DR System에서 L-Spine 검사 시 HVT(High Voltage Technique)의 유용성

Utility of HVT(High Voltage Technique) in DR System When L-spine is inspected

Purpose : The analogue simple radio- graphs are gradually replaced with digital radio- graphs and image quality is improving. However because there is no recommendation for digital radiography condition, method of analogue simple radio-graphs is used for digital radiography. We studied the radio- graphs condition which are compared image quality of each different exposure condition by using High Voltage technique. Materials and methods : We used modem DR equipment(Philips Digital Diagnost) and the Dosimeter-FLUKE biomedical victoreen nero max model 8000, Ion Chamber-30cc to get the photographs of human like body phantom. Experimental methods 1. When L-spine was inspected, the value of EI was 320 when 77kV, 25mAs. To find proper value of EI(200~400), we changed the range of tube voltage 77 to g) kV and tube current 8 to 40mAs. 2. Using EI value between 200 to 400, We found the dGycm² expressed the image resolution through the presetting table that was consist of DAP(Dose area product), human-like body phantom and resolution chart. 3. The quality of image is calculated by two radiologists and 8 radio-graphers who have 5 years experience. They count the number of circle in the image when is displayed from different exposure conditions. 4. They measured exposure dose as five times exposure of phantoms through the condition table which was set before. Results : When reference condition of L-spine was 77kV and 25mAs, exposure dose was 59 mGy, DAP was 29.15dGycm² When 96kV, 8mAs was corresponded to 32 mGy, DAP 9.09 dGycm² that was similar image quality with reference condition. Conclusion : L-spine which is using high voltage seems to be promising method may take effect to reduce exposure dose of radiation without lowing quality of radio image and it’s almost the same compared with a conventional condition. Therefore We strongly recommend high voltage technique which is reduced medical exposure dose.