We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its ...We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth.OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules.However,given the inadequate absoption of some biomolcules,detection sensitivity at the same incident intensity requires improvement.In this study,a modulated continuous wave with power density less than 3mW/cm^(2)(1/4 of the ANSI safety limit)excited the weak photoacoustic(PA)signals of biological cells.A microcavity traneducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid;air pressure variation is inversely proportional to cavity volume at the same temperature increase.Considering that a PA wave expands in various directions,detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio.Therefore,we employ four detectors to acquire tiny PA signals simul-taneously.Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.展开更多
Optical-resolution photoacoustic microscopy(OR-PAM)has been developed for anatomical,functional,and molecular imaging but usually requires multiple scanning for different contrasts.We present five-wavelength OR-PAM fo...Optical-resolution photoacoustic microscopy(OR-PAM)has been developed for anatomical,functional,and molecular imaging but usually requires multiple scanning for different contrasts.We present five-wavelength OR-PAM for simultaneous imaging of hemoglobin concentration,oxygen saturation,blood flow speed,and lymphatic vessels in single raster scanning.We develop a five-wavelength pulsed laser via stimulated Raman scattering.The five pulsed wavelengths,i.e.,532,545,558,570,and 620∕640 nm,are temporally separated by several hundreds of nanoseconds via different optical delays in fiber.Five photoacoustic images at these wavelengths are simultaneously acquired in a single scanning.The 532-and 620∕640-nm wavelengths are used to image the blood vessels and dye-labeled lymphatic vessels.The blood flow speed is measured by a dual-pulse method.The oxygen saturation is calculated and compensated for by the Grüneisen-relaxation effect.In vivo imaging of hemoglobin concentration,oxygen saturation,blood flow speed,and lymphatic vessels is demonstrated in preclinical applications of cancer detection,lymphatic clearance monitoring,and functional brain imaging.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61178086)Science and Technology Program of Guangzhou,China(Grant No.2012J4300138)Foundation for Distinguished Young Talents in South China Normal University,China.(Grant No.2012KJ010).
文摘We demonstrate the feasibility of simultancous multi-probe detection for an optcal-resolution photoacoustic microscopy(OR-PAM)system.OR-P AM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth.OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules.However,given the inadequate absoption of some biomolcules,detection sensitivity at the same incident intensity requires improvement.In this study,a modulated continuous wave with power density less than 3mW/cm^(2)(1/4 of the ANSI safety limit)excited the weak photoacoustic(PA)signals of biological cells.A microcavity traneducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid;air pressure variation is inversely proportional to cavity volume at the same temperature increase.Considering that a PA wave expands in various directions,detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio.Therefore,we employ four detectors to acquire tiny PA signals simul-taneously.Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.
基金This work was partially supported by the National Natural Science Foundation of China(NSFC)(Nos.81627805 , 61805102)Research Grants Council of the Hong Kong Special Administrative Region(Nos.21205016,11215817, 11101618)Shenzhen Basic Research Project(No.JCYJ20170413140519030).
文摘Optical-resolution photoacoustic microscopy(OR-PAM)has been developed for anatomical,functional,and molecular imaging but usually requires multiple scanning for different contrasts.We present five-wavelength OR-PAM for simultaneous imaging of hemoglobin concentration,oxygen saturation,blood flow speed,and lymphatic vessels in single raster scanning.We develop a five-wavelength pulsed laser via stimulated Raman scattering.The five pulsed wavelengths,i.e.,532,545,558,570,and 620∕640 nm,are temporally separated by several hundreds of nanoseconds via different optical delays in fiber.Five photoacoustic images at these wavelengths are simultaneously acquired in a single scanning.The 532-and 620∕640-nm wavelengths are used to image the blood vessels and dye-labeled lymphatic vessels.The blood flow speed is measured by a dual-pulse method.The oxygen saturation is calculated and compensated for by the Grüneisen-relaxation effect.In vivo imaging of hemoglobin concentration,oxygen saturation,blood flow speed,and lymphatic vessels is demonstrated in preclinical applications of cancer detection,lymphatic clearance monitoring,and functional brain imaging.
