Waveguide delivery of x-rays for minimally invasive tumor therapy

Abstract

We are studying the potential use of x-rays, which are collected by non-imaging optics and delivered through stereotactically guided needles by hollow waveguides, for irradiation of tumors. X-rays have greater transparency in tissue than most longer optical wavelengths and may provide a more uniform dose to a tumor without harming normal tissue. Dosimetry is the key to minimal damage. We are investigating the use of fiber optics, tipped with calibrated scintillators and strategically located near the tumor, to measure the delivered dose. We are testing this procedure by using a 3 ns, variable accelerator voltage Fexitron 706 to produce approximately 50 mrads of x-ray energy. We concentrate, homogenize and inject this radiation into meter length, submillimeter hollow waveguides. We place the waveguides in a simulated tumor (a phantom breast). Streak and thermal cameras monitor the energy distribution during the irradiation by observing the distribution of energy as evidenced by fluorescence and heat. Once optimum exposure conditions of placement and dose are determined, tissue studies will begin.