FIG. 2.3 Trade-offs in the use of patients, physical phantoms, and digital phantoms in medical imaging. More about this image found in Trade-offs in the use of patients, physical phantoms, and digital phantoms ...

FIG. 4.18 B-scans of a bilayer phantom (a) before and [(b) and (c)] after strain compounding, plotted with a logarithmic color scale. Strain compounding (b) before and (c) after applying affine-transformation distortion correction. Image area is 135 × 585 µm². Adapted from Kennedy, B. F. et al., Opt. Lett. 35 (14), 2445–2447 (2010). Copyright 2010 The Optical Society. More about this image found in B-scans of a bilayer phantom (a) before and [(b) and (c)] after strain comp...

FIG. 5.14 Changes of a speckle pattern in a homogeneous silicone phantom under an increasing compressive load applied to the top of the sample from (a) to (d). Note that the shape of the black outline changes as the load increases, highlighting changes in the speckle pattern. Image dimensions are 50 × 50 µm². Reprinted by permission from Kennedy, B. F. et al., Optical Coherence Tomography: Technology and Applications, 2nd ed., edited by W. Drexler and J. G. Fujimoto (Springer International Publishing, Cham, 2015), pp. 1007–1054. Copyright 2015 Springer Nature Customer Service Centre GmbH: Springer Nature. More about this image found in Changes of a speckle pattern in a homogeneous silicone phantom under an inc...

FIG. 5.16 (a) OCT B-scan of a silicone phantom containing TiO₂ scatterers and a stiff inclusion undergoing sinusoidal loading. Vibration amplitude maps for the (b) STd OCE method and (f) phase-sensitive method are also shown, as are the corresponding strain elastograms [(c) and (g)]. A-scans from the location indicated by the red arrow in (a) are shown for (d) OCT, and (e) vibration amplitude for the STd OCE method (blue line) and phase-sensitive method (red line), with dashed lines indicating the inclusion boundary. Note that the vibration amplitude map generated by STd OCE in (b) is less noisy in the low signal-to-noise ratio (SNR) region at the bottom of the image compared to that generated by phase-sensitive detection (f), which impacts the noise in the elastograms (c) and (g) accordingly. Reprinted with permission from Kennedy, B. F. et al., Biomed. Opt. Express 3 (12), 3138–3152 (2012b). Copyright 2012 The Optical Society. More about this image found in (a) OCT B-scan of a silicone phantom containing TiO₂ scatterers ...

FIG. 6.10 STd OCE compared to phase-sensitive vibrational OCE for a silicone phantom with a stiff inclusion in a softer bulk. (a) OCT structural image; (b) vibration amplitude image; and (c) elastogram for STd OCE; (d) OCT A-scan; and (e) vibration amplitude plots for STd OCE (blue) and phase-sensitive vibrational OCE (red) at the lateral position indicated by the red arrow in (a), where the dashed lines in (d) and (e) indicate the boundaries between the soft bulk and hard inclusion; (f) vibration amplitude image; and (g) elastogram for phase-sensitive vibrational OCE. Reproduced with permission from Kennedy, B. F. et al., Biomed. Opt. Express 3 (12), 3138–3152 (2012). Copyright 2012 The Optical Society. More about this image found in STd OCE compared to phase-sensitive vibrational OCE for a silicone phantom ...

FIG. 7.5 Strain tensor imaging of a hollow cavity phantom under uniaxial compressive loading. OCT (a) en face and (b) B-scan images overlaid with displacement fields. Purple and orange dashed lines represent the locations of cross sections. (c) Local axial strain elastogram overlaid with the OCT B-scan. (d) En face and (e) B-scan of the dilation magnitude of the hollow cavity phantom. Scale bars represent 500 µm. Adapted with permission from Wijesinghe, P. et al., IEEE J. Sel. Top. Quantum Electron. 25 (1), 1–12 (2019). Copyright 2019 IEEE. More about this image found in Strain tensor imaging of a hollow cavity phantom under uniaxial compressive...

FIG. 7.6 Illustration of optical palpation using an inclusion phantom. Schematic diagrams of unloaded (a) and loaded (b) layer-sample system and the corresponding OCT B-scans in (c) and (d), respectively. l₀(x, y) and l(x, y) represent the initial layer thickness and loaded layer thickness, respectively. ε(x, y) represents bulk strain in the layer. (e) Stress–strain curve of the compliant layer. (f) En face OCT image of the phantom. (g) Optical palpogram of the phantom. Scale bars represent 2 mm. Adapted with permission from Kennedy, K. M. et al., Opt. Lett. 39 (10), 3014–3017 (2014b). Copyright 2014 The Optical Society. More about this image found in Illustration of optical palpation using an inclusion phantom. Schematic dia...

FIG. 7.7 Illustration of QME. (a) OCT B-scan of a layer-phantom system. (b) Stress–strain curve of the layer. (c) Layer stress map. (d) Unloaded (ϕ_U(x, z)) and loaded (ϕ_L(x, z)) phase images. (e) Phase difference (Δϕ(x, z)) image. Strain images at the (f) x-z and (g) x-y planes, respectively. (h) Elasticity image at the x-y plane. Scale bars represent 500 µm. More about this image found in Illustration of QME. (a) OCT B-scan of a layer-phantom system. (b) Stress–s...

