兒童體模胸部雙源CT掃描低劑量實(shí)驗(yàn)性研究
發(fā)布時(shí)間：2018-11-21 13:12
【摘要】：目的:兒童在影像學(xué)檢查中單位體積所受X線劑量要遠(yuǎn)高于成年人,而且兒童對(duì)X線輻射的較成人更敏感,相同的輻射劑量下,兒童所受的損傷要遠(yuǎn)大于成年人,所以降低兒童在影像檢查中所受的X線劑量是一項(xiàng)非常有意義的工作,我們進(jìn)行這次實(shí)驗(yàn)的目的是在滿足圖像質(zhì)量診斷要求的前提下,盡可能的降低患兒所受的輻射劑量,研究產(chǎn)生最小輻射劑量且滿足診斷需要的掃描條件。方法:本次實(shí)驗(yàn)在雙源CT下進(jìn)行,設(shè)備使用西門(mén)子Definition Flash雙源CT,并選擇Flash Spiral模式進(jìn)行胸部掃描,檢查中開(kāi)啟CARE Dose4D技術(shù)。體模采用型號(hào)為76-414-4150,由上海滋源貿(mào)易公司經(jīng)銷的美國(guó)FLUKE福祿克公司生產(chǎn)的體模。實(shí)驗(yàn)按管電壓的不同進(jìn)行分組,60kV、80kV、100kV、120kV各一組,管電流設(shè)為自動(dòng)毫安秒,設(shè)定螺距5.0,層厚為5.0 mm,重建圖像采用SAFIRE3迭代技術(shù)。將體模按照胸部掃描的標(biāo)準(zhǔn)體位進(jìn)行擺放,每個(gè)條件下掃描50次,每次對(duì)體模厚度進(jìn)行調(diào)整以模擬不同體型的患兒。將掃描結(jié)果傳輸至工作站以待下一步處理。圖像分析:(1)圖像重建及客觀評(píng)價(jià)標(biāo)準(zhǔn):用AW4.6工作站(GE HeahhCare,USA)對(duì)圖像進(jìn)行重建。應(yīng)用信噪比來(lái)進(jìn)行圖像的客觀評(píng)價(jià),具體操作方法為,體模模擬心臟中心位置設(shè)為感興趣區(qū),面積為3.0mm2,測(cè)量并記錄這一區(qū)域的SD值和CT值。圖像信噪比(SNR)的計(jì)算方法為:SNR=相應(yīng)感興趣區(qū)(ROI)的CT值/噪聲SD。(2)主觀評(píng)價(jià)標(biāo)準(zhǔn):由兩個(gè)副高以上職稱的高年資影像醫(yī)師根據(jù)臨床經(jīng)驗(yàn)對(duì)圖像質(zhì)量進(jìn)行評(píng)價(jià)打分。將圖像質(zhì)量從差到優(yōu)分為1~5分,具體標(biāo)準(zhǔn)為:1分,正常的組織結(jié)構(gòu)顯示不清楚,邊緣模糊不清,完全無(wú)法區(qū)分組織結(jié)構(gòu)關(guān)系;2分,組織結(jié)構(gòu)比較模糊,存在一定的偽影,不能區(qū)分結(jié)構(gòu)關(guān)系;3分,組織結(jié)構(gòu)邊緣比較模糊,有少許的偽影存在,但是正常結(jié)構(gòu)的顯示尚可以;4分,組織結(jié)構(gòu)邊緣有一些模糊不清,不過(guò)沒(méi)有偽影的存在,能夠清晰顯示結(jié)構(gòu)間的關(guān)系;5分,邊緣清晰,無(wú)偽影。由SPSS22.0統(tǒng)計(jì)學(xué)軟件進(jìn)行處理,描述性數(shù)據(jù)先進(jìn)行相關(guān)性分析,體表輻射劑量分別進(jìn)行配對(duì)t檢驗(yàn)。圖像主觀質(zhì)量的評(píng)價(jià)分為一般清晰組和一般及差組,采用秩和檢驗(yàn)進(jìn)行統(tǒng)計(jì)學(xué)分析,檢驗(yàn)標(biāo)準(zhǔn)設(shè)定為a=0.05。結(jié)果:統(tǒng)計(jì)學(xué)分析發(fā)現(xiàn)隨著kV的降低CT有效劑量(ED)值也在降低。120 kV為3.21±0.19 msv,100 kV為1.92±0.14 msv,80 kV為0.75±0.07 msv,60 kV為0.23±0.02 msv,各組之間統(tǒng)計(jì)學(xué)分析均有差異性(P=0.000);主觀圖像質(zhì)量評(píng)價(jià)60k V組與其它各組間有統(tǒng)計(jì)學(xué)差異(P=0.000),其余各組之間沒(méi)有統(tǒng)計(jì)學(xué)差異。80 kV-120 kV(P=0.612),80 kV-100 kV(P=0.609),100 kV-120 kV(P=0.997)(Table 6)。客觀圖像質(zhì)量評(píng)價(jià),4組數(shù)據(jù)隨著kV的降低,其SNR值也持續(xù)降低,統(tǒng)計(jì)學(xué)分析100 kV和120 kV之間沒(méi)有統(tǒng)計(jì)學(xué)差異(P=0.344),其余各組之間均有統(tǒng)計(jì)學(xué)差異(P=0.000)(Table 7)。(詳細(xì)數(shù)據(jù)及統(tǒng)計(jì)學(xué)分析見(jiàn)附表)。因此按照盡量使用輻射防護(hù)最優(yōu)化低劑量原則(ALARA,as low as reasonably achievable),80 kV是比較理想的,既能滿足診斷要求,又能盡量降低輻射劑量。結(jié)論:1圖像質(zhì)量隨著kV值的降低而降低。2輻射劑量隨著kV值得降低而減少。3 80kV以下圖像質(zhì)量無(wú)法滿足診斷要求。4按照盡量使用輻射防護(hù)最優(yōu)化低劑量原則(ALARA,as low as reasonably achievable),80 kV是比較理想的,既能滿足診斷要求,又能盡量降低輻射劑量,通過(guò)將降低千伏,自動(dòng)毫安秒等傳統(tǒng)方面與最新的迭代算法相結(jié)合,達(dá)到了在降低千伏的同時(shí),可以取得滿足診斷要求的圖像質(zhì)量的目的。證明了80k V下通過(guò)迭代算法與自動(dòng)毫安秒技術(shù)可以在極大的降低輻射劑量的同時(shí)取得滿足診斷要求的圖像質(zhì)量。
[Abstract]:Objective: The X-ray dose of the unit volume of the child in the imaging examination is much higher than that of the adult, and the children are more sensitive to the X-ray radiation than the adult, and the damage to the children is much higher than that of the adult. Therefore, reducing the X-ray dose of the child in the image examination is a very meaningful work, and the aim of the experiment is to reduce the radiation dose of the child as much as possible on the premise of satisfying the image quality diagnosis requirement, The study produces the minimum radiation dose and meets the scan conditions required for diagnosis. Method: This experiment was performed under double-source CT. The device uses the Siemens Definition Flash dual-source CT, and selects the Flash Spiral mode for chest scanning, and the CARE Dose4D technology is opened in the examination. The model of the body model is 76-414-4150, and the body model produced by the American FLUKE Forkker Co., Ltd., which is distributed by the Shanghai AIDS Source Trading Co., Ltd. The experimental results show that the tube current is set to the automatic mA second, the pitch is 5.0, the thickness of the layer is 5.0 mm, and the reconstruction image adopts the SAFIRE3 iterative technique. The body model is placed according to the standard position of the chest scanning, and the body model is scanned for 50 times under each condition, and the thickness of the body model is adjusted at a time to simulate the children with different body shapes. the scan result is transmitted to the workstation to be processed next. Image analysis: (1) Image reconstruction and objective evaluation criteria: image reconstruction with AW4. 