Detailed information on the location and the size of tumor cells circulating through lymphatic and blood vessels is useful to cancer diagnosis. Metastasis of cancers to other non-adjacent organs is reported to cause 90% of deaths not from the primary tumors. Therefore, effective detection of circulating tumors cells (CTCs) related to metastasis is emphasized in cancer treatments. With the use of synchrotron X-ray micro-imaging techniques, high-resolution images of individual flowing tumor cells were obtained. Positively charged gold nanoparticles (AuNPs) which were inappropriate for incorporation into human red blood cells were selectively incorporated into tumor cells to enhance the image contrast. This approach enables images of individual cancer cells and temporal movements of CTCs to be captured by the high X-ray absorption efficiency of selectively incorporated AuNPs. This new technology for in vivo imaging of CTCs would contribute to improve cancer diagnosis and cancer therapy prognosis.
Keywords: X-ray imaging; cancer cell; circulating tumor cell; gold nanoparticle.