Safety evaluation of mobile X-ray equipment using super-capacitor.

In this study, we designed mobile X-ray equipment that generates high-power X-rays, using an internal power source by means of a super-capacitor, and evaluated its safety. The proposed X-ray equipment uses the charging voltage of a battery to store high density energy, supplementing the electric charge of the super-capacitor, which can instantly release a large amount of energy. Further, pulse frequency modulation was applied to produce high voltage and thereby improve energy efficiency. The developed mobile X-ray equipment enables to generate an output of 30 kW and, therefore, can be applied to many diagnostic fields. In addition, various devices and control circuits were employed to ensure convenience and safety of using the equipment in clinical applications. This study analyzed the error ranges regarding tube voltage, tube current, irradiation time, coefficient variation, half-value layer, and the output characteristics. The results showed that the proposed X-ray equipment was able to generate 800 mR X-ray power under the condition of 30 kW. The coefficient variation was less than 0.05 at all measurement points, which indicates that it is possible to generate the equal amount of X-ray when the driving conditions are same. Results also showed 51.25% of transmittance at 3.5 mmAL in the case of the wire, which is thicker than a common reference of 2.3 mmAL and indicates that this new mobile equipment is possible to generate X-rays with relatively high permeability. In conclusion, the findings in this study suggest that the new equipment can generate consistent high-power X-rays and, therefore, can be used safely by minimizing unnecessary re-taking of images and radiation exposure.