PHOTOACOUSTIC MICROSCOPY SYSTEM
COMPANY PROFILE
MicroPhotoAcoustics, Inc. (MPA)—a spin-off from Advanced Optowave Coporation—was
founded in 2010 with the inventors of three-dimensional photoacoustic microscopy. Multiple
patents have been licensed from Dr. Lihong Wang’s lab, Optical Imaging Laboratory at
Washington University in St. Louis. MPA provides commerical photoacoustic microscopy (PAM)
systems at both optical resolution (OR-PAM) and acoustic resolution (AR-PAM) worldwide.
TECHNOLOGY OVERVIEW
Photoacoustic microscopy is the fastest growing biomedical imaging technology, which affords
high-resolution sensing of rich optical contrast in vivo at super-depths—depths beyond the optical
transport mean free path (~1 mm in the skin). Although commercially available high-resolution
three-dimensional optical imaging modalities—including confocal microscopy, two-photon
microscopy and optical coherence tomography—have fundamentally impacted biomedicine,
none can reach super-depths in tissue. In PAM, short-pulsed laser light is absorbed by biological
tissue and converted to transient heating, which is subsequently converted into an ultrasonic
wave due to thermoelastic expansion. Detection of the ultrasonic wave yields a tomographic
image. Taking advantage of low ultrasonic scattering, PAM equivalently improves tissue optical
transparency by a factor of 1000 and consequently enables super-depth penetration at high
resolution. As a unique feature, PAM is exquisitely sensitive to optical absorption, most sensitive
among all imaging modalities. PAM enables in vivo imaging of the smallest blood vessels (i.e.,
capillaries) and single cells with intrinsic tissue contrast (i.e., no exogenous contrast agent
injected into the tissue). Both functional and molecular imaging based on optical contrast have
been achieved by PAM.
Copyright ©2011 MicroPhotoAcoustics, Inc.
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Comparison of Optical Microscopy Technologies
Imaging Capability
Confocal
Microscopy
Two-photon
Microscopy
Optical
Coherence
Tomography
Photoacoustic
Microscopy
1 mm
1 mm by OR-PAM
3 mm by AR-PAM
(50 MHz)
Fluorescence,
Fluorescence
scattering
Scattering,
polarization
Absorption
Resolution
~Depth/200
~Depth/100
~Depth/100
~Depth/100
Multiscale imaging
N
N
N
Y
Sensitivity to absorption
Low (6%)
None
Low (0.4%)
High (100%)
Doppler sensing
N
N
Y
Y
Speckle artifact
N
N
Y
N
Oxygen saturation of
hemoglobin
N
N
N (poor
sensitivity)
Y
Intrinsic-contrast melanin
imaging
N
N
N
Y
Molecular imaging
Y
Y
N (poor
sensitivity)
Y
Reporter gene imaging
Y
Y
N
Y
Imaging of metabolic rate of
oxygen
N
N
N
Y
Depth
0.2 mm
Contrast
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0.5 mm
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SYSTEM LAYOUT
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APPLICATIONS
1)
High resolution μm lateralresolution)
brain
500 µm
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2)
Capillary and single red blood cell
500 µm
Capillary bed
50 µm
RBC
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3)
Oxygenation saturation. Structural and functional microvascular imaging of a nude
mouse ear in vivo by OR-PAM. pper
nm;
right: vessel-by-vessel oxygenation saturation (sO2) mapping based on dual-wavelength measurements. The arteries and veins can be identified based on the sO2 map.
A1, a representative arteriole; V1, a representative venule; lower: whole ear sO2 map.
1
sO2
100 µm
0.4
1
sO2
500 µm
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4)
Contrast agents. Intravital PAM of amyloid plaques with Congo Red Dye.
Fluorescence
TPM
100 µm
OR-PAM
100 µm
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5)
Label-free PAM of ocular microvasculature in vivo.
200 µm
(µm)
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6)
Tumor angiogenesis monitoring.Longitudinalmonitoring
mediated neovascularization ina mouse
.
Non-transgenic mouse
Transgenic HIF mouse
d0
d3
Stage 1: Development
d1
d14
d60
Stage 2: Maintenance
d30
500 µm
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7)
Human finger cuticle.
500 µm
200 µm
Low
sO2
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High
sO2
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Transverse blood flow. Simultaneous photoacoustic imaging of oxygen saturation
and blood flow. (a) MAP of structural image. (b) MAP of oxygen saturation image
measured by two wavelengths 560 nm and 570 nm. (c) Blood flow image measured
by the Doppler bandwidth broadening. The flow direction was determined by a
bidirectional motor scanning. (d) The vascular traces with the oxygen saturation,
averaged along the segments of the vessels. (e) The vascular traces with the blood
flow velocity, in millimeters per second, averaged along the segments of the vessels.
(f) The transverse velocity profile of the blood flow indicated by the dashed line in (c). Scale bar = 250 μm.
Optical absorption
(d)
Min
(a)
Max
8)
1.0
Oxygen saturation
(b)
(e)
0.9
0.8
0.7
0.6
(f)
0
-2
-4
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velocity (mm/s)
2.
Flow velocity (mm/s)
(c)
4
4
2
0
-2
-4
-6
0200400600800
1000
Position (µm)
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9) Monitoring of melanoma
th
.(a)PAM
in the ear acquired before injection of melanoma cells. (b) PAM image where in vivo
red blood cells (RBCs) can be identified (the close-up image indicates the biconcave
structure of RBCs). (c) PAM image of blood vessels and melanoma taken four days
after injecting melanoma cells. The melanoma image is extracted by taking the
difference of the two PAM images [(a) and (c)] and is plotted in gray: MT, melanoma
tumor. (d) Optical microscopy image (0.057 NA) of the same area in (a) and (c).
a)
b)
200 µm
20 µm
5 µm
RBC
c)
d)
MT
Vasculature
m
a
x
m
i
n
Melanoma
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10) Image of
25 µm
PAM image of section without staining.
Section thickness: 6 µm.
25 µm
Optical micrograph (20X, 0.45 N.A.) of the
section stained by hematoxylin and eosin.
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TECHNICAL SPECIFICATIONS
In vivo imaging at tissue depths up to 1.2 mm
OR-PAM Systems
Lateral resolution down to 5 µm
Axial resolution down to 15 µm
Integrated, KHz tunable laser
In vivo imaging at tissue depths up to 3 mm
AR-PAM Systems
Axial resolution down to 15 µm
Lateral resolution down to 45 µm
Integrated, KHz tunable laser
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MicroPhotoAcoustics Inc
113 Comac Street
Ronkonkoma, NY 11779, USA
Tel :1-631-974-6268,
Fax:1-631-389-2554
Web: www.biompa.com
MicroPhotoAcoustics Inc. follows a policy of continuous product improvement. Specifications are subject to change without notice.
MicroPhotoAcoustics Inc offers a limited warranty for its products. For full details on warranty coverage, or for further product information,
please contact MicroPhotoAcoustics Inc.
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