Massachusetts Institute of Technology

Avco Everett Research Laboratory, Inc.

Jersey Nuclear-avco Isotopes, Inc.

Medical Laser Research and Development Corporation

Irving Itzkan

Michael S Feld

Lev T Perelman

Yang Wang

Vadim Backman

Jun Wu

Ramachandra Rac Dasari

George Zonios

Ramasamy Manoharan

Rajan Gurjar

Ramanchandra R Dasari

Richard P Rava

Michael E Mack

Robert T Kung

Charles T Pike

Richard G Morton

Gary B Hayes

Ramachandra Rao Dasari

Herbert P Kent

Douglas Albagli

Joseph A Izatt

James F Brennan, Iii

Andrew J Berger

Kaz Tanaka

Ramachandra Roa Dasari

The present invention relates to systems and methods for measuring one or more physical characteristics of material such as tissue using optical radiation. The system can use light that is scattered by a tissue layer to determine, for example, the size of nuclei in the tissue layer to aid in the characterization of the tissue. These methods can include the use of fiber optic devices to deliver and collect light from a tissue region of interest to diagnose, for example, whether the tissue is normal or precancerous.

Method for measuring tissue morphology

The present invention relates to the use of polarized light to measure properties of tissue. More particularly, polarized light can be used to detect dysplasia in tissue as the polarization of back-scattered light from such tissues is preserved while the contribution of diffusely scattered light from underlying tissues can be removed. A fiber optic system for delivery and collection of light can be used to measure tissues within the human body.

Polarized light scattering spectroscopy of tissue

The present invention relates to the use of polarized light to measure properties of tissue. More particularly, polarized light can be used to detect dysplasia in tissue as the polarization of backscattered light from such tissues is preserved while the contribution of diffusely scattered light from underlying tissues can be removed. A fiber optic system for delivery and collection of light can be used to measure tissues within the human body.

The present invention relates to the use of time gated scattered light, for determining the location and composition of material within various organs of the human body. The systems and methods of the present invention provide for medical imaging in three dimensions of internal body structures for diagnostic purposes.

Optical imaging using time gated scattered light

Measuring tissue morphology

The present invention relates to the use of inelastically scattered light, particularly fluorescent and Raman scattered light, for determining the location and composition of material within various organs of the human body. The systems and methods of the present invention provide for medical imaging in three dimensions as well as histological information that can be used for diagnosing disease and various medical conditions.

Optical imaging of tissue using inelastically scattered light

The present invention relates to systems of methods of measuring selected analytes in blood and tissue using Raman spectroscopy to aid in diagnosis. More particularly, Raman spectra are collected and analyzed to measure the concentration of dissolved gases and other analytes of interest in blood. Methods include in vivo transdermal and continuous monitoring as well as in vitro blood analysis.

Apparatus and methods of raman spectroscopy for analysis of blood gases

Removal of body tissue with a long pulsed lasers is achieved such that sufficient energy to remove tissue is transmitted to the desired body without damaging an optical fiber transmitting the laser radiation. Pairs of pulses having the same or different wavelengths are coupled to more effectively remove tissue from the surgical site.

Pulsed laser system for the surgical removal of tissue

A hand piece for use with a laser includes a scanning mechanism which controls dosimetry of radiation applied to a target area which is adjustable to limit thermal diffusion from the light absorbing portion of the irradiated target site for selective target specific energy deposition. When used for dermatologic purposes, the adjustable scanning mechanism permits radiation to impinge on tissue for a predetermined period of time for the selective necrosis of highly-filled blood vessels, while leaving adjacent tissue and empty blood vessels undamaged. The dwell time of the laser beam is designed to match the diffusion time for thermal destruction of the wall of the abnormal vessel, with the dwell time adjusted by the scanning rate.

Laser system for providing target specific energy deposition and damage

A method for laser melting of silicon for the production of boules pulled from a pool of liquid ultraclean or ultrapure silicon wherein the boules are used for producing silicon wafers suitable for use in the electronics field. A laser beam, preferably P polarized, is directed at an angle of about 88 degrees to the normal to the surface of silicon disposed in conventional melting apparatus. A suitable mirror is preferably provided to capture and reflect that portion of the laser beam reflected from the surface of the pool. Use of the present invention permits continuous operation by adding solid silicon and melting it at the point of impingement of the laser beam with up to about 96% absorption of laser energy at this point, thereby permitting the provision of heat in a very controlled manner in a continuous ultraclean silicon crystal growth process.

Method for laser melting of silicon

For use in a pulsed-laser lidar such as a laser ceilometer, there are shown several examples of signal processing means for separating desired pulses due to targets such as clouds from strong background signals due to suspended particles causing poor visibility. The several examples belong to a class of means having the property of applying, to an electrical signal pulse waveform, a time-distributed signed electrical weighting function having negligible total weight, with alternations of sign of weights separated by intervals of the order of the width of the desired pulses.

Laser ceilometer signal processing means

A tunable alkali metallic vapor laser system is disclosed. Stimulated Raman scattering (SRS) in a low pressure atomic alkali metallic vapor of potassium or cesium is utilized wherein the atomic vapor is provided and then primed to populate an intermediate level such as the 4P.sub.1/2 level for potassium and the 6P.sub.1/2 level for cesium from which the desired upper laser level is accessible. After the population is created at the intermediate level, it is pumped to a virtual level near the desired upper laser level by a tunable dye laser and, via the SRS process, generates the tunable output laser beam.

Tunable alkali metallic vapor laser

A system for stabilizing the frequency of a laser employing the variation in position of interference patterns which results from a variation in laser beam frequency in passing through a Fabry Perot etalon filter. The system is particularly useful for maintaining strict frequency control at a particular frequency in the output of a tunable laser such as a dye laser for use in isotope separation.

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Boston, MA, United States of America

Irving Itzkan