Mechanically switchable solid inhomogeneous phantom for performance tests in diffuse imaging and spectroscopy

Abstract

Abstract. A mechanically switchable solid inhomogeneous phantom simulating localized absorption changes was developed and characterized. The homogeneous host phantom was made of epoxy resin with black toner and titanium dioxide particles added as absorbing and scattering components, respectively. A cylindrical rod, movable along a hole in the block and made of the same material, has a black polyvinyl chloride cylinder embedded in its center. By varying the volume and position of the black inclusion, absorption perturbations can be generated over a large range of magnitudes. The phantom has been characterized by various timedomain diffuse optics instruments in terms of absorption and scattering spectra, transmittance images, and reflectance contrast. Addressing a major application of the phantom for performance characterization for functional near-infrared spectroscopy of the brain, the contrast was measured in reflectance mode while black cylinders of volumes from ≈20 mm 3 to ≈270 mm 3 were moved in lateral and depth directions, respectively. The new type of solid inhomogeneous phantom is expected to become a useful tool for routine quality check of clinical instruments or implementation of industrial standards provided an experimental characterization of the phantom is performed in advance.

Probe-hosted silicon photomultipliers for time-domain functional near-infrared spectroscopy: phantom andin vivotests

“…The nEUROPT tests were taken on an inhomogeneous solid phantom with switchable black polyvinyl chloride inclusions of different dimensions, which mimics a realistic absorption perturbation. 23 The inclusions (black cylinders with diameter and height of 3, 4, 5, and 7 mm, corresponding to an equivalent absorption variation of 0.05, 0.10, 0.17, and 0.40 cm −1 , for a volume of 1 cm 2 , respectively) were placed inside a movable cylinder (solid epoxy resin with same optical properties of the host phantom). Both lateral (Y-scan, measuring surface parallel to the inclusion movement) and depth scans (Z-scan, measuring surface perpendicular to the inclusion movement) were performed in 1-mm steps.…”

Design and construction of a solid switchable phantom for diffuse optical imaging

“…If data are normalized to the unperturbed state (i.e. with the black inclusion shifted far from the fibers), then the rod perturbation is cancelled, and the images reveal only the PVC object (data not shown) [10].…”

Broadband Time Domain Diffuse Optical Reflectance Spectroscopy: A Review of Systems, Methods, and Applications

“…Ref. [179] presents a phantom kit composed of a homogeneous epoxy resin bulk phantom with a hole, in which different epoxy resin rods can move along one direction (Figure 24a). Each rod contains a different absorption perturbation [180], thus allowing to move the inhomogeneity with respect to the position of the source-detector pair.…”