Hypofractionated stereotactic body radiotherapy treatments (SBRT) have improved patient treatment outcomes. Extensive studies were performed investigating how vascular changes during treatment affect its efficacy. Unfortunately, histology is unable to perform non-invasive longitudinal assessments by directly measuring blood perfusion. Here, we present a novel preclinical theranostic μCT-guided irradiator/Fluorescence Molecular Imager, designed to perform a fast, non-invasive, and longitudinal assessment of tumor vascular response (TVR) to targeted radiotherapy. Our technique allows rapid assessment of spatiotemporal differences in indocyanine green (ICG) kinetics in tumors using principal component (PC) analysis, before and after tumor irradiation. Results show that changes were observed in the normalized first and second PC feature pixel values (p=0.0559, 0.0432 paired t-test). Moreover, we implemented a fast PC-based classification algorithm that yields spatially-resolved TVR maps. Our first-of-its-kind theranostic system, allowing automated assessment of TVR to SBRT, will be used to better understand the role of tumor perfusion in metastasis and tumor control.
|