Terahertz in-line digital holography of human hepatocellular carcinoma tissue

Abstract

Terahertz waves provide a better contrast in imaging soft biomedical tissues than X-rays, and unlike X-rays, they cause no ionisation damage, making them a good option for biomedical imaging. Terahertz absorption imaging has conventionally been used for cancer diagnosis. However, the absorption properties of a cancerous sample are influenced by two opposing factors: an increase in absorption due to a higher degree of hydration and a decrease in absorption due to structural changes. It is therefore difficult to diagnose cancer from an absorption image. Phase imaging can thus be critical for diagnostics. We demonstrate imaging of the absorption and phase-shift distributions of 3.2 mm × 2.3 mm × 30-μm-thick human hepatocellular carcinoma tissue by continuous-wave terahertz digital in-line holography. The acquisition time of a few seconds for a single in-line hologram is much shorter than that of other terahertz diagnostic techniques, and future detectors will allow acquisition of meaningful holograms without sample dehydration. The resolution of the reconstructions was enhanced by sub-pixel shifting and extrapolation. Another advantage of this technique is its relaxed minimal sample size limitation. The fibrosis indicated in the phase distribution demonstrates the potential of terahertz holographic imaging to obtain a more objective, early diagnosis of cancer.

Compact All-Quantum-Dot-Based Tunable THz Laser Source

“…Such laser source emitting tunable THz radiation is of great interest for a number of applications, including indoor communications [27,28], biomedical imaging [29,30], spectroscopy [31,32], homeland security and defense [33,34], among others.…”

Application of autofocusing methods in continuous-wave terahertz in-line digital holography

“…Compared with the detectors which obtain phase and amplitude simultaneously, terahertz digital holography is a full-field phase-contrast method without scanning. In the past decade, many researchers have explored and demonstrated the imaging technology of terahertz digital holography with different schematics like millimeter-wave Fresnel offaxis digital holography [4], pulsed terahertz digital holography [5], tunable terahertz source holographic imaging [6], continuouswave terahertz digital holography based on thermal sensors [7][8][9][10][11][12][13][14][15] including Gabor in-line digital holography [7][8][9][10][11][12], phase retrieval for terahertz digital holography [9], biological specimen detection [10][11][12], and reconstruction research on terahertz off-axis digital holography [12][13][14][15].…”

Perfect digital holographic imaging with high resolution using a submillimeter-dimension CCD sensor

“…Moreover, DHM offers significant advantages over conventional microscopy in accessibility to quantitative amplitude and phase information, and in flexible digital processing such as storage, filtering, auto-focusing, aberration compensation, and display. DHM has been widely used in many fields such as biomedical science [2][3][4][5][6][7], micro-and nano-fabrication [8][9][10], materials science [11][12][13], the particle field [14][15][16][17], atomic physics [18], and the thermal energy field [19]. Nevertheless, the resolution and image quality of the most commonly used pre-magnification digital holographic microscopy (Pre-MDHM) and post-magnification digital holographic microscopy (Post-MDHM) are restricted by the photosensitive dimensions and the pixel size of the sensor, which has greatly limited the application of DHM.…”