Photoacoustic Tomography

and, Lihong V. Wang; Wu, Hsin‐I

doi:10.1002/9780470177013.ch12

Cited by 3 publications

(1 citation statement)

References 64 publications

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“…12 These techniques, however, have a variety of limitations including the size of the imaging volume, temperature range, and limited spatial and temporal resolution. Photoacoustic tomography (PAT) is an imaging modality that combines high optical absorption contrast with the high spatial resolution of ultrasound, 1,11 thus achieving a resolution of < 100 µm at a depth of a few centimeters, 4 as well as high sensitivity and contrast. Photoacoustic thermometry further exploits the temperature dependence of the Grüneisen parameter of tissues or tissue-mimicking materials which leads to changes in the recorded photoacoustic signal amplitude with temperature and can thus be used to determine the temperature of that tissue.…”

Section: Introductionmentioning

confidence: 99%

Test materials for characterising heating from HIFU devices using photoacoustic thermometry

Bakaric

Zeqiri

Cox

et al. 2020

Photons Plus Ultrasound: Imaging and Sensing 2020

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High intensity focused ultrasound (HIFU) is a non-invasive thermal therapy during which a focused ultrasound beam is used to destroy cells within a confined volume of tissue. Due to its increased use and advancements in treatment delivery, various numerical models are being developed for use in treatment planning software. In order to validate these models, as well as to perform routine quality checks and transducer characterisation, a temperature monitoring technique capable of accurately mapping the temperature rise induced is necessary. Photoacoustic thermometry is a rapidly emerging technique for non-invasive temperature monitoring, where the temperature dependence of the Grüneisen parameter leads to changes in the recorded photoacoustic signal amplitude with temperature. In order to use this technique to assess heating induced by HIFU in a metrology setting, a suitable test material must first be selected that exhibits an increase in the generated photoacoustic signal with temperature. In this study, the temperature dependence of the photoacoustic conversion efficiency (µ a Γ) of several tissue-mimicking materials was measured for temperatures between 22 • C and 50 • C. Materials included were agar-based phantoms, copolymer-in-oil, gel wax, PVA cryogels, PVCP and silicone. This information provided a basis for the development of a volumetric phantom, which was sonicated in a proof-of-concept integrated photoacoustic thermometry system for monitoring of HIFU-induced heating. The results show the suitability of agar-based phantoms and photoacoustic thermometry to image the 3D heat distribution generated by a HIFU transducer.

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Section: Introductionmentioning

confidence: 99%

Test materials for characterising heating from HIFU devices using photoacoustic thermometry

Bakaric

Zeqiri

Cox

et al. 2020

Photons Plus Ultrasound: Imaging and Sensing 2020

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High‐Precision Photoacoustic Neural Modulation Uses a Non‐Thermal Mechanism

Chen,

Yu,

Shi

et al. 2024

Advanced Science

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Neuromodulation is a powerful tool for fundamental studies in neuroscience and potential treatments of neurological disorders. Both photoacoustic (PA) and photothermal (PT) effects are harnessed for non‐genetic high‐precision neural stimulation. Using a fiber‐based device excitable by a nanosecond pulsed laser and a continuous wave laser for PA and PT stimulation, respectively, PA and PT neuromodulation is systematically investigated at the single neuron level. These results show that to achieve the same level of neuron activation recorded by Ca2+ imaging, the laser energy needed for PA stimulation is 1/40 of that needed for PT stimulation. The threshold energy for PA stimulation is found to be further reduced in neurons overexpressing mechano‐sensitive channels, indicating direct involvement of mechano‐sensitive channels in PA stimulation. Electrophysiology study of single neurons upon PA and PT stimulation is performed by patch clamp recordings. Electrophysiological features induced by PA are distinct from those by PT, confirming that PA and PT stimulation operate through different mechanisms. These insights offer a foundation for the rational design of more efficient and safer non‐genetic neural modulation approaches.

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Multispectral interlaced sparse sampling photoacoustic tomography based on directional total variation

Zhang

et al. 2022

Computer Methods and Programs in Biomedicine

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Photoacoustic Tomography

Abstract: The paper contains a simple approach to reconstruction in Thermoacoustic and Photoacoustic Tomography. The technique works for any geometry of point detectors placement and for variable sound speed satisfying a non-trapping condition. A uniqueness of reconstruction result is also obtained.

Cited by 3 publications

References 64 publications

Test materials for characterising heating from HIFU devices using photoacoustic thermometry

Test materials for characterising heating from HIFU devices using photoacoustic thermometry

High‐Precision Photoacoustic Neural Modulation Uses a Non‐Thermal Mechanism

Multispectral interlaced sparse sampling photoacoustic tomography based on directional total variation

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