Title

Characterization and standardization of tissue-simulating protoporphyrin IX optical phantoms

Document Type

Article

Publication Date

3-1-2016

Publication Title

Journal of Biomedical Optics

Abstract

Optical devices for measuring protoporphryin IX (PpIX) fluorescence in tissue are routinely validated by measurements in optical phantoms. Yet there exists limited data to form a consensus on the recipe for phantoms that both mimic the optical properties found in tissue and yield a reliable and stable relationship between PpIX concentration and the fluorescence remission intensity. This study characterizes the influence of multiple phantom components on PpIX fluorescence emission intensity, using Intralipid as the scattering source, bovine whole blood as the background absorber, and Tween as a surfactant to prevent PpIX aggregation. Optical measurements showed a linear proportionality (r>0.99" role="presentation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 15px; line-height: normal; font-family: "Museo Sans-300", Arial, "Sans Serif"; vertical-align: baseline; display: inline; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">r>0.99r>0.99) between fluorescence intensity and PpIX concentration (0.1 to 10  μg/mL" role="presentation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 15px; line-height: normal; font-family: "Museo Sans-300", Arial, "Sans Serif"; vertical-align: baseline; display: inline; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">10μg/mL10  μg/mL) over a range of Intralipid (1 to 2%) and whole blood (0.5 to 3%) for phantoms containing low surfactant (≤0.1%" role="presentation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 15px; line-height: normal; font-family: "Museo Sans-300", Arial, "Sans Serif"; vertical-align: baseline; display: inline; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">≤0.1%≤0.1%), with fluorescence intensities and scattering and absorption properties stable for 5 h after mixing. The role of surfactant in PpIX phantoms was found to be complex, as aggregation was evident in aqueous nonturbid phantoms with no surfactant (0% Tween), and avoided in phantoms containing Intralipid as the scattering source with no additional or low amounts of added surfactant (≤0.1%" role="presentation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 15px; line-height: normal; font-family: "Museo Sans-300", Arial, "Sans Serif"; vertical-align: baseline; display: inline; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">≤0.1%≤0.1%Tween). Conversely, phantoms containing higher surfactant content (>0.1%" role="presentation" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-stretch: inherit; font-size: 15px; line-height: normal; font-family: "Museo Sans-300", Arial, "Sans Serif"; vertical-align: baseline; display: inline; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">>0.1%>0.1% Tween) and whole blood showed interactions that distorted the fluorescence emissions.

DOI

10.1117/1.JBO.21.3.035003

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