Multi-modulated frequency domain high density diffuse optical tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging Technology
• Photonics

Background:

• Frequency domain (FD) high density diffuse optical tomography (HD-DOT) offers theoretical advantages over continuous wave (CW) measurements.
• Utilizing varying or combined modulation frequencies (mFD) is proposed to further enhance imaging accuracy.

Purpose of the Study:

• To quantitatively evaluate the performance of mFD HD-DOT compared to conventional FD and CW methods.
• To assess the impact of mFD on imaging accuracy using a solid inhomogeneous phantom.

Main Methods:

• HD-DOT measurements were performed on the NEUROPT phantom using intensity and phase data.
• Three modulation frequencies (78 MHz, 141 MHz, and 203 MHz) were employed in mFD, FD, and CW configurations.
• Imaging accuracy was evaluated using metrics such as localization error (LOCA), full width half maximum (FWHM), and effective resolution (ERES).

Main Results:

• mFD demonstrated superior performance in both absolute (iterative) and temporal (linear) tomographic imaging compared to FD and CW.
• Across all phantom rods, mFD achieved a 61.3% better LOCA than FD and 106.1% better than CW.
• While CW showed a slight advantage in FWHM (6.0% better than FD and mFD), mFD provided superior ERES (1.20% better than FD, 9.83% better than CW).

Conclusions:

• mFD HD-DOT significantly improves imaging accuracy, outperforming conventional FD and CW methods.
• This approach effectively minimizes noise in FD phase data while leveraging its strengths for enhanced contrast.
• mFD represents a promising advancement for high-resolution diffuse optical tomography.