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Molecular Imaging True Color Spectroscopic (METRiCS) Optical Coherence Tomography
Published in Troy Farncombe, Krzysztof Iniewski, Medical Imaging, 2017
As a final demonstration of the capabilities of METRiCS OCT, we present images acquired in vivo from a CD1 nu/nu normal mouse dorsal skinfold window chamber model [47]. Molecular contrast is demonstrated in this model for both endogenous and exogenous contrast. For imaging of endogenous contrast due to Hb absorption, the mouse was anesthetized and the window chamber was removed for imaging. Conventional OCT imaging of the data reveals tissue structures, as seen in Figure 3.22a. Here, several histological structures are evident, including the muscle layer, the lumen of blood vessels—including small capillaries—and the subcutaneous layer [48]. However, functional information regarding the sample is not available in this format. Using METRiCS OCT (Figure 3.22b), the spectral information reveals several interesting features: for example, the muscle layer at the surface appears relatively colorless due to low concentration of Hb, but once light traverses through the vasculature network beneath, a red shift is clearly observed due to higher concentrations of Hb. Another interesting feature is the small color variations on the top layer due to scattering from muscle and fibrous structures. Moreover, in regions below large blood vessels (>100 μm), most of the light is attenuated, thereby preventing detection of signals from below and thus creating a “shadow” effect. However, in regions without apparent blood vessels, signals are obtained throughout the full penetration depth enabled by the system.
A new approach on the lateral bored pile group effect
Published in W.F. Van Impe, W. Haegeman, Deep Foundations on Bored and Auger Piles, 2020
The behaviour of a pile belonging to a group is influenced by the interaction of this pile with one or more neighboring piles, which is known as a group effect. This concept is sometimes identified in the literature with the shadow effect. It is emphasized that in the author’s meaning these two concepts are not identical: shadow effect represents the most important component of the group effect, but not the only one. Thus in this paper the shadow effect will be considered as a distinct matter.
Interactive, in-browser cinematic volume rendering of medical images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2023
Jiayi Xu, Gaspard Thevenon, Timothee Chabat, Matthew McCormick, Forrest Li, Tom Birdsong, Ken Martin, Yueh Lee, Stephen Aylward
Volumetric shading is another relatively efficient technique to capture shadow information, sometimes referred to as shadow ray or secondary scatter. At each ray-cast sample location, a secondary ray branches off towards the light source. Production rendering often uses this method to check whether a point is occluded from the light source. For translucent media, such as medical volume data, shadow ray also carries information about the transmittance along the way and produces a global shadow effect. Perceptual studies have shown that volumetric shadow improves understanding of spatial relations and object size (Wanger et al. 1992).