Observational phantom study.This study aimed to evaluate the radiation exposure dose of practitioner's hands when performing C-arm guided procedures and to determine the usefulness of our newly designed radiation shielding device.C-arm guided procedures including lumbar transforaminal epidural steroid injections (TFESIs) are commonly used for pain control induced by lumbar radiculopathy. The practitioner's hands are vulnerable to radiation exposure because of the long exposure time and short distance from the radiation resource. No studies to date have reported the cumulative exposure of the physician's hands according to location and exposure time.Using a chest phantom irradiated with X-rays under lumbar TFESI conditions, cumulative scatter radiation dose was measured at 36 points using a dosimeter. The measurements were checked at 1, 3, 5, 10 minutes of radiation exposure. The experiment was repeated using our newly designed shielding device.Significant radiation accumulation was observed in the field where the practitioner's hands might be placed during C-arm guided procedures. The further the distance from the radiation resource and the shorter the exposure time, the smaller was the cumulative radiation expose dose. The new shielding device showed an excellent shielding rate (66.0%-99.9%) when the dosimeter was within the shielding range. However, at some points, increased accumulated radiation exposure dose was observed, although the dosimeter was within the range of the shielding device.To reduce radiation exposure of the practitioner's hands when performing C-arm-guided procedures, the radiation exposure time should be decreased and a greater distance from the radiation resource should be maintained. When using our shielding device, placing the hand close to the device surface and minimizing the time using fluoroscopy minimized the radiation exposure of the hand.