Method and x-ray device using adaptable power source

A method described includes positioning an x-ray emitter at a treatment area, where the x-ray emitter is connected to a cable, setting a voltage source at a source voltage, and measuring a current through the x-ray emitter. The method may include comparing a current flowing through the emitter with a high limit and a low limit. The method further includes increasing the source voltage if the current is lower than the low limit. The method further includes decreasing the source voltage if the current is higher than the high limit. The method includes determining the high limit and the low limit based on the source voltage and the desired radiation. An apparatus of the invention includes an x-ray emitter, positionable in the passage, a cable connected to the x-ray emitter, a voltage source connected to the cable, and a current sensor for measuring the current. The apparatus may include a current comparison device for comparing the measured current with a high limit and a low limit, and further include a voltage source control device operatively connected to the current comparison device. A current integrator for integrating a current from the x-ray emitter may also be included.