Optical tomography of the breast using a 32-channel time-resolved imager

Hebden, Jeremy C.; Bland, Tara; Hillman, Elizabeth M. C.; Gibson, AP; Everdell, Nick; Delpy, David T.; Arridge, Simon R.; Douek, Michael

doi:10.1364/bio.2002.sue5

Cited by 5 publications

(8 citation statements)

References 13 publications

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“…Therefore our patient studies have been restricted to the use of single rings, which are mounted in an adjustable frame described in detail elsewhere. 18 The volunteer leans against the frame with either the left or the right breast placed in either of the two holes. The rings around the holes are of different diameters to accommodate various breast sizes.…”

Section: A Imaging Geometrymentioning

confidence: 99%

Monitoring recovery after laser surgery of the breast with optical tomography: a case study

Hebden¹,

Yates²,

Gibson³

et al. 2005

Appl. Opt.

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Results are presented of a study to monitor the changes in the optical properties of breast tissue over a 12-month period after interstitial laser photocoagulation treatment of a fibroadenoma. The study involved generating cross-sectional images of the breast with a multichannel time-resolved imaging system and a nonlinear image reconstruction algorithm. Images of the internal absorbing and scattering properties revealed the expected initial inflammatory response, followed by the development of low-scattering cysts consistent with corresponding ultrasound examinations. Although results indicate that purely qualitative images can potentially provide clinically valuable data, means of enhancing diagnostic information by overcoming present limitations of the approach are discussed.

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Section: A Imaging Geometrymentioning

confidence: 99%

Monitoring recovery after laser surgery of the breast with optical tomography: a case study

Hebden¹,

Yates²,

Gibson³

et al. 2005

Appl. Opt.

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“…) in the second term of the right hand side (rhs) of equation (7) gives the derivatives of the fluence at all mesh nodes for the previous time step. Therefore, the calculations of the Jacobian at a specific time step requires the calculation of the fluence derivatives for all mesh nodes for all previous time steps.…”

Section: Jacobian Calculationsmentioning

confidence: 99%

“…Instead, equation (7) can be solved iteratively using only the fluence rates at previous time steps and not the fluence derivatives, thereby reducing the memory storage requirements. By subsequent substitutions of the fluence derivatives of previous time steps into equation (7), the Jacobian is given by…”

Section: Jacobian Calculationsmentioning

confidence: 99%

“…scattering and absorption coefficients) [1][2][3]. The spatial distribution of the tissue optical properties may give insight into the tissue physiology and can be used in applications such as breast imaging [4][5][6][7][8], neonatal brain imaging [9][10][11], adult cortical brain imaging [11][12][13][14], and small animal imaging [15]. There are different systems for DOT based on different boundary measurement data acquisitions which can be divided into continuous wave (CW), frequency domain (FD), and time domain (TD) systems [16].…”

Section: Introductionmentioning

confidence: 99%

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Time-domain diffuse optical tomography using recursive direct method of calculating Jacobian at selected temporal points

Naser

Deen

2015

Biomed. Phys. Eng. Express

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An algorithm for time-domain diffuse optical tomography based on the resolution of the timedomain diffusion equation using the finite element method has been developed. An efficient direct method including a recursive approach has been used to obtain the light fluence derivatives with respect to tissue optical properties at precise selected points on the temporal profile resulting in a considerable savings in computation time and memory. The algorithm reconstructs the tissue optical properties in a permissible region or a region-of-interest and the input data for reconstruction comprises selections of points on the temporal curve of the measured pulse. The optical properties have been reconstructed by solving an iterative normalized minimization problem. The algorithm has been applied to a three-dimensional simplified model of a new born baby head and to a threedimensional model of the mouse (MOBY) for a small animal model. The computation speed and memory usage of the algorithm have been compared with that of other techniques based on continuous wave and frequency domain representations. The effects of using different sizes of time steps and number of time steps on the reconstruction accuracy and the computation time have been reported.

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“…The boundary measurements of the light fluence rates due to external excitation sources can be used to reconstruct the tissue optical properties (e.g. scattering and absorption coefficients) which may give insight into tissue physiology and can be used in applications such as breast imaging [4][5][6][7][8] and brain imaging [9][10][11][12][13][14]. Different data acquisition systems can be used for DOT including continuous wave (CW), frequency domain (FD), and time domain (TD) and in general the DOT problem is ill-posed and the solution is usually obtained through an iterative minimization problem [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Improving the reconstruction image contrast of time-domain diffuse optical tomography using high accuracy Jacobian matrix

Naser

2016

Biomed. Phys. Eng. Express

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An algorithm for time-domain diffuse optical tomography using a high accuracy Jacobian matrix has been developed. The Jacobian matrix has been calculated using a new direct method that uses two finite element meshes of different sizes. A low density mesh has been used for the inverse calculations where the tissue optical properties are reconstructed at its nodes' locations. The second mesh has a bigger size and is used to calculate the high accuracy light fluence rates and the Jacobian matrix. The high accuracy light fluence is interpolated to obtain its values at the nodes of the low density mesh and at the detectors' locations. The high accuracy Jacobian matrix at the nodes of the low density mesh are obtained by integrating the Jacobian calculated using the high density mesh. The integration of the Jacobian using the proposed method does not require calculating the Jacobian explicitly at all nodes of the high density mesh which is inefficient in memory requirement and computation speed. The improvement of the Jacobian accuracy while using a low density mesh for the inverse calculations improves the reconstructed image contrast and the computation speed. The optical properties are reconstructed in a region of interest by solving iteratively a self-regularized minimization problem. The minimization problem uses the calculated Jacobian and the light fluence at precisely selected points on the temporal profile of each source-detector pair for the reconstruction. The algorithm has been applied to a three-dimensional model of a neonatal brain and to a three-dimensional model of the mouse for a small animal model. The reconstruction results by the proposed method have been compared with the results using a single mesh for the Jacobian calculations. The effect of using different sizes of the low density mesh for the inverse calculations on the image contrast has been reported.

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Optical tomography of the breast using a 32-channel time-resolved imager

Cited by 5 publications

References 13 publications

Monitoring recovery after laser surgery of the breast with optical tomography: a case study

Monitoring recovery after laser surgery of the breast with optical tomography: a case study

Time-domain diffuse optical tomography using recursive direct method of calculating Jacobian at selected temporal points

Improving the reconstruction image contrast of time-domain diffuse optical tomography using high accuracy Jacobian matrix

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