二维形状基扩散光学成像的实验研究

135 浏览量更新于2024-08-27 收藏 218KB PDF 举报

"An experimental investigation on two-dimensional shape-based diffuse optical tomography" 本文主要探讨了一种用于弥散光学成像（Diffuse Optical Tomography, DOT）的二维（2D）形状基础的图像重建方法，该方法利用边界元素法进行实现。弥散光学成像是一种无创、非侵入性的成像技术，主要用于研究生物组织内部的光学性质，如血液流量和氧气饱和度等。在实验验证部分，研究团队使用了一个四通道时间关联单光子计数（Time-Correlated Single Photon Counting, TCSPC）系统进行检测，并采用强度数据类型进行图像重建。TCSPC技术能够精确测量光子到达时间分布，这对于评估光在生物组织中的传播路径至关重要。通过结合强度数据，可以获取关于组织光学性质和几何结构的信息。文章提出了一种差分成像方案，该方案允许同时恢复光学参数和几何参数。这种方法的独特之处在于它将形状信息与边界元素法相结合，提高了重建图像的精度和可靠性。边界元素法是一种数值计算方法，常用于求解偏微分方程，例如在光学成像中解决反问题时。实验结果显示，所提出的2D形状基础DOT模态展现出对体内光学结构重建的潜力。文中提到的OCIS代码（Optical Society of America的分类标识）170.3880、170.6960、170.3010和170.3660分别对应于光学成像系统、生物医学光学成像、光学成像技术和光学成像的特定领域。这一研究工作不仅为弥散光学成像提供了一种新的、有效的图像重建策略，还为生物医学检测技术与仪器的发展带来了新思路。通过改进和优化这种形状基础的方法，未来可能在临床诊断和疾病监测等方面有更广泛的应用。同时，这也为光学成像技术的理论研究和实际应用开辟了新的道路。

August 10, 2010 / Vol. 8, No. 8 / CHINESE OPTICS LETTERS 787

An experimental investigation on two-dimensional

shape-based diﬀuse optical tomography

Pingqiao Ruan (



)

, Feng Gao (



)

1,2∗

, Fang Yang (



ǱǱǱ

)

, and Huijuan Zhao (



)

1,2

College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China

Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin 300072, China

∗

E-mail: gaofeng@tju.edu.cn

Received January 26, 2010

A two-dimensional (2D) shape-based approach of image reconstruction using a boundary element method

is developed for diﬀuse optical tomography (DOT). The experimental validation uses a four-channel time-

correlated single photon counting (TCSPC) system for detection and an intensity data-type for image

reconstruction. The optical and geometric parameters are simultaneously recovered using a diﬀerence

imaging scheme. Results demonstrate that the proposed DOT modality is a promising methodology of in

vivo reconstruction of the optical structures of tissues.

OCIS co des: 170.3880, 170.6960, 170.3010, 170.3660.

doi: 10.3788/COL20100808.0787.

Fluorescence molecular tomography (FMT) is a novel op-

tical imaging modality for visualizing the biochemical

events located deep inside intact living organisms with

molecule-speciﬁc ﬂuorescent agent

[1]

. Researchers have

demonstrated that knowledge on optical properties distri-

bution in tissues signiﬁcantly aﬀects FMT

[2]

.Toprovide

optical priors for enhanced ﬂuorescence reconstruction,

a combination of FMT and diﬀuse optical tomography

(DOT) is desirable.

DOT is a noninvasive medical imaging technology that

probes internal optical properties and can provide both

anatomical images and functional information of tissues.

