조영제와 생리식염수 혼합물을 이용한 표면선량 감소에 관한연구

• 영문명: A study on surface absorbed dose reduction by using contrast media and normal saline solution mixture
• 발행기관: 대한CT영상기술학회
• 저자명: 고주성(Ju seong Ko) 임상묵(Sang muk Yim) 강화원(Hwawon Gang) 김대현(Dae hyeon Kim)
• 간행물 정보: 『대한CT영상기술학회지』대한전산화단층기술학회지 제17권 제2호, 37~45쪽, 전체 9쪽
• 주제분류: 의약학 > 방사선과학
• 파일형태: PDF
• 발행일자: 2015.09.30

국문 초록

목적 : 조영제와 생리식염수를 섞어서 조영제 농도를 달리해 차폐물을 제작하여 조영제 농도에 따른 표면선량 차폐효과에 대해 알아보고자 하였다. 대상 및 방법 : CT장비는 SOMATOM Definition(Siemens, Germany)를 사용하였고, 선량의 측정을 위해 Atom Phantom(CIRS)과 형광유리소자(GD-352M:Chiyoda Technol Japan)을 사용하으며, 선량판독기(FDG-1000;AGC, Techno Glass, Shizuoka, Japan)를 이용하였다. 화질평가를 위해 AAPM Phanrom(Model 76-410, Nuclear Associates LTD)을 사용하였다. 기존의 차폐물질인 BISMUTH(F&L Medical Products co, 0.060mmpb equivalent, USA)와조영제와 생리식염수를 혼합하여 제작한 조영제 200 cc+생리식염수 200 cc, 조영제 100 cc+생리식염수 300cc, 조영제 50 cc+ 생리식염수 350cc, 조영제 25 cc+생리식염수 375 cc, 조영제 10cc+생리식염수 390 cc을 비교하였.다 조영제 혼합차폐물을 Atom 팬텀의 흉부위에올려놓고 형광유리선랑계를 양측 유두부 위치와 폐야에 위치시켜서 각각 선량을 측정하였으며, 비교를 위해 BISMUTH 사용했을 때와 차폐체 없을때 와의 선량을 비교 측정하였다. 피사체와차폐물과의 거리를 0 cm, 0.7 cm, 1.4 cm, 2.1 cm으로 변화시켜 거리에 따른 선량변화를 측정하였고 Image Quality를 측정하기 위해 AAPM Phantom을 이용하여 위 실험과 같은 방법으로 노이즈와 균일도를 측정하였다. 결과 : bone plus algorithm을 대조군으로 환자데이터를 분석하였다. soft tissue에서 SD값이 ultra algorithm은 FBP와 ASIR30% 모두 bone plus algorithm과 차이가 없었다. edge algorithm은 SD값이 FBP와 ASIR30% 각각 28.78%, 34.63% 증가했다. bone어|서 SD값이 ultra algorithm은 FBP와 ASIR30% 가각 18.88%, 19.78% 증가했고, edge algorithm은 FBP와 ASIR30% 각각 10%, 9.1% 감소했다. 공간분해능과 선예도 측정결과 bone plus, edge, ultra algorithm의 MTF50% 값은 FBP에서 각각 4.28, 0.62, 5.64였고, ASIR30%는 4.39, -3.77, 6.17이었다. MTF10%값은 FBP에서 6.50, 5.85, 10.01 이었고, ASIR30%는 6.91, 5.74, 21.98이었다. 측정결과 ultra algorithm의 공간분해능과 선예도가 가장 좋았다. 결론 : Ultra algorithm은 기존의 bone plus, edge algorithm과 비교했을 때 저주파영역의 노이즈 증가없이 고주파영역만 강조하면서 영상의 화질 또한 우수하다는 것을 알 수 있었다. 임상 Temporal bone CT검사에서 ultra algorithm은 bone plus algorithm과 비교하여 적절히 사용한다면 매우 유용할 것이라 사료된다.

영문 초록

Purpose : The purpose of this study lies in examining the screening effect of surface absorbed dose based on concentration of contrast media by manufacturing a screen with different contrast media concentration by mixing contrast media and physiological saline solution. Materials & Methods : SOMATOM Definition (Siemens, Germany) was used for CT device and Atom Phantom (CIRS) and fluorescent glass element (GD-352M;Chiyoda Technol Japan) were used for measurement of dose. Also, dosimeter (FDG-1000;AGC, Techno Glass, Shizuoka, Japan) was used to measure absorbed dose and AAPM Phantom(Model 76-410, Nuclear Associates LTD) was used for image quality assessment. The comparison was conducted with mixture of previous screen BISMUTH (F&L Medical Products co, 0.060mmpb equivalent, USA) and contrast media 200 cc + normal saline solution 200 cc, contrast media 100 cc + normal saline solution 300cc. contrast media 50 cc + normal saline solution 350 cc. contrast media 25 cc + normal saline solution 375 cc, and contrast media 10 cc + normal saline solution 390 cc manufactured with mixture of contrast media and normal saline solution. The absorbed dose was measured by fluorescent glass dosimeter after placing contrast media mixed screen to the thorax of atom phantom and fluorescent glass dosimeter to the location of both nipples and lung field. Comparative measurement was conducted in order to compare the dose with the use of BISMUTH and without use of screen. The changes in doses accordingly with distance were measured by changing distance between the subject and screen into 0cm. 0.7cm, 1.4cm, and 2.1 cm and noise and uniformity were measured with same method as above experiment using AAPM Phantom for the measurement of image quality. Result : Although reduction effect of surface absorbed dose was greatest with the use of contrast media 200 cc + normal saline solution 200 cc presenting 4.2 mGy, it has exceeded allowable range when measuring the uniformity. Although there was two-fold increase in surface absorbed dose for screen manufactured with made of contrast media 25cc + normal saline solution 375 cc in comparison with contrast media 200 cc+ normal saline solution 200 cc, the uniformity was measured within allowable range presenting the surface absorbed dose of 8.1 mGy. Also, there was surface absorbed dose reduction of 27% compared to surface absorbed dose 11.0 mGy scanned without screen. There were little changes in surface absorbed doses based on changes in distance between contrast media mixed screen and subject. In regards to noise assessment, it was measured to be the lowest presenting 11.7 without screen and the highest presenting 29.3 with the use of contrast media 200 cc+ normal saline solution 200 cc. With the screen, it was measured to be the lowest presenting 14.7 for contrast media 10 cc + normal saline solution 390 cc. Conclusion : Surface absorbed dose reduction effect of 27% could be acquired compared to previous screen BISMUTH and uniform CT number could be obtained with the use of contrast media mixed screen 25 cc + 375 cc. It is believed that contrast media mixed screen will be of great assistance to surface absorbed dose reduction in case there is no previous screen.

목차

Abstract

Ⅰ. 서론

Ⅱ. 대상 및 방법

Ⅲ. 결과

Ⅳ. 고찰

Ⅴ. 결론

참고문헌

초록

키워드

temporal bone CT algorithm FBP ASIR