中华放射医学与防护杂志
中華放射醫學與防護雜誌
중화방사의학여방호잡지
Chinese Journal of Radiological Medicine and Protection
2013年
1期
91-94
,共4页
高燕莉%张镭%刘晓娟%翟仁友
高燕莉%張鐳%劉曉娟%翟仁友
고연리%장뢰%류효연%적인우
肺部疾病%容积高分辨CT%体模%低剂量扫描
肺部疾病%容積高分辨CT%體模%低劑量掃描
폐부질병%용적고분변CT%체모%저제량소묘
Lung diseases%Volumetric high-resolution CT%Phantoms%Low dose scanning
目的 研究肺部容积高分辨CT(volumetric high-resolution CT,VHRCT)的低剂量扫描方案,评价其诊断价值.方法 采用120 kV和10～250 mAs对Catphan 500体模行VHRCT扫描,层厚0.625 mm,记录图像的空间分辨力、密度分辨力、噪声及扫描剂量,制定低剂量VHRCT的扫描方案；105例在本院行常规剂量VHRCT检查的肺弥漫病变患者,复诊时行低剂量VHRCT,比较常规剂量与低剂量VHRCT对于肺弥漫病变的显示情况.结果 体模研究中,管电压120 kV,管电流120～250 mAs时,VHRCT图像的空间分辨力均为9 LP/cm；低于120 mAs时,随着管电流降低,VHRCT图像的空间分辨力和密度分辨力下降而噪声增加.临床研究中,对于肺弥漫病变各种征象的显示,低剂量VHRCT(120 kV,120 mAs)与常规剂量VHRCT(120 kV,250 mAs)比较差异无统计学意义(P＞0.05).扫描剂量较常规VHRCT降低52％.结论 采用120 kV和120 mAs行低剂量VHRCT,可以在保持图像的分辨能力及诊断价值的前提下显著降低放射剂量,其取代常规剂量VHRCT具有可行性.
目的 研究肺部容積高分辨CT(volumetric high-resolution CT,VHRCT)的低劑量掃描方案,評價其診斷價值.方法 採用120 kV和10～250 mAs對Catphan 500體模行VHRCT掃描,層厚0.625 mm,記錄圖像的空間分辨力、密度分辨力、譟聲及掃描劑量,製定低劑量VHRCT的掃描方案；105例在本院行常規劑量VHRCT檢查的肺瀰漫病變患者,複診時行低劑量VHRCT,比較常規劑量與低劑量VHRCT對于肺瀰漫病變的顯示情況.結果 體模研究中,管電壓120 kV,管電流120～250 mAs時,VHRCT圖像的空間分辨力均為9 LP/cm；低于120 mAs時,隨著管電流降低,VHRCT圖像的空間分辨力和密度分辨力下降而譟聲增加.臨床研究中,對于肺瀰漫病變各種徵象的顯示,低劑量VHRCT(120 kV,120 mAs)與常規劑量VHRCT(120 kV,250 mAs)比較差異無統計學意義(P＞0.05).掃描劑量較常規VHRCT降低52％.結論 採用120 kV和120 mAs行低劑量VHRCT,可以在保持圖像的分辨能力及診斷價值的前提下顯著降低放射劑量,其取代常規劑量VHRCT具有可行性.
목적 연구폐부용적고분변CT(volumetric high-resolution CT,VHRCT)적저제량소묘방안,평개기진단개치.방법 채용120 kV화10～250 mAs대Catphan 500체모행VHRCT소묘,층후0.625 mm,기록도상적공간분변력、밀도분변력、조성급소묘제량,제정저제량VHRCT적소묘방안；105례재본원행상규제량VHRCT검사적폐미만병변환자,복진시행저제량VHRCT,비교상규제량여저제량VHRCT대우폐미만병변적현시정황.결과 체모연구중,관전압120 kV,관전류120～250 mAs시,VHRCT도상적공간분변력균위9 LP/cm；저우120 mAs시,수착관전류강저,VHRCT도상적공간분변력화밀도분변력하강이조성증가.림상연구중,대우폐미만병변각충정상적현시,저제량VHRCT(120 kV,120 mAs)여상규제량VHRCT(120 kV,250 mAs)비교차이무통계학의의(P＞0.05).소묘제량교상규VHRCT강저52％.결론 채용120 kV화120 mAs행저제량VHRCT,가이재보지도상적분변능력급진단개치적전제하현저강저방사제량,기취대상규제량VHRCT구유가행성.
Objective To explore the optimal low-dose protocol of volumetric high-resolution CT (VHRCT) of the lung and evaluate its diagnostic value.Methods Catphan phantom were scanned using GE Lightspeed VCT with different parmeters from 120 kV,10 mAs to 120 kV,250 mAs in 10 mAs increments.Other parameters included 0.969 pitch,20 mm scan coverage,0.625 mm collimation and 30 cm display field of view and bone recon kernel.The spatial and density resolution,noise and radiation dose of each scanning were measured to determine the low-dose VHRCT protocol.In clinical study,105 patients with diffuse lung diseases underwent standard-dose VHRCT with 120 kV,250 mA according to the clinical needs.Low-dose VHRCT was performed with 120 kV,120 mAs in follow-up.Two radiologists who were unaware of the CT technique reviewed randomized images for the detail of diffuse lung diseases,including linear or reticular opacities,micro-nodules or tree-in-bud patterns,bronchiolectasis,ground-glass opacities and emphysema using a 4-point scale.Results In phantom study,the spatial-resolution maintained at 9 LP/cm from 250 mAs to 120 mAs.Below 120 mAs,the spatial-resolution and density-resolution decreased and noise increased with the decrease of tube-current.In clinical study,there were no statistical differences between standard-dose and low-dose VHRCT in demonstrating the detail of diffuse lung diseases(P ＞0.05).The CTDIvol was 23.44 mGy at 250 mAs and 11.25 mGy at 120 mAs,with 52％dose reduction by low-dose VHRCT.Conclusions Low-dose VHRCT at 120 kV,120 mAs offers maximum dose reduction without compromising spatial resolution and diagnostic value.
