TY - JOUR
T1 - Fundamental effects of array density and modulation frequency on image quality of diffuse optical tomography
AU - Fan, Weihao
AU - Trobaugh, Jason W.
AU - Zhang, Chengfeng
AU - Yang, Dalin
AU - Culver, Joseph P.
AU - Eggebrecht, Adam T.
N1 - Publisher Copyright:
© 2024 The Author(s). Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.
PY - 2025/2
Y1 - 2025/2
N2 - Background: Diffuse optical tomography (DOT) provides three-dimensional image reconstruction of chromophore perturbations within a turbid volume. Two leading strategies to optimize DOT image quality include, (i) arrays of regular, interlacing, high-density (HD) grids of sources and detectors with closest spacing less than 15 mm, or (ii) source modulated light of order ∼100 MHz. Purpose: However, the general principles for how these crucial design parameters of array density and modulation frequency may interact to provide an optimal system design have yet to be elucidated. Methods: Herein, we systematically evaluated how these design parameters effect image quality via multiple key metrics. Specifically, we simulated 32 system designs with realistic measurement noise and quantified localization error, spatial resolution, signal-to-noise, and localization depth of field for each of ∼85 000 point spread functions in each model. Results: We found that array density had a far stronger effect on image quality metrics than modulation frequency. Additionally, model fits for image quality metrics revealed that potential improvements diminish with regular arrays denser than 9 mm closest spacing. Further, for a given array density, 300 MHz source modulation provided the deepest reliable imaging compared to other frequencies. Conclusions: Our results indicate that both array density and modulation frequency affect the spatial sampling of tissue, which asymptotically saturates due to photon diffusivity within a turbid volume. In summary, our results provide comprehensive perspectives for optimizing future DOT system designs in applications from wearable functional brain imaging to breast tumor detection.
AB - Background: Diffuse optical tomography (DOT) provides three-dimensional image reconstruction of chromophore perturbations within a turbid volume. Two leading strategies to optimize DOT image quality include, (i) arrays of regular, interlacing, high-density (HD) grids of sources and detectors with closest spacing less than 15 mm, or (ii) source modulated light of order ∼100 MHz. Purpose: However, the general principles for how these crucial design parameters of array density and modulation frequency may interact to provide an optimal system design have yet to be elucidated. Methods: Herein, we systematically evaluated how these design parameters effect image quality via multiple key metrics. Specifically, we simulated 32 system designs with realistic measurement noise and quantified localization error, spatial resolution, signal-to-noise, and localization depth of field for each of ∼85 000 point spread functions in each model. Results: We found that array density had a far stronger effect on image quality metrics than modulation frequency. Additionally, model fits for image quality metrics revealed that potential improvements diminish with regular arrays denser than 9 mm closest spacing. Further, for a given array density, 300 MHz source modulation provided the deepest reliable imaging compared to other frequencies. Conclusions: Our results indicate that both array density and modulation frequency affect the spatial sampling of tissue, which asymptotically saturates due to photon diffusivity within a turbid volume. In summary, our results provide comprehensive perspectives for optimizing future DOT system designs in applications from wearable functional brain imaging to breast tumor detection.
KW - array density
KW - diffuse optical tomography
KW - frequency domain
KW - functional near-infrared spectroscopy
KW - image quality
KW - inverse problem
KW - localization depth of field
KW - modulation frequency
KW - point spread function
KW - regularization parameters
KW - spatial resolution
UR - http://www.scopus.com/inward/record.url?scp=85208024034&partnerID=8YFLogxK
U2 - 10.1002/mp.17491
DO - 10.1002/mp.17491
M3 - Article
C2 - 39494917
AN - SCOPUS:85208024034
SN - 0094-2405
VL - 52
SP - 1045
EP - 1057
JO - Medical physics
JF - Medical physics
IS - 2
ER -