6 workstation (GE HehhCare, USA). The method of signal-to-noise ratio is used to evaluate the image objectively. The specific operation method is that the body model simulates the center position of the heart as the region of interest, the area is 3.0mm2, and the SD value and the CT value of the region are measured and recorded. The image-to-noise ratio (SNR) is calculated as the CT value/ noise SD of the corresponding region of interest (ROI). (2) Subjective evaluation standard: The image quality is evaluated and scored according to the clinical experience by a high-year-time image doctor with two sub-high professional titles. the quality of the image is divided into 1-5 points from the difference to the excellent, the specific standard is: 1 point, the normal tissue structure is not clear, the edge is blurred, the structure relationship of the tissue can not be distinguished completely, The edge of the tissue structure is relatively vague, with a few false shadows, but the display of the normal structure can still be; 4 points, the edge of the tissue structure has some ambiguity, but there is no pseudo-shadow, and the relationship between the structures can be clearly displayed; 5 points, sharp edges and no artifacts. The statistical software of SPSS22. 0 is used for processing, and the descriptive data is analyzed first, and the body surface radiation dose is respectively matched with t-test. The evaluation of the subjective quality of the image is divided into the general and the general and the difference group, and the statistical analysis is carried out by the rank sum test, and the test standard is set to a = 0.05. Results: The statistical analysis found that the effective dose (ED) of CT was also reduced with the decrease of the effective dose (ED). 120 kV was 3.21-0.19mv, 100 kV was 1.92-0.14msv, 80 kV was 0.75kV, 07msv, 60kV was 0.23-0.02msv, and there was a difference between the groups (P = 0.000). There was no statistical difference between the 60k V group and the other groups (P = 0.000), and there was no statistical difference between the other groups. 80 kV-120 kV (P = 0. 612), 80 kV-100 kV (P = 0. 609), 100 kV-120 kV (P = 0. 997) (Table 6). There was no statistical difference between 100 kV and 120 kV (P = 0.344), and there was no statistical difference between the other groups (P = 0.000) (Table 7). (See attached table for detailed data and statistical analysis). Therefore, as far as possible, the low-dose principle of radiation protection (ALARA, as low as possible) and 80 kV is ideal, which can not only meet the diagnostic requirements, but also reduce the radiation dose as much as possible. Conclusion: 1 The image quality is reduced with the decrease of the kV value. The radiation dose is reduced with the decrease of the kV. The quality of the image below 3 80kV can not meet the diagnostic requirements. The method not only can meet the diagnosis requirement, but also can reduce the radiation dose as much as possible, and can achieve the aim of meeting the image quality required by the diagnosis at the same time of reducing the kilovoltage by combining the traditional aspects such as the reduction of the kilovoltage, the automatic milliampere second and the like with the latest iteration algorithm. It is proved that the image quality that can meet the diagnosis requirement can be obtained at the same time when the radiation dose is greatly reduced by the iterative algorithm and the automatic milliamp second technology under the 80k V.
