UWB Microwave Imaging System with A Novel Calibration Approach For Breast Cancer Detection

Abstract

An apparatus and method for imaging a tissue. The method includes transmitting a first microwave frequency signal to and receiving a first total signal from the tissue at a first position. A second microwave frequency signal is transmitted to and a second total signal received from the tissue at a second position. The first total signal is calibrated with respect to the second total signal and an image is constructed from the calibrated signal.

What is claimed is: 
     
         1 . A method of imaging a tissue, the method comprising:
 transmitting a first microwave frequency signal to the tissue at a first position;   receiving a first total signal reflected from the tissue at the first position;   transmitting a second microwave frequency signal to the tissue at a second position;   receiving a second total signal reflected from the tissue at the second position;   calibrating the first total signal with the respect to the second total signal; and   constructing an image of the tissue from the calibrated signal.   
     
     
         2 . The method of  claim 1 , wherein the second position is radially-spaced away from the first position by an angle that ranges from about 0.5 degrees to about 5 degrees. 
     
     
         3 . The method of  claim 1 , wherein the second position is linearly-spaced away from the first position by a distance that ranges from about 1 mm to about 20 mm. 
     
     
         4 . The method of  claim 1 , wherein the tissue comprises a glandular soft tissue and includes at least one mass located therein. 
     
     
         5 . The method of  claim 4 , wherein the first and total signals each include a first portion having reflections due to a tissue-air interface, a second portion having reflections due to a transmitter-receiver coupling, a third portion having reflections due to the at least one mass, and a fourth portion having reflections due to multiple scatterings. 
     
     
         6 . The method of  claim 1 , wherein transmitting each of the first and second total signals further comprises:
 generating an alternating signal;   mixing the alternating signal with an oscillating clock signal;   amplifying the mixed signal at a high-gain amplifier; and   transmitting the amplified, mixed signal to a transmitting antenna.   
     
     
         7 . The method of  claim 1 , wherein receiving each of the first and second total signals further comprises:
 amplifying received first and second total signals at a low-noise amplifier;   down-converting the amplified signal into two channels;   mixing the down-converted signal of each of the two channels with an oscillating clock signal; and   converting the mixed signal from each of the two channels to a respective digital signal.   
     
     
         8 . The method of  claim 1 , wherein calibrating the first total signal includes subtracting the second total signal from the first total signal. 
     
     
         9 . The method of  claim 1 , wherein constructing the image further comprises:
 applying a delay and sum algorithm to the calibrated first signal.   
     
     
         10 . The method of  claim 1 , wherein a first transducer transmits the first microwave frequency signal and receives the first total signal and a second transducer transmits the second microwave frequency signal and receives the second total signal. 
     
     
         11 . The method of  claim 1 , wherein a transducer transmits the first microwave frequency signal and receives the first total signal at the first position and is then moved to the second position for transmitting the second microwave frequency signal and receiving the second total signal. 
     
     
         12 . A medical imaging device comprising:
 a tissue support having a size and shape to receive a tissue;   at least one transducer operably coupled to the tissue support, the at least one transducer having a transmitting antenna and a receiving antenna, the transmitting antenna operable in a frequency range of about 2 GHz to about 8 GHz and the receiving antenna operable in a frequency range of about 2 GHz to about 8 GHz; and   wherein the at least one transducer transmits a first signal and receives a first total signal at a first position with respect to the tissue and transmits a second signal and receives a second total signal at a second position with respect to the tissue.   
     
     
         13 . The medical imaging device of  claim 12 , wherein the tissue support is a breast imaging cup. 
     
     
         14 . The medical imaging device of  claim 13 , wherein the breast imaging cup is operably coupled to a brassiere. 
     
     
         15 . The medical imaging device of  claim 14  further comprising:
 a track operably coupled to the tissue support, the at least one transducer moveable along the track between the first position and the second position. 
 
     
     
         16 . The medical imaging device of  claim 12  wherein the transmitting antenna and the receiving antenna are the same antenna. 
     
     
         17 . A medical imaging device comprising:
 a tissue support having a size and shape to receive a tissue;   a plurality of transducers operably coupled to the tissue support, each of the plurality of transducers having a transmitting antenna and a receiving antenna, the transmitting antenna operable in a frequency range of about 2 GHz to about 8 GHz and the receiving antenna operable in a frequency range of about 2 GHz to about 8 GHz, wherein a select one of the plurality of transducers transmits a first signal and receives a first total signal and an adjacent one of the plurality of transducers transmits a second signal and receives a second total signal.   
     
     
         18 . The medical imaging device of  claim 17 , wherein each of the plurality of transducers is radially-spaced away from an adjacent one of the plurality of transducers by an angle that ranges from about 0.5 degrees to about 5 degrees. 
     
     
         19 . The medical imaging device of  claim 17 , wherein each of the plurality of transducers is linearly-spaced away from an adjacent one of the plurality of transducers by a distance that ranges from about 1 mm to about 20 mm. 
     
     
         20 . The medical imaging device of  claim 17  further comprising:
 a controller configured to calculate a calibrated signal by subtracting the second total signal from the first total signal. 
 
     
     
         21 . The medical imaging device of  claim 20 , wherein the controller is further configured to construct an image of the tissue from the calibrated signal. 
     
     
         22 . The medical imaging device of  claim 17 , wherein the tissue support is a breast imaging cup. 
     
     
         23 . The medical imaging device of  claim 22 , wherein the breast imaging cup is operably coupled to a brassiere. 
     
     
         24 . The medical imaging device of  claim 17 , wherein the medical imaging device is part of an imaging system that includes a support configured to support the at least one medical imaging device in an anatomical arrangement suitable for imaging a tissue of a patient. 
     
     
         25 . The medical imaging device of  claim 24 , wherein the imaging system further includes:
 a second tissue support having a size and shape to receive a tissue;   a second plurality of transducers operably coupled to the second tissue support, each of the second plurality of transducers having a transmitting antenna and a receiving antenna, the transmitting antenna operable in a frequency range of about 2 GHz to about 8 GHz and the receiving antenna operable in a frequency range of about 2 GHz to about 8 GHz,   wherein a select one of the second plurality of transducers transmits a third signal and receives a third total signal and an adjacent one of the second plurality of transducers transmits a fourth signal and receives a fourth total signal, and   each of the tissue supports is a breast imaging cup, one of the tissue cups being configured to receive a left breast and the tissue cup being configured to receive a right breast.   
     
     
         26 . The medical imaging device of  claim 17  wherein the transmitting antenna and the receiving antenna are the same antenna. 
     
     
         27 . A method of reconstructing an image a tissue from first and second microwave signals, the method comprising:
 receiving the first microwave signal reflected from the tissue at a first position;   receiving the second microwave signal reflected from the tissue at a second position;   calibrating the first microwave signal with the respect to the second microwave signal; and   constructing an image of the tissue from the calibrated signal.   
     
     
         28 . A method of scanning a tissue, the method comprising:
 transmitting a first microwave frequency signal to the tissue at a first position;   receiving a first total signal reflected from the tissue at the first position;   transmitting a second microwave frequency signal to the tissue at a second position; and   receiving a second total signal reflected from the tissue at the second position, wherein, the first and second positions are separated by less than about 20 mm.