The United States of America As Represented by the Department of Health

The United States of America

Joseph M Schmitt

Christopher Petroff

Joel M Friedman

Jay R Knutson

Elijah Charles Walker

Alexander Knuttel

Richard L Webber

An apparatus and method for using frequency modulated diffusive photon-density waves propagating through a turbid medium such as tissue for detecting optical properties of objects and for imaging objects within the turbid medium. Frequency modulation enables real time differential measurement of the interaction of different colors with the object when the different colors are chosen such that they react the same with the medium but differently with the object. The method greatly simplifies optical imaging and increases the amount of information which may be obtained about the object.

Method and apparatus for localization and spectroscopy of objects using

A non-invasive device which determines the pulp oxygenation level of a tooth and the vitality of a tooth using multiple-wavelength optical plethysmography. A sensor is shaped to be mounted on a tooth and circuitry for processing a signal from the sensor and supplied from a photosenstive diode is used. The photosensitive diode in the sensor detects light scattered from the tooth which was emitted from red, green, and infrared LEDs. An electrocardiogram (ECG) monitor is provided so as to produce improved detection reliability by synchronous averaging using the occurrence of the R-wave of the ECG as a time marker. Using this approach, a threshold-of-detection criterion can be established based on an average computed over a period to achieve a desired signal-to-noise ratio.

Pulse oximeter for diagnosis of dental pulp pathology

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Rockville, MD, United States of America

Joseph M Schmitt