Multiple-slice imaging of a tissue-equivalent phantom by use of time-resolved optical tomography

Following several years of development the construction of a multichannel t ime-resolved imaging device for medical optical tomography has been complet ed. Images are reconstructed from time-resolved measurements by use of a sc heme that employs a finite-element diffusion-based forward model and an ite rative reconstruction solver. Prior to testing on clinical subjects the ful ly automated instrument and the reconstruction software are evaluated with tissue-equivalent phantoms. We describe our first attempt to generate multi ple-slice images of a phantom without uniform properties along the axial di rection, while still using a computationally fast two-dimensional reconstru ction algorithm. The image quality is improved by the employment of an appr oximate correction method that uses scaling factors derived from the ratios of finite-element forward simulations in two and three spatial dimensions. The 32-channel system was employed to generate maps of the internal scatte ring and the absorption properties at 14 different transverse planes across the phantom. The images clearly reveal the locations of small inhomogeneou s regions embedded within the phantom. These results were obtained by use o f purely temporal data and without resource to reference measurements. (C) 2000 Optical Society of America OCIS codes: 170.3010, 170.6920, 170.6960, 1 70.0110.