Qth10

Reflectance and transmittance measurements were collected from 1 mm slices of solidified gelatin mixtures, HAP and gelatin powder with an integrating sphere (IS) (IS200; Thorlabs; New Jersey; USA) illuminated using a quartz-tungsten-halogen (QTH) lamp (QTH10; Thorlabs; New Jersey; USA). Bulk optical properties ( ${\mu }_a,{\mu }_s^{\prime }$ ) were calculated from reflectance and transmission measurements using the inverse adding-doubling (IAD) technique^{[31 ]}, which performs an iterative solution to the radiative transport equation. For the purpose of IAD, anisotropy was held constant at 0.75, and the refractive index was also set statically to 1.51 for the gelatin matrix medium, and 1.651 for the HAP capsule. Optical property spectra were nearly monotonic in the Raman fingerprint window for the 785 nm excitation wavelength evaluated here, and on a similar order to those reported in literature for soft tissues and bone^{[32 (link)]} (835 to 915 nm for $\lambda$ , 780-1800 cm⁻¹ Raman Shifts). Mean optical property values were; Gelatin matrix ${\mu }_a=0.7c{m}^{-1}{\mu }_s^{\prime }=1.6\times {10}^{-7}c{m}^{-1}$ , HAP ${\mu }_a=11c{m}^{-1}{\mu }_s^{\prime }=770c{m}^{-1}$ , however the full spectra were input in the MC model.