Terahertz sensors have found their way into many industrial applications, though undertaking regular reference measurements could be inconvenient on some occasions. A sensor with a self-referencing (SR) mechanism (in a linear configuration) is designed and manufactured to tackle the challenge. The sensor head is used on Lithium Iron Phosphate (LFP) cathodes to report the thickness and refractive index of the material.

Terahertz pulsed imaging (TPI) is a relatively new, non-ionising and non-destructive imaging technique for studying hard tissues which does not require tooth section preparation, unlike transmission microradiography (TMR). If TPI can measure the depths of caries/demineralisation lesions accurately the same tooth samples could be reused and remeasured during in vitro and in situ studies on de- and/or remineralisation. The aim of this study was to compare TPI and TMR for measuring the depths of a range of artificially induced bovine enamel demineralised lesions in vitro. Bovine slabs with artificial caries, induced to different levels of demineralisation by two different but standard demineralisation techniques (‘acid gel’ and ‘carbopol’) were measured by TPI and TMR and the readings compared. The set of TPI/TMR measurements obtained on the gel-demineralised slabs showed an extremely high coefficient of determination (r2 = 0.995). Detailed analysis of the results and theoretical considerations (involving the relationship between refractive index profiling and mineral loss profile) are used to explain the findings and show that for acid gel lesions TPI is measuring demineralisation in the range of 47% of that of TMR depth plus an intercept of 16 µm, with further calculations allowing the TMR depths to be determined to within 5% using TPI.

As terahertz pulsed imaging (TPI) is a non-ionising and non-destructive, three-dimensional technique it can be used for studying hard tissues without requiring sample sectioning, unlike for example, transmission microradiography (TMR). If TPI can measure the depths of demineralised lesions in teeth samples accurately, the same samples could be re-used and re-measured during in vitro and in situ studies on de-and/or re-mineralization. In this study we compare TPI and TMR for the measurement of the depths of a range of artificially-induced lesions in vitro. Detailed analysis of the results and theoretical considerations reveal how the "Gold Standard" TMR depths can be determined non-invasively to within 5% using TPI.

Terahertz pulsed imaging (TPI) is an emerging modality for medical applications. TPI uses pulses of electromagnetic radiation covering a frequency range of 0.1-3 terahertz. These frequencies are nonionizing, provide submillimeter resolution and penetrate several millimeters into tissue. We have developed a fiber coupled hand held TPI scanner for use in medical imaging. We report on preliminary studies using the system in dermatological applications. This study demonstrates the potential of TPI to image skin and encourages further studies in using the system as a surgical aid for identifying tumor margins.

There are unresolved clinical problems that require the provision of accurate 3-D images of tissue structures such as teeth. In particular, measurements of dental enamel thickness are necessary to quantify problems associated with enamel erosion, yet currently there is no nondestructive method to obtain this information. We present a method that relies on the use of pulsed terahertz radiation to gain 3-D information from dental tissues. We discuss results from 14 samples and demonstrate that we can reliably and accurately quantify enamel thickness. We show that in a series of 22 surfaces, we can image pertinent subsurface features 91% of the time. Example images are shown where structures in teeth at depth are rendered accurate to within 10 microm. We discuss issues that arise using this imaging method and propose ways in which it could be used in clinical practice.

TeraHertz Pulse Imaging (TPI) is a relatively new imaging modality for medical and dental imaging. The aim of the present study was to make a preliminary assessment of the potential uses of TPI in clinical dentistry, particularly in relation to caries detection and the detection and monitoring of erosion. Images were obtained in vitro using a new TPI system developed by TeraView Ltd.We present data showing that TPI in vitro images of approximal surfaces of whole teeth demonstrate a distinctive 'shadowing' in the presence of natural carious lesions in enamel. The thickness of this enamel shadowing appears to be related to lesion depth.The use of non-ionising radiation to image such lesions non-destructively in vitro represents a significant step towards such measurements in vivo.In addition, data is presented which indicates that TPI may have a potential role in the detection and monitoring of enamel erosion. In vitro experiments on whole incisor teeth show that TPI is capable of detecting relatively small artificially induced changes in the buccal or palatal surface of the enamel of these teeth. Imaging of enamel thickness at such a resolution without ionising radiation would represent a significant breakthrough if applicable in vivo.

Summary form only given. The use of Terahertz Pulse Imaging (TPI) for the analysis of skin cancer has been investigated. Our initial experiments have focused on the analysis of basal cell carcinoma (BCC), the most common form of skin cancer. BCC seldom metastasize but can be locally very invasive. The current diagnosis of carcinomas is by visual examination, where suspicious lesions require biopsy and subsequent histological diagnosis, which is painful, time consuming and may require additional tissue removal. The use of TPI as a diagnostic tool for skin cancer is of particular interest as its long wavelengths lead to a reduction in Rayleigh scattering and a resultant axial resolution of approximately 80 /spl mu/m. The spectroscopic information of TPI may prove to be advantageous in the discrimination between tumor types, which is unattainable using other methods such as ultrasound. Through the use of TPI, unnecessary biopsies could be avoided, by providing in-vivo measurements before surgery to identify the type and depth of tumor present.