Swept source optical coherence tomography for radiation-enhanced hepatocellular carcinoma cell invasion imaging

In this study, we evaluated the effectiveness of using swept-source optical coherence tomography (SS-OCT) to monitor the enhancement of hepatocellular carcinoma (HCC) cell invasiveness by radiation. SS-OCT images were acquired and recorded to obtain three-dimensional datasets at discrete time points of 12, 24 and 48 h after irradiating HepG2 cells with 7.5 Gy. The cell migration distance in three-dimensional tissue models was quantified from images of radiation-induced and sham-irradiated cells, and this method was compared with the conventional Boyden chamber assay conducted at the same time points. SS-OCT measurements show that most cells were found near the gel surface, but a few were much deeper. Among those HCC cells with a high degree of migration capability, the mean migration distances at 24 h and 48 h were significantly greater for irradiated cells than for sham-irradiated cells (0.7 ± 0.23 mm versus 0.65 ± 0.26 mm at 24 h, P = 0.019 and 0.84 ± 0.30 mm versus 0.65 ± 0.524 mm at 48 h, P = 0.009). The results of radiation-enhanced invasion in HCC cells obtained by the non-invasive, quantitative SS-OCT method were consistent with those obtained using the traditional assay for measuring biological invasion.