The use of tissue phantoms as calibrators to transfer SI-referenced scale to an imager offers convenience, compared to
other methods of calibration. The tissue phantoms are calibrated separately for radiance at emission wavelength per
irradiance at excitation wavelength. This calibration is only performed at a single geometric configuration, typically
with the detector normal to the sample. In the clinic however, the imager can be moved around, resulting in a geometric
configuration different from the calibration configuration. In this study, radiometric measurements are made at different
sample-imager angles to test whether the tissue phantoms are Lambertian and the angular limits to which the calibration
values hold true.
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