수술 중 C-Arm Neutral AP 검사 시 조절인자에 따른피폭선량 및 화질비교 (L-Spine AP검사를 기준으로)

Abstract

Purpose: Time of operation has been reduced and accuracy of operation has beenimproved since C-arm, which offer real-time image of patient, was introduced in operation room. However, because of the contamination of patient, C-arm could not be used more appropriately. Therefore, this study is to know factors of controlling exposure dose, image quality and theexposed dose of health professional in operation room. Materials and methods: Height of Wilsonframe (bed for operation) was fixed at 130 cm. Then, Model 76-2 Phantom, which was set byassembling manual of Fluke Company, was set on the bed. Head/Spine Fluoroscopy AEC modewas set for exposure condition. According to detector size of C-arm, the absorbed dose per minwas measured in the 7 steps OFD (cm) from 10 cm to 40 cm (10, 15, 20, 25, 30, 35, 40 cm). Ineach step of OFD, the absorbed dose per min of same diameter of collimation was measured. Moreover, using Nero MAX Model 8000, exposure dose per min was measured according to 3 stepof distance from detector (20 cm, 60 cm, 100 cm). Finally, resolution was measured by CDRH DiscPhantom and magnification of each OFD was measured by aluminum stick bar. Result: Accordingto detector size of C-arm, difference of absorbed dose shows that the dose of 20 cm OFD is 1.750times higher than the dose of 40 cm OFD. It means that the C-arm, which has smaller size ofdetector, shows the bigger difference of absorbed dose per min (p<0.05). In the differenceofabsorbed dose in the same step of OFD (from 20 cm to 40 cm), the absorbed dose of 9 inch detector C-arm was 1.370 times higher than 12 inch’ s (p<0.05). When OFD was set to 20 cm OFD, theabsorbed dose of non-collimation case was approximately 0.816 times lower than the absorbeddose of collimation cases (p<0.05). When the distance was 20 cm from detector, exposed does in cludes first-ray and scatter-ray. When the distance was 60 cm and 100 cm from detector, exposeddoes includes just scatter-ray. So, there was the 2.200 times difference of absorbed does. Finally,when OFD was increased, spatial resolution was 4 to 5 step was increased. However, low contrastresolution was not relative. Moreover, there was 1.363 times difference of magnification (p<0.05). Conclusion: When C-Arm is used, avoiding contamination of patient is more important factor thanreducing exposed dose of health professional in operation room. Just controlling exposure time isjust way to reduce the exposed does of workers. However, in the case, non-probability influencecould be occurred. Therefore, this study proved that the exposed dose will be reduced if the factorssuch as using small detector size of C-arm, setting OFD from 20 cm to 25 cm and non-collimating. Moreover, dose management of C-arm in the non-interesting area will be considered additionally.