOI: 10.1007/s12206-012-0513-5

Je-Woong Park, Kwang-Hee Im, David K. Hsu, Jong-An Jung and In-Young Yang

Abstract

gantryTerahertz ray (T-ray) imaging applications have provided one of the most promising new powerful nondestructive evaluation techniques, and new application systems are under process development for area applications. Detecting flaws and defects in fiber reinforced plastic (FRP) composite laminates due to flaws in FRP composite laminate that affect laminate properties, including stiffness, strength, and thermal behavior, is very important. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating the flaws in FRP solid composite laminates. Extensive experimental measurements in reflection mode were made to map out T-ray images. In particular, electromagnetic properties, such as refractive index, were estimated in this characterization procedure. The estimates of properties were in good agreement with known data. Using these characteristic material properties, we successfully demonstrated the characteristics of the T-ray behavior propagating through FRP composites. Furthermore, layup effect and flaws of FRP composite laminates were observed in reflection mode, and limitations were discussed in the T-ray processing.


for more information about large area terahertz scanners see 




Tuesday 24 July 2012

Broadband Terahertz Plasmonic Response of Touching InSb Disks


S. M. Hanham 1,*, A. I. Fernández-Domínguez1, J. H. Teng3, S. S. Ang3, K. P. Lim4, S. F. Yoon4, C. Y. Ngo3, N. Klein2, J. B. Pendry1, S. A. Maier1,*

2 Dept. of Materials, Imperial College London, South Kensington, London, SW7 2AZ, UK
3 Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore 117602, Singapore
4 Sch. of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore

DOI: 10.1002/adma.201202003


Thumbnail image of graphical abstract

Abstracts
The plasmonic behavior of dimers of touching semiconductor disks is studied experimentally in the difficult-to-realize regime where the disks are only marginally overlapping. Previous theoretical studies have shown that this geometry exhibits a highly efficient broadband response that may be very promising for light harvesting and sensing applications. By taking advantage of the plasmonic character of InSb in the terahertz regime, we experimentally confirm this broadband response and describe the associated strong field enhancement and sub-micrometer field confinement between the disks.



... Extinction spectra for the three touching dimer arrays were measured by placing them at the focal point of a Gaussian beam produced by a THz time-domain spectrometer (Teraview TPS Spectra 3000). We analyze the electromagnetic ..



For more information about the Spectra 3000 visit http://www.teraview.com/products/terahertz-pulsed-spectra-3000/index.html

Monday 23 July 2012

Surface relief structures for a flexible broadband terahertz absorber



Dong-Hyun Kim,1 Dae-Seon Kim,1 Sehyun Hwang,2 and Jae-Hyung Jang1,2,3,*

1School of Information and Communications, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea
2Research Institute for Solar and Sustainable Energies, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea
3Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, 1 Oryong-dong, Buk-gu, Gwangju 500-712, South Korea


Abstract

Terahertz (THz) absorbers with surface relief structures (SRSs) were designed and fabricated on a flexible polydimethylsiloxane(PDMS) substrate by using a stamping method. The silicon mold used for the stamping process was prepared by using a crystallographic wet etching method with 45% KOH solution at 80°C. The flexible THz absorber, consisting of micropyramids with a base width of 240 μm, demonstrated nearly perfect absorbance higher than 99% owing to the dramatically reduced surface reflectance of the SRS. The reflectance of the PDMS with the SRS was less than 1%, which is only 1/100th of that measured from a bare PDMS at frequency higher than 1 THz.











... of 240 μm. The reflectance and transmittance of the fabricated flexible PDMS-based SRS samples were measured with a terahertz time-domain spectroscopy (THz-TDS) system (TPS spectra 3000, TeraView). The THz-TDS ...


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Thursday 19 July 2012

THz spectroscopy and imaging in security applications

Palka, Norbert; Szustakowski, Mieczyslaw ;  Kowalski, Marcin ;  Trzcinski, Tomasz ;  Ryniec, Radoslaw ;  Piszczek, Marek ;  Ciurapinski, Wieslaw ;  Zyczkowski, Marek ;  Zagrajek, Przemyslaw ;  Wrobel, Janusz

Institute of Optoelectronics, Military University of Technology, Warsaw, Poland  

19th International Conference on Microwave Radar and Wireless Communications (MIKON), 2012 
Volume 1, pages 265-270


ABSTRACT

We compared terahertz transmission spectra of explosives measured by means of Time Domain Spectroscopy (TDS) and an Optical Parametric Oscillator-based system (OPO). Reflection spectra of pure explosives were measured in reflection configuration by means of TDS in the range 0.3–2.5THz. We also analyzed influence of the surface roughness on reflectance and phase spectra of RDX plastic based explosives. Next, we present a thermal phantom of human body working in THz range, which was developed for testing of THz cameras. We demonstrate the possibility of improvement of the quality of the image captured by a commercially available passive THz camera.

for full paper click here


explosives detection system


... In our investigations we exploited a commercially available spectrometer TPS 3000 from Teraview -  Fig.1a [9]. The heart of the system is a 800 nm femtosecond Ti:Sapphire laser (a pulse duration  less than 100 fs, repetition rate of 80 MHz, and average power of 300 mW). ...







for more information visit www.teraview.com

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