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Photoacoustic temperature imaging based on multi-wavelength excitation
摘要： Building further upon the high spatial resolution offered by ultrasonic imaging and the high optical contrast yielded by laser excitation of photoacoustic imaging, and exploiting the temperature dependence of photoacoustic signal amplitudes, this paper addresses the question whether the rich information given by multispectral optoacoustic tomography (MSOT) allows to obtain 3D temperature images. Numerical simulations and experimental results are reported on agarose phantoms containing gold nanoparticles and the effects of shadowing, reconstruction flaws, etc. on the accuracy are determined.
关键词： photoacoustic imaging,absorption coefficient,finite difference,multispectral optoacoustic tomography
更新于2025-11-14 15:30:11
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A Nanoprobe for Diagnosing and Mapping Lymphatic Metastasis of Tumor Using 3D Multispectral Optoacoustic Tomography Owing to Aggregation/Deaggregation Induced Spectral Change
摘要： Lymphatic metastasis of tumor is one of leading causes of cancer-related death, and diagnosing lymphatic metastasis is of significance in terms of optimal disease management and possible better outcomes for patients. Herein a turn-on optoacoustic nanoprobe is reported for noninvasively diagnosing and locating lymphatic metastasis in vivo. A positively charged tricyanofuran-containing polyene chromophore (TCHM) with high extinction coefficient is designed, synthesized, and allowed to form the nanoprobe with a negatively charged hyaluronan. The TCHMs take an aggregated state within the nanoprobe and exhibit weak absorption at 882 nm, the overexpressed hyaluronidase in cancer cells specifically degrades hyaluronan into small fragments and disaggregates TCHMs, thereby greatly enhancing the absorption at 882 nm and generating prominent optoacoustic signals. For multispectral optoacoustic tomography (MSOT) imaging in vivo, mice models with subcutaneous tumor and orthotopic bladder tumor are imaged first to demonstrate the nanoprobe’s capability for detecting HAase-overexpressing tumors. A mouse model of lymphatic metastasis of tumor is then established and the lymphatic metastasis is successfully imaged and tracked optoacoustically. The imaging results were verified using multiple biochemical assays. Moreover, 3D MSOT renderings are obtained for precisely locating and tracking the metastasis of tumor in lymphatic system in a spatiotemporal manner.
关键词： lymphatic metastasis,imaging,multispectral,nanoprobe,3D,optoacoustic tomography,aggregation
更新于2025-09-23 15:23:52
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Multispectral optoacoustic tomography (MSOT) for imaging the particle size-dependent intratumoral distribution of polymeric micelles
摘要： Purpose: This study proposes the utilization of multispectral optoacoustic tomography (MSOT) to investigate the intratumoral distribution of polymeric micelles and effect of size on the biodistribution and antitumor efficacy (ATE). Materials and methods: Docetaxel and/or optoacoustic agent-loaded polymeric micelles (with diameters of 22, 48, and 124 nm) were prepared using amphiphilic block copolymers poly (ethylene glycol) methyl ether-block-poly (D,L lactide) (PEG2000–PDLLAx). Subcutaneous 4T1 tumor-bearing mice were monitored with MSOT imaging and IVIS? Spectrum in vivo live imaging after tail vein injection of micelles. The in vivo results and ex vivo confocal imaging results were then compared. Next, ATE of the three micelles was found and compared. Results: We found that MSOT imaging offers spatiotemporal and quantitative information on intratumoral distribution of micelles in living animals. All the polymeric micelles rapidly extravasated into tumor site after intravenous injection, but only the 22-nm micelle preferred to distribute into the inner tumor tissues, leading to a superior ATE than that of 48- and 124-nm micelles. Conclusion: This study demonstrated that MSOT is theranostically a powerful imaging modality, offering quantitative information on size-dependent spatiotemporal distribution patterns after the extravasation of nanomedicine from tumor blood vessels.
关键词： intratumoral distribution,MSOT,multispectral optoacoustic tomography,in vivo imaging,tumor model,particle size,polymeric micelle
更新于2025-09-23 15:23:52
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Four-dimensional optoacoustic monitoring of tissue heating with medium intensity focused ultrasound
摘要： Medium-intensity focused ultrasound (MIFU) concerns therapeutic ultrasound interventions aimed at stimulating physiological mechanisms to reinforce healing responses without reaching temperatures that can cause permanent tissue damage. The therapeutic outcome is strongly affected by the temperature distribution in the treated region and its accurate monitoring represents an unmet clinical need. In this work, we investigate on the capacities of four-dimensional optoacoustic tomography to monitor tissue heating with MIFU. Calibration experiments in a tissue-mimicking phantom have confirmed that the optoacoustically-estimated temperature variations accurately match the simultaneously acquired thermocouple readings. The performance of the suggested approach in real tissues was further shown with bovine muscle samples. Volumetric temperature maps were rendered in real time, allowing for dynamic monitoring of the ultrasound focal region, estimation of the peak temperature and the size of the heat-affected volume.
关键词： photoacoustic imaging,thermal treatment monitoring,therapeutic ultrasound,temperature monitoring,optoacoustic tomography
更新于2025-09-10 09:29:36