A novel high resolution micro-radiotherapy system for small animal irradiation for cancer research.

Micro-radiotherapy (micro-RT) system is specially designed for small animal (cancer cell) irradiation for basic and translational cancer research. We use carbon nanotube (CNT) field emission technology to develop a novel micro-RT system for image-guided high precision irradiation that is similar to the state of the art radiotherapy which our cancer patients receive today at mouse scale. Through the field emission control of its individually addressable x-ray pixel beams the micro-RT system electronically shapes the radiation field and forms intensity modulation pattern. In this paper, we present the development of a carbon nanotube field emission cathode array chip--a key component for our novel micro-RT system. The prototype micro-RT CNT field emission cathode array chip has 5 x 5 individually addressable cathode pixels that are 1 mm in diameter and 2 mm in pitch. An individual CNT cathode pixel is predicted to generate a dose rate in the order of 100 cGy/min at the center of the irradiated mouse based on our Monte Carlo simulation. The temporal and spatial resolutions of the micro-RT system are expected to be approximately ms level and < 2 mm respectively.