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Fast-scanning THz medical imaging system for clinical application

Applications for terahertz (THz) medical imaging have proliferated over the past few years due to advancements in source/detector technology and vigorous application development. While considerable effort has been applied to improving source output power and detector sensitivity, significantly less work has been devoted to improving image acquisition method and time. The majority of THz medical imaging systems in the literature typically acquire pixels by translating the target of interest beneath a fixed illumination beam. While this single-pixel whiskbroom methodology is appropriate for in vitro models, it is unsuitable for in vivo large animal and patient imaging due to practical constraints. This paper presents a scanned beam imaging system based on prior work that enables for reduced image acquisition time while allowing the source, target and detector to remain stationary. The system employs a spinning polygonal mirror and a set of high-density polyethylene (HDPE) objective lenses, and operates at a center illumination frequency of 525GHz with ~125GHz of 3dB bandwidth. The system achieves a focused beam diameter of 1.66mm and a large depth of field of <25 mm. Images of characterization targets and ex vivo tissue samples are presented and compared to results obtained with conventional fixed beam scanning systems.