Apoptosis induces temporal increase in attenuation as measured by optical coherence tomography

Optical coherence tomography (OCT) was used to determine optical properties of pelleted human fibroblasts in which necrosis or apoptosis was induced. We analyzed the OCT data including both the scattering properties of the medium and the axial point spread function of the OCT system. We measured that the optical attenuation coefficient in necrotic cells decreased from 2.2 ±0.3 mm^-1 to 1.3 ±0.6 mm^-1, whereas with the apoptotic cells a clear increase (up to 6.4 ±1.7 mm^-1) in scattering was observed. The results on cultured cells a presented in this study indicate the ability of OCT to detect and differentiate between viable, apoptotic and necrotic cells based on their backscatter properties. This functional supplement to high-resolution OCT imaging can be of great clinical benefit, enabling on line monitoring of tissues, e.g. for feedback in cancer treatment.