Functional near-infrared spectroscopy (fNIRS) is a non-invasive method of imaging brain function, and it is portable and much cheaper than other functional imaging modalities, such as functional MRI. It is beneficial for users to validate their fNIRS systems on a controlled phantom, but for such a phantom to be worthwhile, it must have well-characterized optical properties and be able to simulate the hemodynamic response (HDR). In this paper, we describe a dynamic phantom capable of producing reproducible fNIRS data, and we describe methods for characterizing the optical properties of this phantom. This phantom has already produced fNIRS data with spatially accurate simulated HDR signals. Additionally, we propose modifications for this phantom to produce accurate X-ray and computed tomography (CT) data to make it viable for multimodal imaging systems. CT brain imaging allows high-resolution structural imaging, but with contrast agents some functional information can also be mapped. The combination of CT and fNIRS may be desirable for easily and more accurately estimating differential pathlength factor (DPF) values across a patient’s head, and it may be beneficial for diagnosing and treating patients suffering from head trauma and other neurological conditions.
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