The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In vivo visualization and quantification of surface tissue edema, or ‘tissue swelling’ following injury or as diagnostic criteria for the detection of disease remains a clinical challenge. The most common method for evaluating edema is by clinical examination, during which tissue swelling and turgor are routinely examined. This technique, however, is qualitative, difficult to standardize, and requires...
Research into the application of THz frequency imaging to medical diagnostics has yielded a significant body of work reporting the properties of in vitro and ex vivo samples. However, there a dearth of in vivo imaging results owing to the practical difficulties of acquiring data of sufficient fidelity on living animal and/or human subjects. This limited data set has hindered widespread acceptance...
The effect of rough surface scattering on the contrast observed in THz medical imaging is explored. A Frequency Modulated Continuous Wave (FMCW) THz imaging system operating at a center frequency of 650 GHz with a time averaged bandwidth varied between ∼ 0.01% and 1% bandwidth was used to image rough surface targets to explore the effect of rough surface scattering on the contrast observed in THz...
Parallel T2 weighted multi slice multi echo (T2w MSME) 7T Magnetic Resonance (MR) scans and terahertz (THz) surface reflectance maps were acquired of a full thickness skin burn in a rat model to investigate the spatiotemporal evolution of terahertz reflectivity in wound responses. A comparison of uninjured and injured regions in the burn neighborhood demonstrates a 3-fold increase in T2 relaxation...
Design considerations for an off-axis parabolic mirror based THz imaging systems are presented. The distortion of THz field and its polarization profile are shown for two different configurations of off-axis parabolic mirror trains. The field and polarization distortions along the propagation path are compared with different f/# mirrors. The distortion effects were cancelled out by symmetric orientation...
A pulsed THz imaging system was used to image wound physiology in in vivo rat models. Histamines were injected subcutaneously in varying concentration and the buildup, organization, and dissipation of edema was observed in THz imagery acquired once every hour over the course of three hours. Significant shifts in edema were observed initially and then with less significant shifts noted towards the...
Electromagnetic modeling predicts that dielectric substrate windows placed above a tissue of interest alter the hydration sensitivity of reflective THz imaging systems. Furthermore, interference effects between layers (the window with the skin layers) cause the window's optical path length to change the depth probed by the imaging system. A pulsed THz imaging system operating at ∼ 500 GHz was used...
THz medical imaging has made significant advances in the years since the first results were published in the late 1990s. The field has benefited significantly from advances in source/detector technology, room temperature component operation, and extensive spectroscopic studies of the THz properties of tissue. Additionally, clinical translation of THz medical imaging technology has been aided by the...
A novel reflective THz imaging objective mirror design is presented and characterized that can switch between pairs of numerical aperture and focal length while maintaining a fixed back focal distance (BFD). This allows the user to easily explore the effect of varying spot size, depth of field and working distance paremter during medical imaging studies without the need for optical realignment. The...
Variations in water volume fraction have been investigated as a possible source of contrast in several reflective THz medical imaging applications including corneal hydration sensing and burn wound severity diagnosis. Due to surface roughness and non-planar geometry most reflective systems employ low loss windows such as quartz or sapphire to minimize the effects of the specimen's topology. This creates...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.