Apparatus and method for noninvasive doppler ultrasound-guided real-time control of tissue damage in thermal therapy
First Claim
1. A method for ultrasonic Doppler monitoring of the extent and geometry of damage to a tissue resulting from treatment with a thermal modality, comprising the steps of:
- providing an echo-Doppler transmitter/receiver coupled to a transducer;
treating a tissue with a thermal modality;
emitting ultrasonic waves from said transducer toward the region of a tissue receiving thermal treatment;
receiving echoes from the thermally treated tissue;
converting the echoes to electrical echo signals, said echo signals each containing a phase vector indicating motion and echogenicity in the tissue relative to the transducer at a plurality of tissue depths;
deriving x and y components of the phase vector of each echo signal as functions of range and time;
outputting pairs of in-phase and quadrature-phase (I and Q) Doppler signals; and
evaluating said I and Q Doppler signals to determine the extent and geometry of tissue damage resulting from said thermal treatment.
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Accused Products
Abstract
A method and apparatus for noninvasive and real-time monitoring and feedback control of the extent and geometry of tissue damage induced by various thermal modalities (laser, electromagnetic wave, ultrasound and thermistor) in different thermal therapies (hyperthermia, thermal coagulation and ablation) is provided. Unlike the existing ultrasound configurations, which use non-Doppler ultrasound techniques, the single-beam configuration in this invention employs a multiple-range-gate pulsed Doppler technique. The configuration may be operated in A-mode, M-mode, or multi-dimensional image mode to monitor tissue thermal response in the tissue being treated at multiple tissue depths along the sound beam. By measuring changes in phase (i.e., motion) and amplitude (i.e., echogenicity) of the echoes returned from the tissue under treatment, the Doppler system can determine temporal and spatial profiles of tissue temperature and the extent and geometry of tissue thermal damage. The system can also differentiate tissue responses corresponding to coagulation of tissue (in hyperthermia or coagulation treatment) versus ablation of tissue. Further, the Doppler detection provides feedback signals using fuzzy logic technology to automatically and in real-time regulate thermal output of various thermal modalities so that optimal thermal treatment can be obtained. The control of thermal output is achieved by adjusting treatment parameters such as pulse rate, exposure time and output power in the case of lasers. The Doppler detection results can also be shown on a suitable display device to allow manual feedback control of a thermal modality by a human operator.
643 Citations
11 Claims
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1. A method for ultrasonic Doppler monitoring of the extent and geometry of damage to a tissue resulting from treatment with a thermal modality, comprising the steps of:
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providing an echo-Doppler transmitter/receiver coupled to a transducer; treating a tissue with a thermal modality; emitting ultrasonic waves from said transducer toward the region of a tissue receiving thermal treatment; receiving echoes from the thermally treated tissue; converting the echoes to electrical echo signals, said echo signals each containing a phase vector indicating motion and echogenicity in the tissue relative to the transducer at a plurality of tissue depths; deriving x and y components of the phase vector of each echo signal as functions of range and time; outputting pairs of in-phase and quadrature-phase (I and Q) Doppler signals; and evaluating said I and Q Doppler signals to determine the extent and geometry of tissue damage resulting from said thermal treatment. - View Dependent Claims (2, 3, 4)
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5. Apparatus for ultrasonic Doppler monitoring of the extent and geometry of damage due to thermal treatment of a living tissue, comprising:
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a thermal modality for applying thermal treatment to a living tissue; an echo-Doppler transmitter/receiver for emitting ultrasonic waves toward the region of said living tissue receiving thermal treatment, for receiving echoes from the treated tissue, and for converting the echoes to electrical signals, said electrical signals each containing a phase vector indicating motion and echogenicity in the tissue relative to the transducer at a plurality of tissue depths; echo-signal processing means coupled to said echo-Doppler transmitter/receiver for deriving x and y components of the phase vector of each echo signal as functions of range and time and for outputting multiple pairs of I and Q Doppler signals; and evaluating means coupled to said echo-signal processing means for determining the extent and geometry of tissue damage resulting from said thermal treatment. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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Specification