Generation of continuous and pulsed diagnostic imaging x-ray radiation using a carbon-nanotube-based field-emission cathode

Abstract

X-ray radiation is widely used in medical and industrial applications. The basic design of the x-ray tube has not changed significantly in the last century. In this paper, we demonstrate that medical diagnostic x-ray radiation can be generated using a carbon nanotube (CNT) based field-emission cathode. The device can readily produce both continuous and pulsed x-ray with a programmable waveform and repetition rate. A total emission current of 28 mA was obtained from a 0.2 cm 2 area CNT cathode. The x-ray intensity is sufficient to image human extremity at 14 kVp and 180 mAs. Pulsed x-ray with a repetition rate greater than 100 kHz was readily achieved by programming the gate voltage. The CNT-based cold-cathode x-ray technology can potentially lead to portable and miniature x-ray sources for industrial and medical applications.

Carbon Nanotubes for Biomedical Applications

“…The advantages of CNT-based x-ray devices are fast response time, fine focal spot, low power consumption, possible miniaturization, longer life, and low cost. Besides, it minimizes the need of cooling required by the conventional method [152], [158], [159]. Miniaturized x-ray devices can be inserted into the body by endoscopy to deliver precise x-ray doses directly at a target area without damaging the surrounding healthy tissues, as malignant tumors are highly localized during the early stage of their development.…”

High-Resolution CT for Small-Animal Imaging Research

“…More recently, Cao et al have investigated the use of a compact field emission microfocus x-ray source based on carbon nanotube (Cao et al, 2009(Cao et al, , 2010. In this type of source, the metal filament cathode is replaced by a field emission cathode that is capable of emitting electrons at room temperature with voltage-controlled output current (Yue et al, 2002). The authors obtained stable emission of x-rays at 50 kV and 1 mA, with pulse length down to 20 ms and with a focal spot size of 100 mm.…”

Control of ZnO nanowire arrays by nanosphere lithography (NSL) on laser-produced ZnO substrates

“…One such potential application is in the development of new field emission (FE) sources for use as miniature X-ray sources or flat panel displays [1,2]. Zinc oxide (ZnO) is a promising candidate for such devices which has applications in various technologies [3] and in particular is well suited for FE applications.…”