Cytogenetic observations in human peripheral blood leukocytes following in vitro exposure to THz radiation: a pilot study.

Emerging technologies are considering the possible use of Terahertz radiation in different fields ranging from telecommunications to biology and biomedicine. The study of the potential effects of Terahertz radiation on biological systems is therefore an important issue in order to safely develop a variety of applications. This paper describes a pilot study devoted to determine if Terahertz radiation could induce genotoxic effects in human peripheral blood leukocytes. For this purpose, human whole blood samples from healthy donors were exposed for 20 min to Terahertz radiation. Since, to our knowledge, this is the first study devoted to the evaluation of possible genotoxic effects of such radiation, different electromagnetic conditions were considered. In particular, the frequencies of 120 and 130 GHz were chosen: the first one was tested at a specific absorption rate (SAR) of 0.4 mW g-1, while the second one was tested at SAR levels of 0.24, 1.4, and 2 mW g-1. Chromosomal damage was evaluated by means of the cytokinesis block micronucleus technique, which also gives information on cell cycle kinetics. Moreover, human whole blood samples exposed to 130 GHz at SAR levels of 1.4 and 2 mW g-1 were also tested for primary DNA damage by applying the alkaline comet assay immediately after exposure. The results obtained indicate that THz exposure, in the explored electromagnetic conditions, is not able to induce either genotoxicity or alteration of cell cycle kinetics in human blood cells from healthy subjects.

Enhanced coherent emission of terahertz radiation by energy-phase correlation in a bunched electron beam.

We report the first observation of enhanced coherent emission of terahertz radiation in a compact free electron laser. A radio-frequency (rf) modulated electron beam is passed through a magnetic undulator emitting coherent radiation at harmonics of the rf with a phase which depends on the electron drift velocity. A proper correlation between the energy and phase distributions of the electrons in the bunch has been exploited to lock in phase the radiated field, resulting in over 1 order of magnitude enhancement of the coherent emission.

Absorption and Diffusion Measurements of Biological Samples using a THz Free Electron Laser.

A compact THz Free Electron Laser (FEL) isbeing used to perform irradiation ofbiological samples to investigate possiblegenotoxic effects. In order to evaluate theexact radiation dose absorbed by the singlecomponents of the samples it is necessaryto study the optical properties of thesamples, separating the contributions tothe radiation attenuation coefficientcoming from absorption and from diffusion.Spectroscopic measurements have beenperformed on different biological samples, comparing the experimental results withtheoretical models.

THz Exposure of Whole Blood for the Study of Biological Effects on Human Lymphocytes.

The aim of the present study is toinvestigate the genotoxic effect of THzradiation in human peripheral bloodlymphocytes following 20 minutes exposureto 1 mW average power Free Electron Laserradiation in the frequency range 120-140GHz. For this purpose 9 healthy donors wereemployed and cytokinesis block techniquewas applied to study micronucleusfrequency and cell proliferation. Theresults obtained indicate that all theelectromagnetic conditions adopted so far do not alter the investigated parameters,suggesting absence of direct chromosomaldamage and alteration of cell cyclekinetics (two tailed paired Student's test:p> 0.05 in all cases).