Characterization of a carbon nanotube-based X-ray microbeam generation system for low-dose radiobiology

We developed a carbon nanotube (CNT)-based field emission system to generate low-dose X-ray microbeams, aimed at radiobiological studies requiring precise dose control. The CNT emitter was directly synthesized on a metal alloy substrate in a radial pattern to enhance field emission performance, achieving a stable emission current of 3 mA at −14 kV in both continuous and pulsed modes. Simulations and experiments confirmed that an emitter-to-window distance of 20 mm provided the highest electron collision efficiency (16.14 %) with minimal scattering. A linear relationship between input power (0.5–70 W) and radiation dose (0.01–3.2 cGy) enabled predictable and adjustable dose delivery. Moreover, the pulsed irradiation capability of the system facilitated temporal modulation through different duty cycles. Cell viability studies (1–10 cGy) revealed distinct responses to continuous versus pulsed exposure, underscoring the potential of the system for investigating adaptive mechanisms and hormesis effects in low-dose radiation biology. This compact, CNT-based X-ray source offers precise spatiotemporal dose control in dual operational modes, opening new opportunities for systematically exploring radiobiological phenomena under low-dose conditions.