The NOMAD and NOMAD Pro are handheld X-ray units that have fixed shields against backscatter radiation. The DEXCO ADX4000W and DEXCO DX3000 include these shields as optional, detachable accessories. For this study, the objective of which was to clarify the characteristics of Portable X-ray Units, we evaluated the characteristics of output and measured the changes in air kerma of stray radiation from four portable intraoral X-ray units with/without a shield.

 Scattered radiation, generated from an IEC CT dosimetry head phantom and the X-ray units, was measured using the 350 cc ionization chamber.

 By using a shield against backscatter radiation, radiation exposure in the work space was reduced to about one-third.

 This study showed that the use of a shield against backscatter radiation was effective in reducing an operator's exposure to radiation.