Chrono-coherent imaging for medicine

Spears, Kenneth G.; Serafin, Jenifer; Abramson, Nils H.; Zhu, Xinming; Bjelkhagen, Hans I.

doi:10.1109/10.42116

Cited by 118 publications

(22 citation statements)

References 46 publications

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“…The phase delay, 0 (in radians), between the source and the detector may be expressed as P Pd O(p) = 2ir-= 2ir-= 2lTrf P Aw T VW' [1] where Aw is the wavelength, Td is the transport delay, T is the period of the sinusoidal wave, and f is the frequency of the wave.…”

Section: Theorymentioning

confidence: 99%

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Highly sensitive object location in tissue models with linear in-phase and anti-phase multi-element optical arrays in one and two dimensions.

Chance

Kang

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

114

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Based upon previous observations of lowfrequency photon diffusion waves within highly scattering tissue, this paper explores the "near-field" phenomena of such waves of 10-cm wavelength with 200-MHz phase modulation equipment. Multiple-element source arrays consist of laser diode sources modulated at 1800 out of phase with respect to the other sources. The diffusing waves originating from the outof-phase sources give, in the midplane, an amplitude null and a sharp phase transition. These may be observed in a highly scattering intralipid medium simulating the breast or brain (0.5% intralipid), 3-5 cm from the transmitting laser diodes.In the plane containing the array, there is a high sensitivity for a small volume of a hidden absorber (indocyanine green) deep within a highly scattering medium; 20 pmol in a volume of 70 ,ul can be detected. Two-dimensional arrays consisting of four or more elements in two orthogonal planes give sensitivity on both axes similar to the one-dimensional array. Measurements show that in the presence of a light-absorbing object, the amplitude null and the interference plane becomes a curved surface which is deflected toward the heterogeneity. The degree of deflection is related to the volume and the absorption characteristics of the heterogeneity and provides detection of the heterogeneity, and thereby may provide localization information for the detection of small tumors within the human breast, or stroke volumes, aneurysms, and tumors in the human brain.

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Section: Theorymentioning

confidence: 99%

“…The apparently simplest method is that of ballistic or snake imaging, where the scattered rays are discarded and only those whose pathlength approximates the geometric input/output distance are accepted (1)(2)(3)(4)(5). Selection of these pathways is achieved by time gating or phased coherence at the optical frequency.…”

mentioning

confidence: 99%

Highly sensitive object location in tissue models with linear in-phase and anti-phase multi-element optical arrays in one and two dimensions.

Chance

Kang

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

114

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“…In these methods coherently backscattered or transmitted light is made to interfere with the delayed light from the source. If a light source with a short coherence length is used then this can lead to very high spatial resolution (Spears et al, 1989;Huang et al, 1991;Leith et aI., 1991) technique is limited to a depth in tissue of at most I mm, and is therefore not suitable for the sort of applications considered here.…”

Section: Possible Approaches To Optical Imagingmentioning

confidence: 97%

2-D Optical Tomography for Medical Applications

Zee¹,

Roy²,

Khalaf³

et al. 1998

Nondestructive Testing and Evaluation

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Optical spectroscopy techniques are frequently used to non-invasively monitor various physiological functions such as tissue and blood oxygenation. It is desirable to develop methods to localise these measurements and quantify the parameters of interest, e.g. oxygen saturation. There is also a need for the localisation of abnormal tissues using non-harmful radiation, for example localisation and characterisation of breast tumours. This is possible in principle, provided the optical properties of abnormal tissues are sufficiently different. To establish a baseline reference, against which more advanced optical imaging systems and methods can be compared, a rotate-translate optical imaging system was developed. Image reconstruction was performed using a conventional filtered back projection scheme, originally developed for CT. With this system the limits of spatial and contrast resolution as a function of the absorption and reduced scattering coefficient were investigated. The limiting factor was found to be contrast resolution. Given the often small differences in the absorption and scattering properties of different tissues this makes such a system of limited use. A second generation imaging system, using a rotate-rotate type scanning system, has been constructed. Data obtained with this system utilises all the light emerging in the plane of measurement, and does not assume rectilinear propagation. The image reconstruction algorithm developed for this uses diffusion theory to model the light transport, and an iterative reconstruction algorithm. Results obtained with this model are presented. A further method to improve image quality is the use of a phase resolved technique", which uses amplitude modulation of the light source. An outline is given of the principle of this technique, and the system designed for the measurement is discussed.

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“…Stetson first showed the principle of coherence gating for imaging through a foglike medium [1]. In 1989, light-inflight holography was demonstrated, exploiting the finite coherence length of the light source to facilitate the depth-resolved imaging of 3D objects [2]. However, photographic film was used as the holographic recording media.…”

Section: Introductionmentioning

confidence: 99%

Fourier-domain digital holographic optical coherence imaging of living tissue

2007

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Digital holographic optical coherence imaging is a full-frame coherence-gated imaging approach that uses a CCD camera to record and reconstruct digital holograms from living tissue. Recording digital holograms at the optical Fourier plane has advantages for diffuse targets compared with Fresnel off-axis digital holography. A digital hologram captured at the Fourier plane requires only a 2D fast Fourier transform for numerical reconstruction. We have applied this technique for the depth-resolved imaging of rat osteogenic tumor multicellular spheroids and acquired cross-section images of the anterior segment and the retinal region of a mouse eye. A penetration depth of 1.4 mm for the tumor spheroids was achieved.

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Chrono-coherent imaging for medicine

Cited by 118 publications

References 46 publications

Highly sensitive object location in tissue models with linear in-phase and anti-phase multi-element optical arrays in one and two dimensions.

Highly sensitive object location in tissue models with linear in-phase and anti-phase multi-element optical arrays in one and two dimensions.

2-D Optical Tomography for Medical Applications

Fourier-domain digital holographic optical coherence imaging of living tissue

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