US 2010/0249570 A1 · THREE-DIMENSIONAL PHOTOACOUSTIC IMAGER AND METHODS FOR CALIBRATING AN IMAGER

Abstract

A photoacoustic imaging apparatus is provided for medical or other imaging applications and also a method for calibrating this apparatus. The apparatus employs a sparse array of transducer elements and a reconstruction algorithm. Spatial calibration maps of the sparse array are used to optimize the reconstruction algorithm. The apparatus includes a laser producing a pulsed laser beam to illuminate a subject for imaging and generate photoacoustic waves. The transducers are fixedly mounted on a holder so as to form the sparse array. A photoacoustic (PA) waves are received by each transducer. The resultant analog signals from each transducer are amplified, filtered, and converted to digital signals in parallel by a data acquisition system which is operatively connected to a computer. The computer receives the digital signals and processes the digital signals by the algorithm based on iterative forward projection and back-projection in order to provide the image.

Claims26

Dependent claims

Apparatus for photoacoustic (PA) imaging of a subject, said apparatus comprising:

a holder supporting said subject;
means for illuminating said subject by means of a beam capable of generating PA waves;
a staring sparse array of transducers for receiving said PA waves and converting said PA waves to corresponding analog signals, said sparse array having at least three transducers and having at least two dimensions, at least some of said transducers being spaced apart from one another in order to provide a wider range of viewing angles of said subject compared to viewing angles achievable with an equivalent number of closely spaced transducers;
a supporting structure for mounting said sparse array;
means for acoustically coupling said sparse array to said subject;
electronic means for receiving said analog signals, processing said analog signals, and converting said analog signals to corresponding digital signals;
and
a programmed computer system operatively connected to said electronic means to receive said digital signals and to process said digital signals by an image reconstruction algorithm to create one or more three dimensional (3-D) images of said subject.

5 more elements

A method for calibrating an apparatus for photoacoustic (PA) imaging of a subject, said apparatus including a staring sparse array of transducers for receiving PA waves from said subject and converting said PA waves to corresponding analog signals, said sparse array having at least three transducers and having at least two dimensions, at least some of the transducers being spaced apart from one another in order to provide a wider range of viewing angles of said subject compared to viewing angles of said subject compared to viewing angles achievable with an equivalent number of closely spaced transducers, supporting structure for mounting said sparse array, means for acoustically coupling said transducers of said array to said subject, electronic means for receiving, processing and converting said analog signals to provide corresponding digital signals, and a programmed computer system operatively connected to said electronic means to receive and process said digital signals,

said method comprising:
(a) providing a point source and means for illuminating said point source by means of a pulsed beam, said point source being capable of generating PA waves upon illumination by said beam and being located in said means for acoustically coupling;
(b) raster scanning said point source through a calibration volume so that said point source is scanned to and stopped at a plurality of grid points in a predetermined timed manner;
(c) simultaneously operating said illuminating means so as to produce said beam and transmitting a pulse of said beam to said point source at each of said grid points, thereby generating said PA waves from the point source at each of said grid points;
(d) detecting said PA waves from said point source at each of said grid points by means of each of said transducers and converting said PA waves to corresponding analog signals;
and
(e) generating three-dimensional (3-D) characterization maps from said digital signals by means of said electronic means and said computer system.

4 more elements

Dependencies are inferred from the claim text.

Three-dimensional photoacoustic imager and methods for calibrating an imager

Life of this patent

Three-dimensional photoacoustic imager and methods for calibrating an imager

Life of this patent

Abstract

Claims26