Digital lock-in detection system based on single photon counting for near-infrared functional brain imaging

Wei Meng; Hui Guo; Ming Liu; Xi Yi; Linhui Wu; Huijuan Zhao; Feng Gao

doi:10.1117/12.2000623

25 March 2013 Digital lock-in detection system based on single photon counting for near-infrared functional brain imaging

Wei Meng, Hui Guo, Ming Liu, Xi Yi, Linhui Wu, Huijuan Zhao, Feng Gao

Author Affiliations +

Proceedings Volume 8578, Optical Tomography and Spectroscopy of Tissue X; 85782Q (2013) https://doi.org/10.1117/12.2000623
Event: SPIE BiOS, 2013, San Francisco, California, United States

Abstract

Near infrared (NIR) diffuse optical imaging (DOI) are increasingly used to detect hemodynamic changes in the cerebral cortex induced by brain activity. For the sake of capturing the dynamic changes in real-time imaging applications, such as brain imaging, digital lock-in detection technique could be applied. Using particular modulation and sampling constraints and averaging filters, one can achieve optimal noise reduction and discrimination between sources in different modulation frequencies. In this paper, we designed and developed a compact dual-wavelength continuous wave DOI system based on the single photon counting digital lock-in detection technique. According to the frequency division multiplexing light source coding technique, sine waves with different frequencies are generated so as to amplitude-modulate two laser sources with different wavelengths. The diffuse light is detected by photomultiplier tubes (PMTs) and the data is collected by the detection channels simultaneously. A digital lock-in detection circuit for photon counting measurement module and a DDS (Direct Digital Synthesizer) signal generation module were separately implemented in two FPGA development platforms. To validate the feasibility and functionality of the developed system, a series of experimental tests were performed. Preliminary results show that the system could be used to reconstruct the absorption coefficient and could separate the response of the dual wavelength sources which were modulated by sine signals of different frequencies effectively. In addition, several imaging experiments were performed on the semi-infinite solid phantom to find the “best imaging position” for a given source-detector placement.

Citation Download Citation

Wei Meng, Hui Guo, Ming Liu, Xi Yi, Linhui Wu, Huijuan Zhao, and Feng Gao "Digital lock-in detection system based on single photon counting for near-infrared functional brain imaging", Proc. SPIE 8578, Optical Tomography and Spectroscopy of Tissue X, 85782Q (25 March 2013); https://doi.org/10.1117/12.2000623

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available