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Fluorescence and diffuse reflectance provide similar accuracy in recovering fluorophore concentration at short source-detector separations.

ABSTRACT: Quantitative fluorescence spectroscopy requires corresponding reflectance measurements to correct for tissue absorption and scattering. However, it is unclear whether fluorescence adds value beyond the diffuse reflectance measurements necessary for correction. The goal of this study was to compare the accuracy of fluorescence and diffuse reflectance spectroscopy in recovering the concentration of a high-extinction fluorophore, methylene blue (MB), using a compact fiber-optic probe. Fluorescence and diffuse reflectance measurements of tissue simulating phantoms were made using a fiber-optic probe with source-detector separations of 288-1300 μm. Average error in recovered fluorophore concentration was 20.4% for fluorescence and 15.0% for reflectance, though this difference was not significant (p=0.77). Both methods returned concentrations that were similar to known MB concentrations (p≥0.79 in both cases). Fluorescence quantification of the concentration of a high extinction fluorophore did not significantly improve accuracy relative to diffuse reflectance. Investigators should consider whether fluorescence measurements are necessary for a given application.

SUBMITTER: Roccabruna JR

PROVIDER: S-EPMC9401209 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Fluorescence and diffuse reflectance provide similar accuracy in recovering fluorophore concentration at short source-detector separations.

Roccabruna Jacob R JR Bridger Karina G KG Baran Timothy M TM

Journal of modern optics 20220511 12

Quantitative fluorescence spectroscopy requires corresponding reflectance measurements to correct for tissue absorption and scattering. However, it is unclear whether fluorescence adds value beyond the diffuse reflectance measurements necessary for correction. The goal of this study was to compare the accuracy of fluorescence and diffuse reflectance spectroscopy in recovering the concentration of a high-extinction fluorophore, methylene blue (MB), using a compact fiber-optic probe. Fluorescence ...[more]

PMID: 36035874

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Project description:Accurately detecting nitrogen (N) deficiency and determining the need for additional N fertilizer is a key challenge to achieving precise N management in many crops, including rice (Oryza sativa L.). Many remotely sensed vegetation indices (VIs) have shown promise in this regard; however, it is not well-known if VIs measured from different sensors can be used interchangeably. The objective of this study was to quantitatively test and compare the ability of VIs measured from an aerial and proximal sensor to predict the crop yield response to top-dress N fertilizer in rice. Nitrogen fertilizer response trials were established across two years (six site-years) throughout the Sacramento Valley rice-growing region of California. At panicle initiation (PI), unmanned aircraft system (UAS) Normalized Difference Red-Edge Index (NDREUAS) and GreenSeeker (GS) Normalized Difference Vegetation Index (NDVIGS) were measured and expressed as a sufficiency index (SI) (VI of N treatment divided by VI of adjacent N-enriched area). Following reflectance measurements, each plot was split into subplots with and without top-dress N fertilizer. All metrics evaluated in this study indicated that both NDREUAS and NDVIGS performed similarly with respect to predicting the rice yield response to top-dress N at PI. Utilizing SI measurements prior to top-dress N fertilizer application resulted in a 113% and 69% increase (for NDREUAS and NDVIGS, respectively) in the precision of the rice yield response differentiation compared to the effect of applying top-dress N without SI information considered. When the SI measured via NDREUAS and NDVIGS at PI was ≤0.97 and 0.96, top-dress N applications resulted in a significant (p < 0.05) increase in crop yield of 0.19 and 0.21 Mg ha-1, respectively. These results indicate that both aerial NDREUAS and proximal NDVIGS have the potential to accurately predict the rice yield response to PI top-dress N fertilizer in this system and could serve as the basis for developing a decision support tool for farmers that could potentially inform better N management and improve N use efficiency.

Project description:BackgroundDiffusely reflected light is influenced by cytologic and morphologic changes that take place during tissue transformation, such as, nuclear changes, extracellular matrix structure and composition as well as blood flow. Albeit with varying degree of sensitivity and specificity, the properties of diffusely reflected light in discriminating a variety of oral lesions have been demonstrated by our group in multiple studies using point monitoring systems. However, the point monitoring system could not identify the region with the most malignant potential in a single sitting.MethodsIn order to scan the entire lesion, we developed a multi-spectral imaging camera system that records diffuse reflectance (DR) images of the oral lesion at 545 and 575 nm with white light illumination. The diagnostic accuracy of the system for 2-dimensional DR imaging of pre-malignant and malignant changes in the oral cavity was evaluated through a clinical study in 55 patients and 23 healthy volunteers. The DR imaging data were compared with gold standard tissue biopsy and histopathology results.ResultsIn total 106- normal/clinically healthy sites, 20- pre-malignant and 29- malignant (SCC) sites were compared. While the median pixel value of the R545/R575 image ratio for normal/clinically healthy tissue was 0.87 (IQR?=?0.82-0.94), they were 1.35 (IQR?=?1.13-1.67) and 2.44 (IQR?=?1.78-3.80) for pre-malignant and malignant lesions, respectively. Area under the ROC curve to differentiate malignant from normal/clinically healthy [AUC?=?0.99 (95% CI: 0.99-1.00)], pre-malignant from normal/clinically healthy [AUC?=?0.94 (95% CI: 0.86-1.00)], malignant from pre-malignant [AUC?=?0.84 (95% CI: 0.73-0.95)] and pre-malignant and malignant from normal/clinically healthy [AUC?=?0.97 (95% CI: 0.94-1.00)] lesions were desirable.ConclusionWe find DR imaging to be very effective as a screening tool in locating the potentially malignant areas of oral lesions with relatively good diagnostic accuracy while comparing it to the gold standard histopathology.

Dataset Information

Fluorescence and diffuse reflectance provide similar accuracy in recovering fluorophore concentration at short source-detector separations.

Publications

Fluorescence and diffuse reflectance provide similar accuracy in recovering fluorophore concentration at short source-detector separations.

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