THz Pulsed Imaging in Biomedical Applications

Abstract

Recent advances in technology have allowed the production and the coherent detection of sub-ps pulses of terahertz (THz) radiation. Therefore, the potentialities of this technique have been readily recognized for THz spectroscopy and imaging in biomedicine. In particular, THz pulsed imaging (TPI) has rapidly increased its applications in the last decade. In this paper, we present a short review of TPI, discussing its basic principles and performances, and its state-of-the-art applications on biomedical systems.

Terahertz spectroscopy of diabetic and non-diabetic human blood plasma pellets

“…Since the density of the pellets is also different, then it is necessary to exclude the effect of pressure during pellets pressing procedure and to normalize the THz optical properties (α and n) to the density of a pellet ρ o : E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 0 0 8 ; 1 1 6 ; 3 0 5 n norm ¼ ðn − 1Þ ρ o : (9) This assumption that α is proportional to ρ o is confirmed by the Bouguer-Lambert-Beer law and α∕ρ o has the meaning of molar extinction, i.e., the amount of absorption by one molecule. Thus α∕ρ o is the unique properties of the material in the THz frequency range.…”

“…3,4 Terahertz (THz) radiation and technologies based on it have been actively developed and increasingly used in many fields of science and technology, 5,6 including medical diagnostics and therapy. [7][8][9] In last five years, THz spectroscopy has been demonstrated as a tool for highly accurate measurement of even small quantities of sugar molecules in liquid solutions and the selective identification of different sugar molecules. In terms of biochemical analysis, THz spectroscopy can be used for quantitative determination of the global hydration state of sugar solutions.…”

Performance Evaluation of a THz Pulsed Imaging System: Point Spread Function, Broadband THz Beam Visualization and Image Reconstruction

“…In recent years, the terahertz (THz) range of the electromagnetic spectrum (0.1-10 THz) has become very attractive, due to its applications in basic science and technology [1][2][3][4][5][6]. THz photons (1 THz is equivalent to 4 meV, 300 µm and 33 cm −1 ) due to their non-ionizing nature, can be exploited for many nondestructive applications in biomedicine, metrology and quality control of industrial productions, spectroscopic investigations, environmental monitoring, art conservation, particle-accelerator physics [7][8][9][10][11][12][13][14][15], etc. In addition, THz waves can propagate through inflammable liquids without causing combustion, resulting in their being suitable for security and gas sensing purposes [16][17][18][19].…”

“…THz radiation is very sensitive to polar molecules like water whilst remaining rather transparent to non-polar molecules like plastics, ceramics, paper, cloths, fats, etc. These distinct optical responses are often the basis for both materials' characterization [20] and spectroscopic imaging [7].…”

Broadband Anisotropic Optical Properties of the Terahertz Generator HMQ-TMS Organic Crystal

“…THz radiation (1 THz∼33 cm −1 or 4 meV photon energy) has gained over the years a considerable interest due to its broad variety of applications. Starting from fundamental scientific investigations, where THz can be used as a resonant probe for the plethora of excitations in condensed matter physics [1][2][3], its applications reach also to various industrial and biomedical activities [4][5][6][7], security applications [8][9][10], and particle-accelerator physics [11,12]. Following the growing interest, a rapid development of both THz generators and detectors has been made possible thanks to novel technologies that have become available in these last two decades, such as quantum cascade lasers, photoconductive antennas, Gunn lasers, and sources based on nonlinear optical (NLO) effects.…”