Statistics of maximum photon penetration depth in a two-layer diffusive medium

Martelli, Fabrizio; Pifferi, Antonio; Farina, Andrea; Amendola, Caterina; Maffeis, Giulia; Tommasi, Federico; Cavalieri, Stefano; Spinelli, Lorenzo; Torricelli, Alessandro

doi:10.1364/boe.507294

Cited by 2 publications

(1 citation statement)

References 34 publications

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“…The larger absolute difference is <1 cm -1 resulting in a relative difference <20% in the worst case of µs' = 5 cm -1 . Anyway, small changes in the scattering coefficient have limited influence on the characteristics of light propagation in diffusive media, but they might affect the estimate of parameters derived by CW NIRS if not properly considered 42 .…”

Section: Discussionmentioning

confidence: 99%

Robustness of time domain near infrared spectroscopy to variations in skin pigmentation

Lacerenza,

Amendola,

Bargigia

et al. 2024

Preprint

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Recently, skin pigmentation has been shown to affect the performance of pulse oximeters and other light-based techniques like photoacoustic imaging, tissue oximetry, and continuous wave near infrared spectroscopy. Evaluating the robustness to changes in skin pigmentation is therefore essential for the proper use of optical technologies in the clinical scenario. We conducted systematic time domain near infrared spectroscopy measurements on calibrated tissue phantoms and in vivo on volunteers during static and dynamic (i.e., arterial occlusion) measurements. To simulate varying melanosome volume fractions in the skin, we inserted, between the target sample and the measurement probe, thin tissue phantoms made of silicone and nigrosine (skin phantoms). Additionally, we conducted an extensive measurement campaign on a large cohort of pediatric subjects, covering the full spectrum of skin pigmentation. Our findings consistently demonstrate that skin pigmentation has a negligible effect on time domain near infrared spectroscopy results, underscoring the reliability and potential of this emerging technology in diverse clinical settings.

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Section: Discussionmentioning

confidence: 99%

Robustness of time domain near infrared spectroscopy to variations in skin pigmentation

Lacerenza,

Amendola,

Bargigia

et al. 2024

Preprint

Self Cite

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Cerebral baseline optical and hemodynamic properties in pediatric population: a large cohort time-domain near-infrared spectroscopy study

Calcaterra,

Lacerenza,

Amendola

et al. 2024

Neurophoton.

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Reference cerebral near-infrared spectroscopy (NIRS) data on the pediatric population are scarce, and in most cases, only cerebral oxygen saturation (SO 2 ) measured by continuous wave spatially resolved spectroscopy NIRS is reported. Absolute data for baseline optical and hemodynamic parameters are missing.Aim: We aimed at collecting baseline cerebral optical parameters [absorption coefficient, μ a ; reduced scattering coefficient, μ 0 s ; differential pathlength factor (DPF)] and hemodynamic parameters [oxy-hemoglobin content (HbO 2 ), deoxyhemoglobin content (HHb), total hemoglobin content (tHB), SO 2 ] in a large cohort of pediatric patients. The objectives are to establish reference optical values in this population and evaluate the reproducibility of a commercial time domain (TD) NIRS tissue oximeter.Approach: TD NIRS measurements were performed in the prefrontal cortex at 686 and 830 nm with a 2.5-cm source-detector distance and 1-Hz acquisition rate. Five independent measurements (after probe replacement) were taken for every subject. TD NIRS data were fitted to a photon diffusion model to estimate the optical parameters. From the absorption coefficients, the hemodynamic parameters were derived by Beer's law. Auxological and physiological information was also collected to explore the potential correlations with NIRS data. Results:We measured 305 patients in the age range of 2 to 18 years. Absolute values for baseline optical and hemodynamic parameters were shown as a function of age and auxological variables. From the analysis of the repositioning after probe replacement, the time-domain near-infrared spectroscopy device exhibited an average precision (intended as coefficient of variation) of <5% for μ 0 s , DPF, HbO 2 , HHb, and tHb, whereas precision was <2% for SO 2 . Conclusions:We provided baseline values for optical and hemodynamic parameters in a large cohort of healthy pediatric subjects with good precision, providing a foundation for future investigations into clinically relevant deviations in these parameters.

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Statistics of maximum photon penetration depth in a two-layer diffusive medium

Cited by 2 publications

References 34 publications

Robustness of time domain near infrared spectroscopy to variations in skin pigmentation

Robustness of time domain near infrared spectroscopy to variations in skin pigmentation

Cerebral baseline optical and hemodynamic properties in pediatric population: a large cohort time-domain near-infrared spectroscopy study

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