Photoacoustic molecular imaging,combined with the reporter-gene technique,can provide a valuable tool for cancer research.The expression of the lacZ reporter gene can be imaged using photoacoustic imaging following th...Photoacoustic molecular imaging,combined with the reporter-gene technique,can provide a valuable tool for cancer research.The expression of the lacZ reporter gene can be imaged using photoacoustic imaging following the injection of X-gal,a colorimetric assay for the lacZ-encoded enzymeβ-galactosidase.Dual-wavelength photoacoustic microscopy was used to non-invasively image the detailed morphology of a lacZ-marked 9L gliosarcoma and its surrounding microvasculature simultaneously in vivo,with a superior resolution on the order of 10μm.Tumor-feeding vessels were found,and the expression level of lacZ in tumor was estimated.With future development of new absorption-enhancing reporter-gene systems,we anticipate this strategy can lead to a better understanding of the role of tumor metabolism in cancer initiation,progression,and metastasis,and in its response to therapy.展开更多
The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse c...The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to zero.This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries.For a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.展开更多
A reflection-mode photoacoustic microscope（PAM） for rat brain imaging in vivo is constructed.A pulsed laser is used as an excitation source,and a focused ultrasound transducer is adopted to collect the photoacoustic...A reflection-mode photoacoustic microscope（PAM） for rat brain imaging in vivo is constructed.A pulsed laser is used as an excitation source,and a focused ultrasound transducer is adopted to collect the photoacoustic signal.Raster scanning is applied to acquire three-dimensional（3D） data.The obtained measurements of the lateral and axial resolutions of the microscope are 45 and 15μm,respectively.The imaging depth in the chicken breast tissue is 3.1 mm at a signal-to-noise ratio（SNR） of 20 dB without any signal averaging.The imaging speed is 30 A-line/s.Experimental results in vivo demonstrate the capability of 3D imaging of the brain vessels of the rat after removing the skull.展开更多
基金funded in part by the NIH grants R01 NS46214(BRP)and R01 EB000712.
文摘Photoacoustic molecular imaging,combined with the reporter-gene technique,can provide a valuable tool for cancer research.The expression of the lacZ reporter gene can be imaged using photoacoustic imaging following the injection of X-gal,a colorimetric assay for the lacZ-encoded enzymeβ-galactosidase.Dual-wavelength photoacoustic microscopy was used to non-invasively image the detailed morphology of a lacZ-marked 9L gliosarcoma and its surrounding microvasculature simultaneously in vivo,with a superior resolution on the order of 10μm.Tumor-feeding vessels were found,and the expression level of lacZ in tumor was estimated.With future development of new absorption-enhancing reporter-gene systems,we anticipate this strategy can lead to a better understanding of the role of tumor metabolism in cancer initiation,progression,and metastasis,and in its response to therapy.
基金sponsored in part by National Institutes of Health Grant Nos.R01 EB000712 and R01 NS46214(BRP).
文摘The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused geometries.In the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to zero.This approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free boundaries.For a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.
基金supported by the National Natural Science Foundation of China(No.60828009)the Programme of Introducing Talents of Discipline to Universities (111 Project).
文摘A reflection-mode photoacoustic microscope（PAM） for rat brain imaging in vivo is constructed.A pulsed laser is used as an excitation source,and a focused ultrasound transducer is adopted to collect the photoacoustic signal.Raster scanning is applied to acquire three-dimensional（3D） data.The obtained measurements of the lateral and axial resolutions of the microscope are 45 and 15μm,respectively.The imaging depth in the chicken breast tissue is 3.1 mm at a signal-to-noise ratio（SNR） of 20 dB without any signal averaging.The imaging speed is 30 A-line/s.Experimental results in vivo demonstrate the capability of 3D imaging of the brain vessels of the rat after removing the skull.
