High Dose Computed Tomography검사의 Exposure Dose 측정 및 평가

Evaluation of High dose Computed Tomography in Exposure dose Study

Purpose Charge of patient decreased on account of National Health Insurance benefit in CT examination. Scan time is reduced by generalization of spinal CT and utility of MDCT technic. Accuracy of diagnosis has improved because of up-to-date software. As a result, coefficient of utilization on CT examination increased and exposure dose is reduced by improved performance of detector and CT unit. It was necessary to use Thin slice in other to acquire a quantity of data but radiation hazard of adapted Multi-phase study increased. This Study evaluates exposure dose in CT examination. Objects and Methods CT head arteriography protocol is 20kVp, 100~300mAs, tube rotation time 0.5 or 1sec, total scan time 53sec, neck arteriography protocol is 120kVp, 150~300mAs, tube rotation time 0.5, 0.75 or 1sec, total scan time 67sec. CT OMU protocol is 120kVp, 120mAs, tube rotation time 1sec, total scan time 30sec. CT perfusion protocol is 80kVp, 200mAs, tube rotation time 1sec, total scan time 40sec. CT coronary artery protocol is 120kVp, pre : 20mAs, coronary artery : 600mAs, tube rotation time 0.5, or 0.37sec, total scan time 32sec. CT 3D intestine protocol is 120kVp, 200mAs, tube rotation time 0.5sec, total scan time 88sec. We located Ionization chamber at the center brain and abdomen acrylic and measure exposure dose. Results Exposure dose of CT head arteriography is 12.6R, exposure dose of CT neck arteriography is 23.83R, exposure dose of CT OMU is 12.6R, exposure dose of CT coronary artery is 6.15R, exposure dose of CT 3D intestine is 9.68R. We measured 5 times multi-phase study of CT neck arteriography, CT 3D intestine : 5 times, CT OMU : 2 times, CT perfusion : 2 times, CT coronary artery : 3 times Conclusion Exposure dose of CT head arteriography is 12. 6R which is maximum value and exposure dose of CT OMU is 12.6R which is minimum value. there is not only benefit but also a loss