Module 3.1: Data Fitting Wendy Tanamai & Albert Cerussi Beckman Laser Institute University of California, Irvine

NTROI DOS Workshop, 2007 Module 3.1 Outline How data is fit Data file summary Using the GUI

NTROI DOS Workshop, 2007 Module 3.1 How Data is Fit FDPM Data –Data inputs phase and amplitude vs. modulation frequency sample (tissue) and reference (phantom) –Calibration for: FDPM amplitude (ratio) FDPM phase (difference)

NTROI DOS Workshop, 2007 Module 3.1 Raw FDPM

NTROI DOS Workshop, 2007 Module 3.1 How Data is Fit FDPM Data (continued) –Conversion to Real & Imaginary –lsqcurvefit function in MATLAB using both real and imaginary together –Some weighted fitting options –Done for each laser diode

NTROI DOS Workshop, 2007 Module 3.1 Processed FDPM

NTROI DOS Workshop, 2007 Module 3.1 How Data is Fit Broadband Data –Dark count subtraction (usually done in acquisition) –Spectral calibration

NTROI DOS Workshop, 2007 Module 3.1 Spectral Calibration

NTROI DOS Workshop, 2007 Module 3.1 Spectral Calibration

NTROI DOS Workshop, 2007 Module 3.1 How Data is Fit Broadband Data –Power Law fit to FDPM scattering –Scattering removed from broadband reflectance –FDPM absorption used to scale broadband reflectance –Solve for absorption using MATLAB ‘fzero’

NTROI DOS Workshop, 2007 Module 3.1 How Data is Fit Physiological Fitting –Assume 4-chromophores –Non-zero least squares –Usually fit with baseline

NTROI DOS Workshop, 2007 Module 3.1 Processed Spectra

NTROI DOS Workshop, 2007 Module 3.1 Data Files (Acquired) All files are ASCII FDPM data has ‘dcswitch’ tag –for all modulation frequencies –one for each location SPEC data has ‘tis’ tag –for all wavelengths –one for each location Cal files named phantom/standard

NTROI DOS Workshop, 2007 Module 3.1 Data Files (Processed) _dBSUM file has all processed results for both FDPM (only) and FDPM-Broadband for all spatial locations _MUA file has broadband absorption spectra and chromophore fits for all spatial locations _MUS file has broadband reduced scattering spectra for all spatial locations

NTROI DOS Workshop, 2007 Module 3.1 Data Files (Processed) _dBMU file has all FDPM values for each wavelength and all spatial locations _specR has the calibrated/scaled broadband reflectance spectra for all spatial locations _gbfi (coming soon) quality of fit data for all fits and all spatial locations

NTROI DOS Workshop, 2007 Module 3.1 Data Files (Processed) Other processing options –Gridimager program (Visualization) –Double differential analysis (can download) –Bound Water/Temperature analysis

NTROI DOS Workshop, 2007 Module 3.1 Using the GUI Demo of the GUI