Frequency domain optical imaging using diffusion of intensity modulated radiation
First Claim
1. A method for producing images based upon diffusion of intensity modulated radiation and frequency domain analysis comprising:
- a. illuminating a medium with light radiation which is amplitude modulated;
b. detecting amplitude modulated diffusional radiation from the medium at a plurality of detection locations forming a detection area, including detecting the phase of the amplitude modulated diffusional radiation at each detection location, and detecting the demodulation of the amplitude modulated diffusional radiation at each detection location; and
c. displaying an image of the medium comprised of data from the detected relative phase or demodulation of the amplitude modulated diffusional radiation at each detection location.
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Accused Products
Abstract
Arrangements are disclosed for producing images based upon diffusional wave theory and frequency domain analysis. A medium to be imaged is illuminated with amplitude modulated radiation, and diffusional radiation transmitted or reflected by the medium is detected at a plurality of detection locations, as by a television camera. The phase and also the amplitude demodulation of the amplitude modulated diffusional radiation is detected at each detection location. A relative phase image and also a demodulation amplitude image of the medium are then generated from respectively the detected relative phase values and the detected demodulation amplitudes of the diffusional radiation at the plurality of locations. The present invention is particularly suited for medical applications for generating images of internal anatomical details of the body by using a near infrared amplitude modulated source for illumination of the body. In such medical applications, the body is illuminated with near infrared radiation having a wavelength between 600 and 1200 nanometers which is amplitude modulated at a frequency in the megahertz to gegihertz range, and internal images of the patient are generated for medical diagnosis. In preferred embodiments, a laser is utilized to generate the near infrared radiation near or below a 10 watt power level which is coupled by fiber optic cables to the body of the patient. Detection is also with fiber optic cables placed in direct contact with an opposed surface of the body which couple the transmitted diffusional radiation to an image intensifier placed in front of a television camera detector. The gain of the image intensifier is modulated at a frequency to obtain a heterodyned output frequency of less than 60 hertz which is within the detection bandwidth of the television camera.
193 Citations
36 Claims
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1. A method for producing images based upon diffusion of intensity modulated radiation and frequency domain analysis comprising:
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a. illuminating a medium with light radiation which is amplitude modulated; b. detecting amplitude modulated diffusional radiation from the medium at a plurality of detection locations forming a detection area, including detecting the phase of the amplitude modulated diffusional radiation at each detection location, and detecting the demodulation of the amplitude modulated diffusional radiation at each detection location; and c. displaying an image of the medium comprised of data from the detected relative phase or demodulation of the amplitude modulated diffusional radiation at each detection location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for producing images based upon diffusion of intensity modulated radiation and frequency domain analysis comprising:
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a. means for illuminating a medium with light radiation which is amplitude modulated; b. means for detecting amplitude modulated diffusional radiation from the medium at a plurality of detection locations forming a detection area, including means for detecting the phase of the amplitude modulated diffusional radiation at each detection location, and means for detecting the demodulation of the amplitude modulated diffusional radiation at each detection location; and c. means for displaying an image of the medium comprised of data from the detected relative phase or demodulation of the amplitude modulated diffusional radiation at each detection location. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification