Development and application of compact and on-chip electron linear accelerators for dynamic tracking cancer therapy and DNA damage/repair analysis

摘要

We are developing compact electron linear accelerators (hereafter linac) with high RF (Radio Frequency) frequency (9.3 GHz, wavelength 32.3 mm) of X-band and applying to medicine and non-destructive testing. Especially, potable 950 keV and 3.95 MeV linac X-ray sources have been developed for on-site transmission testing at several industrial plants and civil infrastructures including bridges. 6 MeV linac have been made for pinpoint X-ray dynamic tracking cancer therapy. The length of the accelerating tube is-600 mm. The electron beam size at the X-ray target is less than 1 mm and X-ray spot size at the cancer is less than 3 mm. Several hardware and software are under construction for dynamic tracking therapy for moving lung cancer. Moreover, as an ultimate compact linac, we are designing and manufacturing a laser dielectric linac of ~1 MeV with Yr fiber laser (283 THz, wavelength 1.06 urn). Since the wavelength is 1.06 urn, the length of one accelerating strcture is tens |im and the electron beam size is in sub-micro meter. Since the sizes of cell and nuclear are about 10 and 1 um, respectively, we plan to use this "On-chip" linac for radiation-induced DNA damage/repair analysis. We are thinking a system where DNA in a nucleus of cell is hit by ~1 μm electron or X-ray beam and observe its repair by proteins and enzymes in live cells in-situ. We try to apply this device to analyses of low dose radiation biological effect, especially Fukushima residents, and radiation sensitivity. Finally, we try to combine the pinpoint radiation therapy and radiation sensitivity analysis forward "Tailor-made Radiation Therapy".