CAJ | 학술논문

目的探讨HT的MVCT扫描剂量率波动和不同扫描精度选择对图像CT值及噪声的影响.方法 MVCT在不同剂量率和扫描层厚下扫描带各种密度棒的水模体,对应各密度棒的CT值得出各自条件下的IVDT曲线进行对比.MVCT在不同剂量率和扫描层厚下扫描带有均匀密度棒的水模体,测量不同扫描条件下均匀水模体中的CT图像噪声.对结果进行方差及相关性分析.结果不同扫描剂量率下对CT值影响显著(P=0.000),各密度棒对应CT值的变化大小与密度呈正相关(R2 =0.846),既高密度物质的CT值受的影响较大.不同剂量率对噪声也有显著影响,扫描剂量率越低图像噪声越大(P=0.000).2、4、6 mm扫描层厚对CT值(P=1.000)及图像噪声(P=0.667)无显著影响.结论 MVCT剂量率改变会引起CT值及图像噪声改变,在临床中应定期对MVCT剂量率及IVDT曲线稳定性进行监测,以保证ART计划中MVCT图像剂量计算的准确.
목적 탐토HT적MVCT소묘제량솔파동화불동소묘정도선택대도상CT치급조성적영향.방법 MVCT재불동제량솔화소묘층후하소묘대각충밀도봉적수모체,대응각밀도봉적CT치득출각자조건하적IVDT곡선진행대비.MVCT재불동제량솔화소묘층후하소묘대유균균밀도봉적수모체,측량불동소묘조건하균균수모체중적CT도상조성.대결과진행방차급상관성분석.결과 불동소묘제량솔하대CT치영향현저(P=0.000),각밀도봉대응CT치적변화대소여밀도정정상관(R2 =0.846),기고밀도물질적CT치수적영향교대.불동제량솔대조성야유현저영향,소묘제량솔월저도상조성월대(P=0.000).2、4、6 mm소묘층후대CT치(P=1.000)급도상조성(P=0.667)무현저영향.결론 MVCT제량솔개변회인기CT치급도상조성개변,재림상중응정기대MVCT제량솔급IVDT곡선은정성진행감측,이보증ART계화중MVCT도상제량계산적준학.
Objective To study the CT number and noise of HT MVCT on different dose rate and scanning thickness.Methods The CT number of different relative electron density were measured in the MVCT image of Cheesephantom with tissue substitute plugs scanned with different dose rate and slice thickness.The physical density corresponding to the CT number was plotted as the image value to density table (IVDT).The noise was measured in the MVCT image of Cheesephantom with solid water plugs scanned with different dose rate and slice thickness.Results There was a significant different of the CT number of the plugs with different dose rates (P =0.000),it shows a positive correlation between the varied CT number and density (R2 =0.846),there is larger impact on the high density number.There was still a significant effect on the noise with different dose rate (P =0.000 density),the noise increase as the dose rate decrease.There was no significant effect on IVDT (P =1.000) and noise (P =0.667) with different slice thickness.Conclusions The CT number and the noise vary with the dose rate,the QA of MVCT should be performed regularly to assure the quality of image and the accuracy of dose calculating on MVCT in adaptive.