- Optical tomography
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Optical tomography Intervention MeSH D041622 Optical tomography is a form of computed tomography that creates a digital volumetric model of an object by reconstructing images made from light transmitted and scattered through an object.[1] Optical tomography is used mostly as a form of research in medical imaging.
Optical tomography relies on the object under study being at least partially light-transmitting or translucent, so it works best on soft tissues; imaging of breast and brain tissue are examples.
The high scatter-based attenuation involved is generally dealt with by using intense, often pulsed or intensity modulated, light sources, and highly sensitive light sensors, and the use of infrared light at frequencies where body tissues are most transmissive. Soft tissues are highly scattering but weakly absorbing in the near-infrared and red parts of the spectrum, so that this is the wavelength range usually used.
One recent variant of optical tomography uses optical time-of-flight sampling as an attempt to distinguish transmitted light from scattered light. This concept has been used in several academic and commercial systems for breast cancer imaging and cerebral measurement. The key to separation of absorption from scatter is the use of either time-resolved or frequency domain data which is then matched with a diffusion theory based estimate of how the light propagated through the tissue. The measurement of time of flight or frequency domain phase shift is essential to allow separation of absorption from scatter with reasonable accuracy.
A more recent development since about the year 2000, has been the development of systems for fluorescence tomography of tissue. In these systems, the fluorescence signal transmitted through the tissue is normalized by the excitation signal transmitted through the tissue, and so many of the fluorescence tomography systems do not require the use of time-resolved or frequency domain data, although research is still ongoing in this area. Since the applications of fluorescent molecules in humans are fairly limited, most of the work in fluorescence tomography has been in the realm of pre-clinical cancer research. Both commercial systems and academic research have been shown to be effective in tracking tumor protein expression and production, and tracking response to therapies.
Optical tomography found its application in industry as a sensor of thickness and internal structure of semiconductors [2].
See also
References
- ^ MeSH Optical+Tomography
- ^ ^ Wojtek J. Walecki and Fanny Szondy, "Integrated quantum efficiency, reflectance, topography and stress metrology for solar cell manufacturing", Sunrise Optical LLC, Proc. SPIE 7064, 70640A (2008); doi:10.1117/12.797541
External links
- Optical tomography at Imperial College, London
- Optical tomography at University College, London
- "Boobs, Babes and Blood" - Article on physics.org
MRI MRI of brain and brain stem · MR neurography · Cardiac MRI/Cardiac MRI perfusion · MR angiography · MR cholangiopancreatography · Breast MRI
Functional MRI · Diffusion MRIUltrasound Echocardiography / Doppler echocardiography (TTE · TEE) · Intravascular · Gynecologic · Obstetric · Echoencephalography · Transcranial doppler · Abdominal ultrasonography · Transrectal · Breast ultrasound · Transscrotal ultrasound · Carotid ultrasonography
Contrast-enhanced · 3D ultrasound · Endoscopic ultrasound · Emergency ultrasound (FAST) · DuplexRadionuclide 2D / scintigraphyCholescintigraphy · Scintimammography · Ventilation/perfusion scan · Radionuclide ventriculography · Radionuclide angiography · Radioisotope renography · Sestamibi parathyroid scintigraphy · Radioactive iodine uptake test · Bone scintigraphy · Immunoscintigraphy
full body: Octreotide scan · Gallium 67 scan · Indium 111 WBC scan3D / ECTSPECT (gamma ray): SPECT of brain, Myocardial perfusion imaging
PET (positron): Brain PET, Cardiac PET, PET mammography, PET-CTOptical laser Thermography Breast thermographyCategories:- Optical imaging
- Neuroimaging
- Science stubs
- Medical equipment stubs
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