Area-Addressable ZnO Nanowire-Based Cold Cathode Transparent Flat-Panel X-ray Sources for Visual Intraoperative Radiotherapy

X-ray intraoperative radiotherapy (IORT) is an important method for treating specific tumors. Area-addressable transparent flat-panel X-ray source can achieve selective-area radiotherapy and direct optical imaging guide, which could enhance the capability of the current IORT technique and has not been reported to date. In this paper, an area-addressable transparent flat-panel X-ray source was realized using zinc oxide (ZnO) nanowire field emitter arrays (FEAs) and an indium tin oxide (ITO) transparent anode. Planar-gate ZnO nanowire FEAs were fabricated and demonstrated a good addressing performance and uniform electron emission characteristics. A maximum anode current density of 884 μA/cm² was measured at one area under gate-addressed emission conditions, and the current fluctuation was approximately 5.8% in 2.5 h. The planar-gated ZnO nanowire FEAs were applied in the transparent flat-panel X-ray source. A radiation dose rate of 5.76 mGy/s was measured at the anode surface of the flat-panel X-ray source under the application of 40 kV anode voltages. The reported X-ray source device has potential applications in advanced intraoperative radiotherapy.