Scientists have developed a new way to create electromagnetic Terahertz (THz) waves or T-rays – the technology behind full-body security scanners. The researchers behind the study say their new stronger and more efficient continuous wave T-rays could be used to make better medical scanning gadgets and may one day lead to innovations similar to the ‘tricorder’ scanner used in Star Trek.
In the study, researchers from the Institute of Materials Research and Engineering (IMRE), a research institute of the Agency for Science, Technology and Research (A*STAR) in Singapore, and Imperial College London in the UK have made T-rays into a much stronger directional beam than was previously thought possible, and have done so at room-temperature conditions. This is a breakthrough that should allow future T-ray systems to be smaller, more portable, easier to operate, and much cheaper than current devices.
The scientists say that the T-ray scanner and detector could provide part of the functionality of a Star Trek-like medical ‘tricorder’ – a portable sensing, computing and data communications device – since the waves are capable of detecting biological phenomena such as increased blood flow around tumorous growths. Future scanners could also perform fast wireless data communication to transfer a high volume of information on the measurements it makes.
T-rays are waves in the far infrared part of the electromagnetic spectrum that have a wavelength hundreds of times longer than those that make up visible light. Such waves are already in use in airport security scanners, prototype medical scanning devices and in spectroscopy systems for materials analysis. T-rays can sense molecules such as those present in cancerous tumours and living DNA, since every molecule has its unique signature in the THz range. They can also be used to detect explosives or drugs, for gas pollution monitoring or non-destructive testing of semiconductor integrated circuit chips.
Current T-ray imaging devices are very expensive and operate at only a low output power, since creating the waves consumes large amounts of energy and needs to take place at very low temperatures.
In the new technique, the researchers demonstrated that it is possible to produce a strong beam of T-rays by shining light of differing wavelengths on a pair of electrodes – two pointed strips of metal separated by a 100 nanometre gap on top of a semiconductor wafer. The structure of the tip-to-tip nano-sized gap electrode greatly enhances the THz field and acts like a nano-antenna to amplify the wave generated. In this method, THz waves are produced by an interaction between the electromagnetic waves of the light pulses and a powerful current passing between the semiconductor electrodes. The scientists are able to tune the wavelength of the T-rays to create a beam that is useable in the scanning technology.
Lead author Dr Jing Hua Teng, from A*STAR

Aberdeen researchers have discovered how a controversial but effective treatment in psychiatry acts on the brain in people who are severely depressed.
Electroconvulsive therapy or ECT – which involves anaesthetising a patient and electrically inducing a seizure – is the most potent treatment option for patients with serious mood disorder.
Despite being used successfully in clinical practice around the world for more than 70 years, the underlying mechanisms of ECT have so far remained unclear.
Now a multidisciplinary team of clinicians and scientists at the University of Aberdeen, Scotland, has shown for the first time that ECT affects the way different parts of the brain involved in depression

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A team of 18 researchers at Moffitt Cancer Center in Tampa have found that treating high-risk, soft tissue sarcoma patients with a combination of implanted dendritic cells (immune system cells) and fractionated external beam radiation (EBRT) provided more than 50 percent of their trial patients with tumour-specific immune responses lasting from 11 to 42 weeks.
‘Sarcomas are relatively rare forms of cancer with about 10,000 new cases in the U.S. annually,’ said study co-author Dmitry Gabrilovich, M.D., Ph.D., senior member of the Moffitt Department of Immunology.
The authors note that because 50 percent of patients with large, high-grade soft tissue sarcomas develop distant metastasis, new, effective treatments are needed.
‘Unfortunately, conventional therapy for large, high-grade tumours is frequently systematically ineffective, making this a very deadly problem,’ Gabrilovich said.
According to the researchers, administration of dendritic cells has been found to be a promising method for producing an immune response because dendritic cells process antigen material and present it to other immune cells. Dendritic cells act as immune system messengers.
‘Many studies have shown that preoperative radiotherapy and surgery is effective in treating many soft tissue sarcomas with high-risk features,’ said Gabrilovich. ‘We designed our study to investigate the effect of combining the administration of dendritic cells and EBRT for patients with soft tissue, high-risk sarcomas.’
The researchers hypothesised that if dendritic cell implants were combined with EBRT (the most common kind of radiotherapy treatment that not only can kill tumour cells but release tumour antigens) the combination therapy might be complimentary when the dendritic cells helped process tumour antigens released by the EBRT treatment.
‘The combination treatment resulted in dramatic increases in immune T cells in the tumours,’ explained Gabrilovich. ‘The presence of T cells in the tumours positively correlated with the development of tumour-specific immune responses.’
An important finding in this study was that no patient had significant tumour specific immune responses before the combined therapy. After the combination treatment, tumour specific responses were observed in 52.9 percent of trial patients.
The researchers reported that the combination treatment was ‘well tolerated’ and that 12 of the 17 patients in the clinical trial were ‘progression free’ after one year.
The authors concluded that given that the combination therapy proved effective in creating a potent anti-tumor response and was safe, producing no adverse side effects, larger trials with greater numbers of patients were warranted. Moffitt Cancer Center