Correcting Cherenkov images for large-scale tissue-optical property attenuation using SFDI and patterned light reflectance for quantitative dosimetry

Tissue optical properties attenuate a substantial percentage of the optical light being detected during real-time Cherenkov acquisition, which distortsthe signal linearity previously observed with absorbed dose in homogeneous media. This hinders progression toward establishing quantitative dosimetry using Cherenkov imaging in vivo. By spectrally weighting effective attenuation (μeff) maps generated by multi-wavelength Spatial Frequency Domain Imaging (SFDI), it became possible to more successfully correct clinical Cherenkov images for areolar attenuation (6% difference, as compared to the treatment plan) compared to selecting one wavelength channel in a previous study (41% difference). Additionally, using a reflected light-based patient positioning system, we were able to characterize and correct for gross tissue optical properties in patient images, namely for large-scale surface and subsurface attenuation. While the use of wide-field SFDI enabled pixel-bypixel corrections, the benefit of using an integrated, light-based system for reflectance-based corrections negates the use of an external imaging system, which substantially smooths workflow.