Ephrat Pinhas, Keenliside Lynn, Seabrook Adam, Prato Frank S, Carson Jeffrey J L
Lawson Health Research Institute, Imaging Program, London, Ontario N6A 4V2, Canada.
J Biomed Opt. 2008 Sep-Oct;13(5):054052. doi: 10.1117/1.2992131.
Photoacoustic imaging (PAI) has the potential to acquire 3-D optical images at high speed. Attempts at 3-D photoacoustic imaging have used a dense 2-D array of ultrasound detectors or have densely scanned a single detector on a 2-D surface. The former approach is costly and complicated to realize, while the latter is inherently slow. We present a different approach based on a sparse 2-D array of detector elements and an iterative reconstruction algorithm. This approach has the potential for fast image acquisition, since no mechanical scanning is required, and for simple and compact construction due to the smaller number of detector elements. We obtained spatial sensitivity maps of the sparse array and used them to optimize the image reconstruction algorithm. We then validated the method on phantoms containing 3-D distributions of optically absorbing point sources. Reconstruction of the point sources from the time-domain signals resulted in images with good contrast and accurate localization (< or =1 mm error). Image acquisition time was 1 s. The results suggest that 3-D PAI with a sparse array of detector elements is a viable approach. Furthermore, the rapid acquisition speed indicates the possibility of high frame rate 3-D PAI.
光声成像（PAI）有潜力高速获取三维光学图像。三维光声成像的尝试采用了密集的二维超声探测器阵列，或者在二维表面上对单个探测器进行密集扫描。前一种方法实现起来成本高且复杂，而后一种方法本质上速度慢。我们提出了一种基于稀疏二维探测器元件阵列和迭代重建算法的不同方法。这种方法有快速图像采集的潜力，因为不需要机械扫描，并且由于探测器元件数量较少，结构简单紧凑。我们获得了稀疏阵列的空间灵敏度图，并将其用于优化图像重建算法。然后，我们在包含光吸收点源三维分布的体模上验证了该方法。从时域信号重建点源得到了具有良好对比度和精确定位（误差≤1毫米）的图像。图像采集时间为1秒。结果表明，使用稀疏探测器元件阵列的三维PAI是一种可行的方法。此外，快速的采集速度表明了高帧率三维PAI的可能性。