However, due to the strong scattering nature of most tis-

sue types and relatively limited number of available noisy

data, image reconstruction in conventional voxel-based

DOT has been a severely ill-posed inverse problem

[3]

One way of improving this situation is to take advantage

of prior information on the probability distribution of ex-

pected parameters based on anatomical structures

[4,5]

The use of the anatomical structures has allowed for

the reasonable postulation of the unknown body as being

composed of a number of sub-domains of diﬀerent tissues,

and the interior optical parameter values as a piecewise

constant. In this case, we can parameterize the unknowns

of the inverse problem directly in terms of a small number

of parameters describing the shape, location, and optical

properties of each region. Since unknown boundaries are

typically modeled with some parametric shape functions,

the image reconstruction can thus be cast as a shape-

based DOT issue in order to simultaneously recover the

boundary-describing parameters and optical properties

of disjoint domains

[6]

With the recent advancement of DOT, the shape-based

image reconstruction schemes have also been proposed.

The use of boundary element method (BEM) for shape-

based imaging in DOT has been reported

[4]

.Inthat

work, the authors recovered the shape and optical prop-

erties of an inclusion from simulated DOT data using

an alteration strategy and based on the assumption that

background values are known and exact. In this let-

ter, a two-dimensional (2D) shape-based reconstruction

scheme for steady-state DOT is validated by a cylindrical

phantom. A diﬀerence imaging scheme is used to handle

noisy measurement data, as well as to achieve more ac-

curate parameter estimation. The optical coeﬃcients of

the background are assumed as unknown and recovered

in the reconstruction.

The diﬀusion approximation (DA) with Robin bound-

ary condition has been frequently used in the modeling of

light propagation for biological tissues

[4]

. Based on the

assumption on multi-domain geometries, Ω = ∪

=1



which are separated by smooth interfaces Γ



( =

2, ··· ,L), and with the piecewise constant optical prop-

erties, the steady-state formulation of the diﬀusion ap-

proximation was equivalent to a set of coupled Helmholtz

equations

[7]

∇



(r)−k



(r)=−



(r)



, r ∈ Ω



,=1, 2, ··· ,L (1)

with boundary conditions

−1

=Φ



,κ

-1

ˆn ·∇Φ

−1

= κ



ˆn ·∇Φ



on Γ



cΦ

+2κ

1+R

1 − R

ˆn ·∇Φ

=0 on ∂Ω, (2)

where Φ



(r) is the photon density; q



(r) denotes an inte-

rior isotropic source density in domain ;thewavenum-

bers k



associated with the Helmholtz equation in each

domain has the form of k



= μ

a

c/κ



, c is the speed of

light in the medium, μ

a

, μ



s

,andκ



= c/[3μ



s

]arethe

absorption, reduced scattering, and diﬀusion coeﬃcients,

respectively; ˆn denotes unit normal vector outward to the

boundary; and R

is an internal reﬂection factor that ac-

counts for the diﬀerence in the refractive indices between

the two sides of the most outer boundary, ∂Ω.

If the closed interfaces Γ



are suﬃciently smooth, they

can be approximated by the Fourier curve. With the

shape coeﬃcients γ



= {γ



,γ



} for the boundaries of

each inner domain deﬁned, the parametric description of

the curve was represented by the weighted average de-

1671-7694/2010/080787-04

 2010 Chinese Optics Letters

下载后可阅读完整内容，剩余3页未读，立即下载

weixin_38747233

粉丝: 8
资源: 969

二维形状基扩散光学成像的实验研究

Theoretical and experimental study on two-dimensional binary locally resonant phononic crystals

A two-dimensional hybrid for elastic-plastic stress analysis

Experimental investigation on bit-rate-adaptive software synchronous optical sampling

Experimental investigation on Q-switching and Q-switched mode-locking operation in gold nanorods-based erbium-doped fiber laser

Experimental investigation on pulse-contrast degradation caused by surface reflection in optical parametric chirped-pulse amplification

Experimental investigation on laser-induced surface damage threshold of Nd-doped phosphate glass

Efficient background removal based on two-dimensional notch filtering for polarization interference imaging spectrometers

Experimental validation for time-domain fluorescence diffuse optical tomography of linear scheme

Experimental validation of domain-level gradient-based and hierarchical PCE-based routing and control in heterogeneous optical networks

Experimental research on application of Hartmann micro-lens array in coherent beam combination of two-dimensional laser array

最新资源