FIG. 7.4 Comparison between different strain estimation methods using experimental data from an inclusion phantom. (a) OCT B-scan of the inclusion phantom. Strain elastograms using (b) the finite difference, (c) OLS, (d) WLS, and (e) vector methods with no spatial averaging in y. The effect of spatial averaging of independent speckle realizations in y on the elastogram quality for the (f) WLS and (g) vector methods. OCT signal-to-noise ratio (SNR) and strain as a function of lateral position at a depth of 470 µm below the phantom surface [indicated by blue solid lines in (a)–(g)] are shown in (h)–(n). Scale bars represent 400 µm. More about this image found in Comparison between different strain estimation methods using experimental d...

FIG. 8.6 Elastography resolution characterization in wave-based OCE. In (a)-top wave propagation generated at the center of a two-sided phantom (softer-to-stiffer transition) tissue-mimicking phantom. In (a)-bottom, the elastogram (i.e., wave speed map) was calculated based using a wavelength estimator. Average wave speeds in both regions show a differentiated elasticity between both phantom halves. (b) Lateral-dependent speed transition plot obtained from the elastogram in (a) fitted to the sigmoid function [Eq. (4.7)]. The spatial derivate of the sigmoid plot was obtained to calculate the full-width half maximum (FWHM) spreading of the pulse. Reproduced from Zvietcovich, F. et al., Opt. Lett. 45 (23), 6567–6570 (2020a). Copyright 2020 Optica. More about this image found in Elastography resolution characterization in wave-based OCE. In (a)-top wave...

FIG. 2.4 Anecdotal illustration of the types of phantoms used in x-ray, CT, and nuclear medicine imaging. More about this image found in Anecdotal illustration of the types of phantoms used in x-ray, CT, and nucl...

FIG. 7.1 Illustration of one implementation of compression OCE. Compression OCE for the states of (a) initial contact, (b) pre-strain, and (c) local strain. (d) Experimental displacement map of the inclusion phantom and the corresponding (e) ideal and (f) experimental displacement-depth profiles a... More about this image found in Illustration of one implementation of compression OCE. Compression OCE for ...

FIG. 5.13 An illustration of correlation stability mapping for a two-layer silicone phantom consisting of a soft upper and a stiff lower layer. (a) OCT image of the phantom. (b) A representative correlation stability map showing higher correlation in the stiff layer compared to the soft layer. (c)–(f) Correlation stability maps for monotonically increasing strain; in these images, the stiff layer exhibits slower decorrelation than the soft layer. Reprinted with permission from Zaitsev, V. Y. et al., J. Biomed. Opt. 19 (2), 021107 (2014a). Copyright 2014 SPIE. More about this image found in An illustration of correlation stability mapping for a two-layer silicone p...

FIG. 3.1 CT images of a homogeneous water phantom scanned and reconstructed under different conditions: (a) Reference dose (100%, which is a CTDIvol of 2.0 mGy) with 2 mm thickness and a smooth (B20) reconstruction kernel; (b) 50% of reference dose (approximately 1.0 mGy) with 1 mm thickness and m... More about this image found in CT images of a homogeneous water phantom scanned and reconstructed under di...

FIG. 3.2 Plot of the mean Hounsfield unit (HU) of the water phantom for each condition shown in Fig. 3.1 . Note that the values are very close to 0 (as expected for water) except for the very low dose scan of condition (d). More about this image found in Plot of the mean Hounsfield unit (HU) of the water phantom for each conditi...

FIG. 3.4 Images from the dense cork section of the CCR radiomics phantom [images from TCIA website ( Mackin et al., 2017a )]: (a) 400 mAs with I31f-2; (b) 50 mAs with I31f-2; (c) I26f-2 with 65 mAs; (d) I70f-2 with 65 mAs. More about this image found in Images from the dense cork section of the CCR radiomics phantom [images fro...

FIG. 12.3 (a) Anthropomorphic Lungman N1 thorax phantom; (b) vascular insert (Kyotokagaku Inc., Tokyo, Japan); (c) various synthetic nodules with a range of shapes and sizes; (d) a view of inserted synthetic nodules within foam receptables, within the vascular structure of the anthropomorphic thor... More about this image found in (a) Anthropomorphic Lungman N1 thorax phantom; (b) vascular insert (Kyotoka...

FIG. 6.11 Experimental (left column) and simulated (right column) compression OCE scans of a silicone phantom, consisting of a stiff inclusion embedded in a softer, homogeneous, bulk. (a) Experimental and (b) simulated OCT images. (c) Experimental and (d) simulated relative axial displacement within the loaded phantom. (e) Experimental and (f) simulated strain elastograms in units of milli-strain (mε). The axial strain field varies considerably around the inclusion, even though the material is mechanically homogeneous. Adapted with permission from Chin, L. et al., Biomed. Opt. Express 5 (9), 2913–2930 (2014). Copyright 2014 The Optical Society. More about this image found in Experimental (left column) and simulated (right column) compression OCE sca...

FIG. 6.3 An example of measurement of the natural frequency, ω_n, using the underdamped free vibration model, compared to Young's modulus, E, measured from transverse-wave OCE. (a) Representative normalized tissue damping oscillations for 0.75–2% agar phantoms. (b) Representative frequency components from Fourier analysis of tissue oscillations. The dominant frequencies (from 127 Hz to 774 Hz) were considered as the natural frequencies for the agar phantoms. (c) and (d) Quantifications (mean ± standard deviation) of natural frequencies and damping ratios, respectively, by fitting the transient responses. (e) Young's moduli (mean ± standard deviation) by transverse-wave OCE. (f) Linear fit of ω_n (mean ± frequency resolution of 2 Hz) against E (mean ± standard deviation). Reproduced with permission from Lan, G. et al., Biomed. Opt. Express 11 (6), 3301–3318 (2020). Copyright 2020 The Optical Society. More about this image found in An example of measurement of the natural frequency, ω_n...