High-speed dental radiography achieved with a kilohertz-range pulsed x-ray generator

The development of a high-intensity kilohertz-range pulsed x-ray generator and its application to dental radiography are described. The pulsed x-ray generator consisted of the following major components: a constant high-voltage power supply, a high-voltage main condenser, a hot-cathode triode, a DC power supply for the filament (hot cathode), and a grid controller. The main condenser of 0.5 microF-100 kV in the pulser was charged from 50 to 70 kV by the power supply, and the electric charges in the condenser were discharged to the triode by the grid controller. To be exact, the tube voltage decreased during the discharging for generating pulsed x-rays, yet the maximum value was equivalent to the initial charging voltage of the main condenser. The maximum values of the tube current and the repetition rate were about 0.5 A and 30 kHz, respectively. The pulse width of the x-rays ranged from approximately 20 to 400 micros, and the x-ray intensity with a charging voltage of 70 kV and a total resistance of 5.1 MΩ was about 0.83 microC/kg at 1.0 m per pulse. Using this generator, high-speed dental radiography, e.g., delayed radiography and multiple-shot radiography, was performed