Dual Source CT에서 Selective Photon Shield를 사용한 Material Separation 영상의 quality와 선량 비교에 관한 실험

Comparison Material Separated image and Dose that used Selective Photon Shield in Dual Source CT

목적 이 연구의 목적은 Dual Source CT에서 Selective Photon Shield를 사용한 material separation 영상의 quality와 선량을 비교하기 위함이다. 대상 및 방법 Somatom Definition와 Definition flash을 이용하여 영상의 quality는 lung-chest phantom을 이용하여 검사하여 비교하였고, 선량은 rando phantom(Model ART-200-5, Fluke Biomedical)에 glass dosimeter(GD352M, 12mm, Dose ACE, Japan) 10개를 삽입하여 얻은 값의 평균값을 비교하였으며, material separation은 rando phantom을 통해 얻은 data를 bone removal processing 하여 육안으로 비교하였다. 결과 영상의 noise index는 definition 장비에서는 목 부위에서는 37.7, 흉골부위에서는 36.2, 척추 앞쪽 부위에서는 46.5 값이 나왔다. Definition flash 에서는 순서대로 15.5, 14.9, 22.0으로 Definition 보다 낮은 값이 나왔다. 선량에서도 Definition에서는 7.096mGy이 나왔고, Definition flash에서는 6.354mGy로 더 낮게 측정되었다. Material separation 비교는 Definition 장비가 Definition flash 보다 더 좋은 효과를 보였다. 결론 선량과 noise 측면에서는 Definition flash가 더 좋았으나, Material separation에서는 Definition flash가 더 좋았다. 이 결과를 통해 어느 한 장비가 좋다기 보다는 두 장비의 장점을 비교하여 환자에 따른 적절한 장비 선택이 있어야 하겠다.

I. Purpose Purpose of this study was to compare the material separated image and dose that used Selective Photon Shield in Dual Source CT. II. Meterial and Methods The study has been examined by Somatom Definition and Somatom Definition Rash that have same parameter except for some parameter. Lung-chest phantom was used to measure image quality. Also rando phantom(Model ART-200-5, Fluke Biomedical) was used to analyze absorbed dose and material separation. Noise measured for evaluating image quality andabsorbed dose evaluated by ten glass dosimeters(GD352M, 12mm, Dose ACE, Japan) whichwere put in the rando phantom for evaluation of absorbed dose. III. Result Noise index of Definition was measured at Neck, p-ara sternum and Anterior of spine. Each noise index vale was 37.7, 36.2, 46.5. Also Definition Flash was 15.5, 14.9 and 22.0. Definition Flash Noise index was lower than Definition Flash. Absorbed dose in Definition was 7.10mGy and Definition Flash was 6.35mGy. It shows that Definition Flash have lower Absorbed dose than Definition. In result of material separation, Definition has a good material separation than Definition Flash through bone removed image that was scanned by each machine. IV. Conclusions Dose and noisein Definition Flash are better Definition, but material separation effect not good than Definition. Through these results, we should decide proper equipment which is suitable for patient condition.