Optical coherence tomography

Optical coherence tomography (OCT) is nowadays a rapidly developing tool for optical imaging of superficial areas (up to 1 mm) of tissue in vivo and in vitro. The capability to image scattering media with high spatial and time resolution makes this modality very attractive for scientists and clinicians in different fields.

Beside the capabilities for high-quality imaging, the slope of the OCT signal (A-scan) carries information about the light-attenuating properties of the medium under study. In its most basic form, quantitative OCT measurements are based on the single scattering model. In this model, the OCT attenuation coefficient is equal to the sum of the scattering and absorption coefficients. OCT can detect local changes of light scattering properties of the sample, for example, induced by glucose in blood and tissue.

OCT image of a finger pad. Sweat glands are clerly visible (helix-shaped channels).

OCT image of a nail fold. The nail is located on the left.


We employ OCT modality to perform imaging of biotissues and phantoms and glucose sensing.
 
Spectral-domain OCT for ophthalmic imaging

The development of spectral domain optical coherence tomography (SD-OCT) with 1-mm probing band has been continued. This work has been performed in collaboration with Computational Optics Group (COG) from University of Tsukuba, Japan. The imaging speed of SD-OCT system has improved to be 47 000 depth scans/sec. The spectrometer of that system is also modified to achieve better signal to noise ratio (SNR). In addition to system development, some data processing methods have been implemented, including Doppler signal based blood flow velocity determination method and retinal and choroidal vessel structure characterization method with artifact compensation. Several patient measurements have been performed to evaluate our systems suitability to diagnose ophthalmic diseases.

 
3D image of capillaries filled with 4% Intralipid embedded in a transparent medium. Dimensions (X : Y : Z) – (1.65 : 1 : 1.61) mm.
 


SLD-OCT images of mouse embryo: vertical axis: 1.54 mm (optical width), horizontal axis: 2.2. mm.

 


Glucose sensing in blood with SLD-OCT.

References

A. Popov, A. Bykov, S. Toppari, M. Kinnunen, A. Priezzhev, R. Myllylä, "Glucose sensing in flowing blood and Intralipid by laser pulse time-of-flight and optical coherence tomography techniques", IEEE J. Select. Topics Quant. Electron.18 (4), 1335-1342 (2012). DOI 10.1109/JSTQE.2011.2175202. [PDF]

A.V. Bykov, A.P. Popov, M. Kinnunen, T. Prykäri, A.V. Priezzhev, R. Myllylä, “Skin phantoms with realistic vessel structure for OCT measurements”, Proc. SPIE 7376, 73760F (2010). [PDF]

T. Fabritius, S. Makita, M. Miura, R. Myllylä, Y. Yasuno, "Automated segmentation of the macula by optical coherence tomography", J. Biomed. Opt. 14(1), 010503 (2009). [PDF]

T. Fabritius, S. Makita, Y. Yasuno, R. Myllylä, Y. Hong, "Automated retinal shadow compensation of optical coherence tomography images", Opt. Express 17(18), 15659-15669 (2009). [PDF]

S. Makita, T. Fabritius, Y. Yasuno, "Full-range, high-speed, high-resolution 1-um spectral-domain coherence tomography using BM-scan for volumetric imaging of the human posterior eye", Opt. Express 16(12), 8406-8420 (2008). [PDF]

S. Makita, T. Fabritius, Y. Yasuno, "Quantitative retinal-blood flow measurement with three-dimensional vessel geometry determination using ultrahigh-resolution Doppler optical coherence angiography", Opt. Express 33(8), 836-838 (2008). [PDF]

M. Kinnunen, R. Myllylä, S. Vainio, “Detecting glucose-induced changes in in vitro and in vivo experiments with optical coherence tomography,” J. Biomed. Opt. 13(2), 021111 (2008). [PDF]

M. Kinnunen, R. Myllylä, T. Jokela, S. Vainio, "In vitro studies toward noninvasive glucose monitoring with optical coherence tomography," Appl. Opt. 45, 2251-2260 (2006). [PDF]

Last updated: 9.9.2016