Breaking the acoustic diffraction limit via nonlinear effect and thermal confinement for potential deep-tissue high-resolution imaging

Yuan, Baohong; Pei, Yanbo; Kandukuri, Jayanth

doi:10.1063/1.4792736

Cited by 14 publications

(17 citation statements)

References 11 publications

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“…4 [20]. A high-intensity focused ultrasound (HIFU) transducer can be used to externally and rapidly increase the temperature of the tissue above the threshold temperature to switch on the fluorophores (due to tissue absorption of acoustic energy) [17, 18] . After ultrasound exposure, the thermal energy is diffused quickly and the temperature recovers to background temperature.…”

Section: Principle Of Usf Imagingmentioning

confidence: 99%

“…When adopting fluorophore-labeled thermosensitive polymers or nanoparticles, the spatial resolution can be further improved based on two unique mechanisms, as has been demonstrated recently [17, 18]. (1) When a nonlinear acoustic effect occurs, both lateral and axial acoustic and thermal focal sizes are dramatically reduced below the diffraction-limited size.…”

Section: Principle Of Usf Imagingmentioning

confidence: 99%

“…(1) When a nonlinear acoustic effect occurs, both lateral and axial acoustic and thermal focal sizes are dramatically reduced below the diffraction-limited size. This means the spatial resolution of the USF technique can be higher than the ultrasound and PA techniques when using the same ultrasound frequency [18]. (2) Unlike ultrasound and PA techniques, the spatial resolution of the USF technique depends on the size of the region where the fluorophores can be switched on [17].…”

Section: Principle Of Usf Imagingmentioning

confidence: 99%

“…Recently, we proposed and developed a fundamentally different technique, ultrasound-switchable fluorescence (USF) imaging [17–19]. It has been demonstrated that the USF-based imaging technique has potential to break the acoustic diffraction limit and to reach a relatively higher spatial resolution compared with similar ultrasound and photoacoustic techniques [17, 18]. In this work, a general introduction to the USF imaging principle is given in Section II.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Development of Ultrasound-Switchable Fluorescence Imaging Contrast Agents Based on Thermosensitive Polymers and Nanoparticles

Cheng

Wei

Liu

et al. 2014

IEEE J. Select. Topics Quantum Electron.

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In this work we first introduced a recently developed high-resolution, deep-tissue imaging technique, ultrasound-switchable fluorescence (USF). The imaging principles based on two types of USF contrast agents were reviewed. To improve USF imaging techniques further, excellent USF contrast agents were developed based on high-performance thermoresponsive polymers and environment-sensitive fluorophores. Herein, such contrast agents were synthesized and characterized with five key parameters: (1) peak excitation and emission wavelengths (λex and λem), (2) the fluorescence intensity ratio between on and off states (IOn/IOff), (3) the fluorescence lifetime ratio between on and off states (τOn/τOff), (4) the temperature threshold to switch on fluorophores (Tth), and (5) the temperature transition bandwidth (TBW). We mainly investigated fluorescence intensity and lifetime changes of four environment-sensitive dyes [7-(2-Aminoethylamino)-N,N-dimethyl-4-benzofurazansulfonamide (DBD-ED), St633, Sq660, and St700] as a function of temperature, while the dye was attached to poly(N-isopropylacrylamide) linear polymers or encapsulated in nanoparticles. Six fluorescence resonance energy transfer systems were invented in which both the donor (DBD-ED or ST425) and the acceptor (Sq660) were adopted. Our results indicate that three Förster resonance energy transfer systems, where both IOn/IOff and τOn/τOff are larger than 2.5, are promising for application in future surface tissue bioimaging by USF technique.

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Section: Principle Of Usf Imagingmentioning

confidence: 99%

Section: Principle Of Usf Imagingmentioning

confidence: 99%

Section: Principle Of Usf Imagingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Development of Ultrasound-Switchable Fluorescence Imaging Contrast Agents Based on Thermosensitive Polymers and Nanoparticles

Cheng

Wei

Liu

et al. 2014

IEEE J. Select. Topics Quantum Electron.

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“…Recently, focused ultrasound has been used in combination with fluorescence tomography, not to modulate the optical signal, but to modulate the temperature of the medium has been used in combination with temperature sensitive contrast agents to improve the spatial resolution and quantitative accuracy [21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Validation of temperature-modulated fluorescence tomographyin vivo

et al. 2014

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To overcome the strong scattering in biological tissue that has long afflicted fluorescence tomography, we have developed a novel technique, "temperature-modulated fluorescence tomography" (TM-FT) to combine the sensitivity of fluorescence imaging with focused ultrasound resolution. TM-FT relies on two key elements: temperature sensitive ICG loaded pluronic nanocapsules we termed ThermoDots and high intensity focused ultrasound (HIFU). TM-FT localizes the position of the fluorescent ThermoDots by irradiating and scanning a HIFU beam across the tissue while conventional fluorescence tomography measurements are acquired. The HIFU beam produces a local hot spot, in which the temperature suddenly increases changing the quantum efficiency of the ThermoDots. The small size of the focal spot (~1 mm) up to a depth of 6 cm, allows imaging the distribution of these temperature sensitive agents with not only high spatial resolution but also high quantitative accuracy in deep tissue using a proper image reconstruction algorithm. Previously we have demonstrated this technique with a phantom study with ThermoDots sensitive in the20-25°C range. We recently optimized the ThermoDots for physiological temperatures. In this work, we will demonstrate a new HIFU scanning method which is optimized for in vivo studies. The performance of the system is tested using a phantom that resembles a small animal bearing a small tumor targeted by ThermoDots.

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In vivo ultrasound-switchable fluorescence imaging

Yao

Liu

et al. 2019

Sci Rep

Self Cite

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The conventional fluorescence imaging has limited spatial resolution in centimeter-deep tissue because of the tissue’s high scattering property. Ultrasound-switchable fluorescence (USF) imaging, a new imaging technique, was recently proposed to realize high-resolution fluorescence imaging in centimeter-deep tissue. However, in vivo USF imaging has not been achieved so far because of the lack of stable near-infrared contrast agents in a biological environment and the lack of data about their biodistributions. In this study, for the first time, we achieved in vivo USF imaging successfully in mice with high resolution. USF imaging in porcine heart tissue and mouse breast tumor via local injections were studied and demonstrated. In vivo and ex vivo USF imaging of the mouse spleen via intravenous injections was also successfully achieved. The results showed that the USF contrast agent adopted in this study was very stable in a biological environment, and it was mainly accumulated into the spleen of the mice. By comparing the results of CT imaging and the results of USF imaging, the accuracy of USF imaging was proved.

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Breaking the acoustic diffraction limit via nonlinear effect and thermal confinement for potential deep-tissue high-resolution imaging

Cited by 14 publications

References 11 publications

Development of Ultrasound-Switchable Fluorescence Imaging Contrast Agents Based on Thermosensitive Polymers and Nanoparticles

Development of Ultrasound-Switchable Fluorescence Imaging Contrast Agents Based on Thermosensitive Polymers and Nanoparticles

Validation of temperature-modulated fluorescence tomographyin vivo

In vivo ultrasound-switchable fluorescence imaging

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