Double-integrating-sphere system at the National Institute of Standards and Technology in support of measurement standards for the determination of optical properties of tissue-mimicking phantoms.
There is a need for a common reference point that will allow for the comparison of the optical properties of tissue-mimicking phantoms. After a brief review of the methods that have been used to measure the phantoms for a contextual backdrop to our approach, this paper reports on the establishment of a standardized double-integrating-sphere platform to measure absorption and reduced scattering coefficients of tissue-mimicking biomedical phantoms. The platform implements a user-friendly graphical user interface in which variations of experimental configurations and model-based analysis are implemented to compute the coefficients based on a modified inverse adding-doubling algorithm allowing a complete uncertainty evaluation. Repeatability and validation of the measurement results of solid phantoms are demonstrated for three samples of different thicknesses, d = 5.08 mm, 7.09 mm, and 9.92 mm, with an absolute error estimate of 4.0% to 5.0% for the absorption coefficient and 11% to 12% for the reduced scattering coefficient (k = 2). The results are in accordance with those provided by the manufacturer. Measurements with different polarization angles of the incident light are also presented, and the resulting optical properties were determined to be equivalent within the estimated uncertainties.
National Institute of Standards and Technology, Physical Measurement Laboratory, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States.
Paul
P
Lemaillet
Institut National d'Optique, 2740 Einstein Street, Québec G1P 4S4, Canada.
Jean-Pierre
JP
Bouchard
National Institute of Standards and Technology, Physical Measurement Laboratory, 325 Broadway Street, Boulder, Colorado 80305, United States.
Jeeseong
J
Hwang
National Institute of Standards and Technology, Physical Measurement Laboratory, 100 Bureau Drive, Gaithersburg, Maryland 20899, United States.
David W
DW
Allen
D000465:Algorithms; D016880:Anisotropy; D002138:Calibration; D003952:Diagnostic Imaging / Q000592:standards*; D006801:Humans; D007834:Lasers; D055095:Optics and Photonics / Q000592:standards*; D019047:Phantoms, Imaging / Q000592:standards*; D012031:Refractometry; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014481:United States