Download Optical coherence tomography (OCT) is a technique that can obtain

FUNDING PROGRAM FOR NEXT GENERATION WORLD-LEADING RESEARCHERS
Project Title: Real-time optical coherence tomography using ultrafast and ultrabroad fiber sources for medical applications
Name: Shinji YAMASHITA
Institution: The University of Tokyo
1. Background of research
Optical coherence tomography (OCT) is a technique that can obtain tomographic images of living organs. OCT
features high-resolution, safety, small size and low cost. It has been already widely used by ophthalmologists.
Further improvement in imaging speed is required for wider medical applications.
applications
2. Research objectives
This project
Thi
j t aims
i
att development
d
l
t off real-time
l ti
OCT systems
t
using
i our original
i i l ultra-fast
lt f t and
d ultra-broad
lt b d fiber
fib
light sources, and their medical applications.
3 Research
3.
R
h characteristics
h
t i ti (incl.
(i l originality
i i lit and
d creativity)
ti it )
We have two original light sources, one is the ultra-fast and ultra-broad tunable fiber laser based on dispersion
tuning, and the other is the nano-carbon-based ultra-broad band white source. The former is the tunable laser
whose tuning
g speed
p
is faster byy a few tens of times than the existing
g tunable lasers,, and the latter is the ultrabroad fiber supercontinuum (SC) source generated by a low-cost and stable ultra-fast pulse laser using carbon
nanotube (CNT) or graphene.
4. Anticipated effects and future applications of research
We expect realization of ultra-fast and ultra-high resolution OCT system that could not be achieved with existing
light sources, and medical applications to the area where very fast imaging is essential, such as intravascular
or visceral
i
l imaging
i
i in
i conjunction
j
ti with
ith the
th catheters
th t
or endoscopes.
d
W also
We
l expectt the
th life
lif innovation
i
ti in
i terms
t
of wide spread of low-cost and ubiquitous OCT systems.
Background of research: Optical coherence tomography (OCT)
X-rayy CT,, MRI
☺ Can image whole body
Slow, LowLow-resolution, Large, Costly 10mm
☺ Small,
S ll L
Low-cost
Low-
Sl
Slow,
L
Low-resolution,
Lowl i
Sh
Shallow
ll
iimage
Optical coherence tomography (OCT)
Resolu
ution
MRI
Ultrasonic CT
1mm
X-rayy CT
10μm
E l ti off OCT
Evolution
Swept Source
(SS)OCT
A Scan
Delay=0
Ultrasonic CT
100μm
☺ High
High--resolution, Fast, Small, Low
Low--cost
Very shallow image 1μm
Principle: Interference between ref. and scattered lights from sample.
Objects： Skin, Teeth, Eye/Fundus, Viscera, Vascula, etc.
Time Domain
（TD
TD）
）OCT Reference Arm
Thickness of
human body
OCT
1mm
10mm
100mm
10cm
Imaging depth
Spectral
Domain
(SD)OCT
Delay=0
ΔL1
ΔL1
Sample Arm
Swept Source
Low Coherence
Source
Sample
Low Coherence Source
Sample
B Scan
λ
Grating
Photo Detector
PC（FFT）
1st -generation: Moving parts for A-scan, slow
Research objectives
1D-CCD
2nd-generation: No moving parts for A-scan, ultra-fast and ultra-high-resolution
2nd gen. OCT performance depends on quality of light sources
This p
project
j
aims at development
p
of real-time SS/SD-OCT systems
y
using
g ultra-fast
and ultra-broad fiber sources based on our original mode-locking techniques, and
their medical applications.
Research characteristics
1. Ultra
Ultra--fast dispersiondispersion-tuned fiber lasers
No mechanical scanning
Ultra-broad band （~200nm）, Ultra-high
p
（>100kHz）） scanning
（
g
speed
Applicable to any kind of lasers at any
wavelength
Isolator
Gain
medium
Coupler
Dispersive
element
Laser output
RF
synthesizer
fm
Controller
t
Dispersion-tuned fiber laser
Ultra-broad band tuning spectra
10mm laser cavity
2 Nano
2.
Nano--carbon ultra
ultra--fast pulsed lasers
Passively mode-locked lasers using
saturable absorption in CNT/graphene
can generate very stable short pulse （<100fs
） with a very simple construction
Applicable to wide wavelength range
Ultra-broad band and low-noise fiber
supercontinuum (SC) generation
Future
F t
applications
li ti
off research
h
High-performance and lowHighlow-cost OCT system
g the newly
y developed
p light
g sources
using
Medical applications：
applications：Ultra
Ultra--high resolution
3D/4D retinal, intravascular or visceral imaging
Pump light
HR mirrors
Graphene
p
Carbon nanotube ((CNT))
10GHz mode-locked spectrum
Esophagus
p g
Brain
Kostadinka Bizheva, et al.,
J. of Biomedical Optics,
July/ 2004 Vol.9 No.4
Courtesy of Tsukuba Univ.
Petra Wilder-Smith, et al.
J. of Biomedical Optics Sep/ 2005 Vol.10 No.5
Tooth
Cardiovascular
Pancreas
Pier Alberto, et al.
J Pancreas (Online)
2007 Vol.8 No.2
Yonghong He, et al.
J. of Biomedical Optics
Jan/ 2004 Vol.9 No.1
Lung
Guillermo J. Tearney, et al.
J. of Biomedical Optics
Mar/ 2006 Vol.11 No.2
Kidney
Z.P.Chen, et al.,
Opt. Express, Aug/ 2007
Vol. 15 No. 16
Alexander Popp, et al.,
J. of Biomedical Optics, Jan/ 2004
Vol.11 No.1
Cervix
Trachea
Matthew Brenner, et al.,
J. of Biomedical Optics,
Sep/ 2007 Vol.12 No.5
Cochlea
Fangyi Chen, et al.,
J. of Biomedical Optics,
Mar/ 2007 Vol.12 No.2
Colon
Stomach
Bladder
Versatile and ubiquitous OCT system for not
only medical but also industrial applications
Ultra-broad band SC generation
Eye
ye
Oral
World’ss smallest CNT mode-locked laser
World
Yu Chen, et al.
J. of Biomedical Optics
Sep/ 2007 Vol.12 No.3
Skin
Ying T. Pan, et al.
J. of Biomedical Optics
Sep/ 2007 Vol.12 No.5
Ilya V. Turchin, et al.,
J. of Biomedical Optics,
Nov/ 2005 Vol.10 No.6
Blood flow
Alexandre R. Tumlinson, et al.,
J. of Biomedical Optics,
Nov/ 2006 Vol.11 No.6
Bradley A. Bower., J. of Biomedical Optics,
Jul/ 2007 Vol.12 No.4
Bone