title: Digital-signal-processor-based dynamic imaging system for optical tomography.
abstract: In this article, we introduce a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this continuous wave instrument is a digital signal processor (DSP) that collects, collates, processes, and filters the digitized data set. The processor is also responsible for managing system timing and the imaging routines which can acquire real-time data at rates as high as 150 Hz. Many of the synchronously timed processes are controlled by a complex programmable logic device that is also used in conjunction with the DSP to orchestrate data flow. The operation of the system is implemented through a comprehensive graphical user interface designed with LABVIEW software which integrates automated calibration, data acquisition, data organization, and signal postprocessing. Performance analysis demonstrates very low system noise (approximately 1 pW rms noise equivalent power), excellent signal precision (<0.04%-0.2%) and long term system stability (<1% over 40 min). A large dynamic range (approximately 190 dB) accommodates a wide scope of measurement geometries and tissue types. First experiments on tissue phantoms show that dynamic behavior is accurately captured and spatial location can be correctly tracked using this system.
authors.affiliation: Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace MC8904, New York, NY 10027, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Lasker
authors.forename: James M
authors.initials: JM
authors.lastname: Masciotti
authors.forename: Matthew
authors.initials: M
authors.lastname: Schoenecker
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Schmitz
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Hielscher
mesh_terms: D000465:Algorithms; D003199:Computer Systems; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D041622:Tomography, Optical / Q000295:instrumentation*