Thermo-elastic optical coherence tomography

Wang, Tianshi; Pfeiffer, Tom; Wu, Min; Wieser, Wolfgang; Amenta, Gaetano; Draxinger, Wolfgang; Steen, Antonius F.W. van der; Huber, Robert; Soest, Gijs van

doi:10.1364/ol.42.003466

Cited by 19 publications

(7 citation statements)

References 43 publications

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“…The downward propagation was not detected due to the deterioration of phase stability with depth. The thermal expansion displacement is not evident due to much lower utilized pulsed laser fluence as compared with previous works [19][20][21]. Furthermore, the results indicate that the mechanical excitation force induced by the rapid liquid-to-gas phase transition of nanobomb contribute to the LSW generation at the lower fluence.…”

mentioning

confidence: 53%

Longitudinal elastic wave imaging using nanobomb optical coherence elastography

et al. 2019

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Wave-based optical coherence elastography (OCE) is a rapidly emerging technique for elasticity assessment of tissues having high displacement sensitivity and simple implementation. However, most current noncontact wave excitation techniques are unable to target a specific tissue site in 3D and rely on transversal scanning of the imaging beam. Here, we demonstrate that dye-loaded perfluorocarbon nanoparticles ("nanobombs") excited by a pulsed laser can produce localized axially propagating longitudinal shear waves while adhering to the laser safety limit. A phase correction method was developed and implemented to perform sensitive nanobomb elastography using ~1.5 MHz Fourier domain mode locking laser. The nanobomb activation was also monitored by detecting photoacoustic signals. The highly localized elastic waves detected by the nanobomb OCE (nb-OCE) suggest possibility of high-resolution 3D elastographic imaging. OCIS codes: (110.4500) Optical coherence tomography; (170.0110) imaging system; (150.1135) Algorithms Changes in tissue viscoelasticity are often associated with development of different pathologies, and can, therefore, be a useful biomarker for monitoring disease onset and progression [1]. Wave-based optical coherence elastography (OCE) is an emerging powerful technique capable of nanometer-scale displacement sensitivity, which has enabled biomechanical assessments of tissues with minimal excitation forces [2], such as pneumatic, Lorentz, and acoustic radiation forces. However, these techniques usually cannot target *

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mentioning

confidence: 53%

Longitudinal elastic wave imaging using nanobomb optical coherence elastography

et al. 2019

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“…Previously, we demonstrated the concept of thermo-elastic (TE-OCT), a hybrid imaging technique between PAI and PhS-OCT [33]. When tissue absorbs a laser pulse with a duration that is shorter than the thermal relaxation time of the tissue, thermal confinement is achieved.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic thermo-elastic optical coherence tomography for tissue characterization

Deen

Beusekom

Pfeiffer

et al. 2022

Biomedical Spectroscopy, Microscopy, and Imaging II

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Optical imaging techniques that provide free space, label free imaging are powerful tools in obtaining structural and biochemical information in biological samples. To date, most of the optical imaging technologies create images with a specific contrast and require multimodality integration to add additional contrast. In this study, we demonstrate spectroscopic Thermoelastic Optical Coherence Tomography (TE-OCT) as a potential tool in tissue identification. TE-OCT creates images based on two different forms of contrast: optical reflectance and thermo-elastic deformation. TE-OCT uses short laser pulses to induce thermo-elastic tissue deformation and measures the resulting surface displacement using phase-sensitive OCT. In this work we characterized the relation between thermo-elastic displacement and optical absorption, excitation, fluence and illumination area. The experimental results were validated with a 2dimensional analytical model. Using spectroscopic TE-OCT, the thermo-elastic spectra of elastic phantoms and tissue components in coronary arteries were extracted. Specific tissue components, particularly lipid, an important biomarker for identifying atherosclerotic lesions, can be identified in the TE-OCT spectral response. As a label-free, free-space, dual-contrast, all-optical imaging technique, spectroscopic TE-OCT holds promise for biomedical research and clinical pathology diagnosis.

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“…2,3 Previously, we introduced the concept of "Thermo-elastic optical coherence tomography (TE-OCT)". 4 Rather than "listening" to the acoustic wave by use of an ultrasound transducer as in photoacoustic imaging, TE-OCT "visualises" the thermo-elastic displacement by measuring the Doppler OCT phase shift. Using a forward-looking probe to scan the sample, cross-sectional TE-OCT images were acquired which provides tissue type information in addition to the tissue morphology offered by conventional OCT.…”

Section: Introductionmentioning

confidence: 99%

“…where Φ is the Doppler OCT phase shift, n is the refractive index of the sample and λ o is the centre wavelength of the OCT laser source. 4 In this study, we advance the TE-OCT technology and build a microscopic setup, by means of thermo-elastic optical coherence microscopy (TE-OCM). Using TE-OCM, we aim to achieve high speed, label-free and free space chemical microscopic imaging.…”

Section: Introductionmentioning

confidence: 99%

Thermo-elastic optical coherence microscopy

Deen¹,

Pfeiffer²,

Beusekom

et al. 2020

Advanced Chemical Microscopy for Life Science and Translational Medicine

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The absorption of laser pulses by tissue leads not only to the generation of acoustic waves, but also to nanometer to sub-micrometer scale displacement. After the initial expansion, a quasi-steady state is achieved in a few microseconds. Previously we introduced the concept of thermo-elastic optical coherence tomography (TE-OCT) to "visualise" the rapid thermo-elastic expansion by measuring the Doppler phase shift rather than "listening" to the acoustic wave as in photoacoustic imaging. In this study, we built a microscopic setup for high-speed 3D TE-OCT imaging, by means of thermo-elastic optical coherence microscopy (TE-OCM). The repetition rate of pulsed laser was set to 100 Hz and the line rate of the OCT system is 1.5 MHz. The OCT beam and the laser pulse were focused upon the same location on the sample FWHM spot sizes of 300 µm for the pulsed laser and 40 µm FWHM for the OCT beam. For each laser pulse, an M-mode OCT image consisting of 90 A-lines was acquired. The Doppler phase shift was extracted by comparing the phase signal before and after the pulse arrival. Within 6 minutes, a 3D TE-OCM image (10 x 10 x 4 mm 3 ) can be acquired and processed. Imaging experiments were carried out in swine meat using 1210 nm excitation wavelength to highlight lipid in tissue. The results show that no significant displacement was detected in swine muscle while strong displacement was observed in lipid, owing to the optical absorption features. Furthermore, fatty tissue is easily identified in the 3D TE-OCM image while the conventional OCT images provides the structural information.

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Thermo-elastic optical coherence tomography

Cited by 19 publications

References 43 publications

Longitudinal elastic wave imaging using nanobomb optical coherence elastography

Longitudinal elastic wave imaging using nanobomb optical coherence elastography

Spectroscopic thermo-elastic optical coherence tomography for tissue characterization

Thermo-elastic optical coherence microscopy

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