【學(xué)位授予單位】：河北醫(yī)科大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：R816.92
本文編號(hào)：2347053
[Abstract]:Objective: The X-ray dose of the unit volume of the child in the imaging examination is much higher than that of the adult, and the children are more sensitive to the X-ray radiation than the adult, and the damage to the children is much higher than that of the adult. Therefore, reducing the X-ray dose of the child in the image examination is a very meaningful work, and the aim of the experiment is to reduce the radiation dose of the child as much as possible on the premise of satisfying the image quality diagnosis requirement, The study produces the minimum radiation dose and meets the scan conditions required for diagnosis. Method: This experiment was performed under double-source CT. The device uses the Siemens Definition Flash dual-source CT, and selects the Flash Spiral mode for chest scanning, and the CARE Dose4D technology is opened in the examination. The model of the body model is 76-414-4150, and the body model produced by the American FLUKE Forkker Co., Ltd., which is distributed by the Shanghai AIDS Source Trading Co., Ltd. The experimental results show that the tube current is set to the automatic mA second, the pitch is 5.0, the thickness of the layer is 5.0 mm, and the reconstruction image adopts the SAFIRE3 iterative technique. The body model is placed according to the standard position of the chest scanning, and the body model is scanned for 50 times under each condition, and the thickness of the body model is adjusted at a time to simulate the children with different body shapes. the scan result is transmitted to the workstation to be processed next. Image analysis: (1) Image reconstruction and objective evaluation criteria: image reconstruction with AW4. 6 workstation (GE HehhCare, USA). The method of signal-to-noise ratio is used to evaluate the image objectively. The specific operation method is that the body model simulates the center position of the heart as the region of interest, the area is 3.0mm2, and the SD value and the CT value of the region are measured and recorded. The image-to-noise ratio (SNR) is calculated as the CT value/ noise SD of the corresponding region of interest (ROI). (2) Subjective evaluation standard: The image quality is evaluated and scored according to the clinical experience by a high-year-time image doctor with two sub-high professional titles. the quality of the image is divided into 1-5 points from the difference to the excellent, the specific standard is: 1 point, the normal tissue structure is not clear, the edge is blurred, the structure relationship of the tissue can not be distinguished completely, The edge of the tissue structure is relatively vague, with a few false shadows, but the display of the normal structure can still be; 4 points, the edge of the tissue structure has some ambiguity, but there is no pseudo-shadow, and the relationship between the structures can be clearly displayed; 5 points, sharp edges and no artifacts. The statistical software of SPSS22. 0 is used for processing, and the descriptive data is analyzed first, and the body surface radiation dose is respectively matched with t-test. The evaluation of the subjective quality of the image is divided into the general and the general and the difference group, and the statistical analysis is carried out by the rank sum test, and the test standard is set to a = 0.05. Results: The statistical analysis found that the effective dose (ED) of CT was also reduced with the decrease of the effective dose (ED). 120 kV was 3.21-0.19mv, 100 kV was 1.92-0.14msv, 80 kV was 0.75kV, 07msv, 60kV was 0.23-0.02msv, and there was a difference between the groups (P = 0.000). There was no statistical difference between the 60k V group and the other groups (P = 0.000), and there was no statistical difference between the other groups. 80 kV-120 kV (P = 0. 612), 80 kV-100 kV (P = 0. 609), 100 kV-120 kV (P = 0. 997) (Table 6). There was no statistical difference between 100 kV and 120 kV (P = 0.344), and there was no statistical difference between the other groups (P = 0.000) (Table 7). (See attached table for detailed data and statistical analysis). Therefore, as far as possible, the low-dose principle of radiation protection (ALARA, as low as possible) and 80 kV is ideal, which can not only meet the diagnostic requirements, but also reduce the radiation dose as much as possible. Conclusion: 1 The image quality is reduced with the decrease of the kV value. The radiation dose is reduced with the decrease of the kV. The quality of the image below 3 80kV can not meet the diagnostic requirements. The method not only can meet the diagnosis requirement, but also can reduce the radiation dose as much as possible, and can achieve the aim of meeting the image quality required by the diagnosis at the same time of reducing the kilovoltage by combining the traditional aspects such as the reduction of the kilovoltage, the automatic milliampere second and the like with the latest iteration algorithm. It is proved that the image quality that can meet the diagnosis requirement can be obtained at the same time when the radiation dose is greatly reduced by the iterative algorithm and the automatic milliamp second technology under the 80k V.
【學(xué)位授予單位】：河北醫(yī)科大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：R816.92
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