As the number of examinations in diagnostic radiology increases, direct or indirect medical radiation exposure for patients or workers has increased. To study the degree of medical radiation exposure, we measured and analyzed the lead apron’s shielding rate on direct radiation dose according to the quality of radiation beam. The distribution of space dispersal dose at X-ray exam was also measured at X-ray test on chest (100 kVp, 4 mAs, 100 mA) and L-spine AP (76 kVp, 200 mA, 32 mAs) to find out a better method to shield the worker’s radiation exposure. To measure the quality of X-ray in the scope of voltage generally used for X-ray exam in
the hospital, half-value layer was estimated at the voltages which is ranged from 40 to 120 kVp. Effective energy was estimated at the same voltage range and the result was 12.5 keV~39.9 keV. The result of measuring
radiation dose at increasing the voltage by 10 kVp each time on the range of 40~120 kVp, showed that the shielding rate of 0.50 mm Pb lead apron is superior to that of 0.25 mm Pb lead apron for all ranges of voltage.
The difference of shielding rate between 0.50 mm Pb and 0.25 mm Pb lead apron increased as the voltage increased. The maximum difference was 10.2 % at 120 kVp. In conclusion, the lead apron will be able to shield
the worker’s radiation exposure, especially for high voltage application for the exam, with understanding of space dispersal dose.