Phosphorescent materials and devices with improved device manufacturing, fabrication, stability, efficiency, andor color. The high-voltage transformer is divided into a primary-side which is provided on the static gantry section and to which the output of a frequency converting circuit is supplied and a secondary-side which generates a high voltage. Since a swelling on the surface of the human body causes a path of the pulse signal to extend, the leak detector can detect, based on the extended signal path, that the needle has come off a blood vessel.