Laser-Induced Fluorescence Thermometry of Heating in Water from Short Bursts of High Intensity Focused Ultrasound

Al-Qraini, Moath M.; Canney, Michael; Oweis, Ghanem F.

doi:10.1016/j.ultrasmedbio.2012.11.018

Cited by 4 publications

(16 citation statements)

References 32 publications

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“…The PDMS phantom has a relatively strong refractive index dependence on temperature as measured by its thermo-optic coefficient dn/dT ~ 4.5E-4 K −1 , which means good temperature sensitivity. The Matlab ® -based cross correlation algorithm PIVLAB2000 used in PIV flow studies [11, 14] was employed without modification to detect these apparent planar shifts in the particle positions between the US-exposed image and the pre-exposure (unheated) image. Sub-pixel displacements were accurately identified.…”

Section: Methodsmentioning

confidence: 99%

“…Cost and technical issues become important measurement concerns; including spatial and temporal resolutions, accuracy, and viscous heating in the case of invasive tools such as thermocouples [9]. Optical methods for thermometry [10] such as laser-induced fluorescence [11] and Raman scattering [12] hold good promise in meeting many of the technical challenges in pre-clinical laboratory testing. They provide high spatial and temporal resolutions, accuracy, and non-invasiveness, which is important in US applications.…”

Section: Introductionmentioning

confidence: 99%

“…The method bears resemblance to laser speckle thermometry described by Kihm [13] such as the underlying principle, which is light deflection due to thermo-optic refraction. The core of the novel method is the flow measurement technique particle image velocimetry (PIV), which uses a laser light sheet to illuminate passive particles seeded in a medium [11] as tracers. By taking image pairs of the tracers at short time delays, and cross correlating them, their 2-D particle displacement (velocity) vector map in the medium can be obtained.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion

Oweis

Dunmire

Cunitz

et al. 2015

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Transcutaneous focused ultrasound (US) is used to propel kidney stones using acoustic radiation force. It is important to estimate the level of heating generated at the stone/tissue interface for safety assessment. An in-vitro experiment is conducted to measure the temperature rise in a tissue-mimicking phantom with an embedded artificial stone and subjected to a focused beam from an imaging US array. A novel optical-imaging-based thermometry method is described using an optically clear tissue phantom. Measurements are compared to the output from a fine wire thermocouple placed on the stone surface. The optical method has good sensitivity, and it does not suffer from artificial viscous heating typically observed with invasive probes and thermocouples.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion

Oweis

Dunmire

Cunitz

et al. 2015

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

Self Cite

View full text Add to dashboard Cite

show abstract

“…Flow velocities induced in water by the same focused ultrasound transducer as used here were directly measured in water previously (Al-Qraini et al 2013) and were found to depend strongly on the focused ultrasound pulse duration. At the pulse duration of 100 µs and peak intensity of 14,000 W/cm 2 , the maximum observed flow speed was only 2 cm/s.…”

Section: Methodsmentioning

confidence: 62%

Pulsed Focused Ultrasound Treatment of Muscle Mitigates Paralysis-Induced Bone Loss in the Adjacent Bone: A Study in a Mouse Model

Poliachik¹,

Khokhlova²,

Wang³

et al. 2014

Ultrasound in Medicine & Biology

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Bone loss can result from bed rest, space flight, spinal cord injury or age-related hormonal changes. Current bone loss mitigation techniques include pharmaceutical interventions, exercise, pulsed ultrasound targeted to bone and whole body vibration. In this study, we attempted to mitigate paralysis-induced bone loss by applying focused ultrasound to the midbelly of a paralyzed muscle. We employed a mouse model of disuse that uses onabotulinumtoxinA-induced paralysis, which causes rapid bone loss in 5 d. A focused 2 MHz transducer applied pulsed exposures with pulse repetition frequency mimicking that of motor neuron firing during walking (80 Hz), standing (20 Hz), or the standard pulsed ultrasound frequency used in fracture healing (1 kHz). Exposures were applied daily to calf muscle for 4 consecutive d. Trabecular bone changes were characterized using micro-computed tomography. Our results indicated that application of certain focused pulsed ultrasound parameters was able to mitigate some of the paralysis-induced bone loss.

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“…But recently, HIFU has been used at elevated acoustic power intensities (3 ∼ 10 kW cm −2 ) in short bursts (µs − ms) for precision lesion formation [9] and tissue boiling and pulverization [10,11]. In such cases, the energy deposition region can be smaller than 1 mm across with heating rates on the order of O(10 4 • C s −1 ) [12]. A fast, resolved, and noninvasive thermometry tool that can elucidate the thermal behavior in such a scenario is of interest.…”

Section: Introductionmentioning

confidence: 99%

Laser ray bundle: a thermometry method for HIFU heating

Daoud¹,

Oweis²

2021

Meas. Sci. Technol.

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High-intensity focused ultrasound (HIFU) is a therapeutic modality that heats tissue by focusing a sound beam into a narrow, localized region. This paper is concerned with the thermo-optic lensing effect observed by Al-Qraini et al (Ultrasound Med. Biol. 39 647–59) when visible light was shone at a transparent tissue-mimicking phantom heated by HIFU. Thermal lensing was caused by light refraction as it passed through the thermal gradient region. HIFU thermal lensing was reproduced experimentally and studied analytically using the geometric (eikonal) ray equation to devise a method for temperature measurement. Under the Gaussian thermal field assumption, explicit closed form solutions were found for the forward thermo-optic ray deflection problem, and for the inverse opto-thermal conversion problem that yielded the underlying temperature field from measured ray deflections. Neither temperature calibration nor iterative computations were needed. In the experimental setup, a bundle of thin laser rays illuminated the HIFU-heated spot in a clear tissue-mimicking phantom. The ray deflections were recorded and directly converted into temperature with very good temporal and spatial resolution. These compared reasonably well against the output of an embedded thermocouple (TC)—considering the absorptive and viscous heating artifacts which were also investigated. The TC metallic tip junction was carefully positioned to coincide with the axis of peak heating. It was found that the TC stem (wire) transferred heat by conduction from the tip into the tissue located off the HIFU heating axis. The proposed thermometry method can be useful in elucidating heating from focused ultrasound sources, or from other sources of localized heating such as lasers.

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Laser-Induced Fluorescence Thermometry of Heating in Water from Short Bursts of High Intensity Focused Ultrasound

Cited by 4 publications

References 32 publications

Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion

Non-invasive measurement of the temperature rise in tissue surrounding a kidney stone subjected to ultrasonic propulsion

Pulsed Focused Ultrasound Treatment of Muscle Mitigates Paralysis-Induced Bone Loss in the Adjacent Bone: A Study in a Mouse Model

Laser ray bundle: a thermometry method for HIFU heating

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