Two-Dimensional Photoacoustic Imaging by Use of Fourier-Transform Image Reconstruction and a Detector with an Anisotropic Response
Abstract
Theoretical and experimental aspects of two-dimensional (2D) biomedical photoacoustic imaging have been investigated. A 2D Fourier-transform-based reconstruction algorithm that is significantly faster and produces fewer artifacts than simple radial backprojection methods is described. The image-reconstruction time for a 208 x 482 pixel image is ~1 s. For the practical implementation of 2D photoacoustic imaging, a rectangular detector geometry was used to obtain an anisotropic detection sensitivity in order to reject out-of-plane signals, thereby permitting a tomographic image slice to be reconstructed. This approach was investigated by the numerical modeling of the broadband directional response of a rectangular detector and imaging of various spatially calibrated absorbing targets immersed in a turbid phantom. The experimental setup was based on a Q -switched Nd:YAG excitation laser source and a mechanically line-scanned Fabry-Perot polymer-film ultrasound sensor. For a 800 μm x 200 μm rectangular detector, the reconstructed image slice thickness was 0.8 mm up to a vertical distance of z = 3.5 mm from the detector, increasing thereafter to 2 mm at z = 10 mm. Horizontal and vertical spatial resolutions within the reconstructed slice were approximately 200 and 60 μm, respectively.
- Publication:
-
Applied Optics
- Pub Date:
- April 2003
- DOI:
- 10.1364/AO.42.001899
- Bibcode:
- 2003ApOpt..42.1899K
- Keywords:
-
- biomedical imaging;
- photoacoustic spectroscopy;
- image reconstruction;
- Fourier transform optics;
- calibration;
- turbidity;
- infrared spectra;
- image resolution