Piezoelectric line detector array for photoacoustic tomography

• Main Authors: Guenther Paltauf, Petra Hartmair, Georgi Kovachev, Robert Nuster
• Format: Article
• Language: English
• Published: Elsevier 2017-12-01
• Series: Photoacoustics
• Subjects: Optoacoustic; Thermoacoustic; Tomography; Piezoelectric polymer; Ultrasound array
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213597917300307

Photoacoustic tomography relies on a dense coverage of the surface surrounding the imaged object with ultrasound sensors in order to enable an accurate reconstruction. A curved arrangement of integrating line sensors is proposed that is able to acquire data for a linear projection image of the absorbed energy density distribution in the object. Upon rotation of the object relative to the array, three-dimensional (3D) images can be obtained. The proposed design is based on the cost-effective piezoelectric polymer film technology with 64 line shaped sensors arranged on a half-cylindrical surface. It is combined with an optical parametric oscillator for the near infrared as a source for laser pulses. Image reconstruction from recorded signals consists of two-dimensional (2D) back projection followed by an inverse Radon transform. The tomograph exhibits a spatial resolution on the order of 200 to 250 μm. In a phantom experiment, the steps from acquisition of a single, 2D projection image to a full 3D image are demonstrated. Finally, in vivo projection images of a human finger are shown, revealing the near real-time imaging capability of the device in 2D.