Abstract Although Blood Oxygenation Level Dependent (BOLD) functional MRI (fMRI) is widely used to examine brain activation in adults, technical and logistical challenges frequently limit the ability to perform fMRI scans readily and longitudinally in infants, particularly in those at greatest risk for adverse neurodevelopmental outcomes and developmental delays. As a consequence, prognostics are made on general basis and cannot be individualized for optimal management. Functional Near-Infrared Spectroscopy – Diffuse Optical Tomography (fNIRS-DOT) imaging promises to be an alternative imaging technique. The current fNIRS-DOT imaging are limited to cortex regions and unable to interrogate deep structures such as the basal ganglia and thalamus that are often involved premature infant brain injury. Recently, we reported a continuous wave-based transcranial near infrared optical imaging system, called Cap-based Transcranial Optical Tomography (CTOT) that employed a single, GaAs intensified, CCD detector array to image whole brain hemodynamic activity in an awake child with seconds of acquisition time. However, the substantial readout time of the CCD detector and slow mechanical switching of source and detector fiber optics resulted in large dead-times that lengthened measurement times. Armed with our preliminary data of the clinical feasibility, we propose to speed up measurement times by adapting recent advances of fast read-out, scientific CMOS detector arrays along with microelectromechanical systems (MEMS) for novel dynamic range control, automated calibration, and optical switching of source and collection fiber optics in order to enable sub-second, dynamic CTOT mapping. The significance and innovation of this approach will be substantial, as never before has a nonintrusive, noninvasive methodology been developed to completely elucidate whole brain hemodynamic activity in infants. Our specific aims are to: (1) refine our CTOT imaging system with a single, GaAs intensified integrating detector, a MEMS optical switch for source fiber optics and a digital micromirror device for detector fiber optics to enable rapid, dynamic imaging; and (2) validate CTOTfNIRS derived hemodynamic activity in infants undergoing BOLD fMRI. If successful, the proposed work will provide the first, rapid whole brain CTOT imaging system for sensitive assessment of brain hemodynamic activity in infants. In the short term, CTOT images will eventually help parents, physicians and therapists best plan and care for children with brain deficits so that their quality of life is optimized as they progress through childhood.