肺部低剂量CT体检中的价值探讨

目的探讨体检中肺部低剂量CT应用价值,为临床检查辐射剂量选择提供参考。方法对228例患者采用随机抽样方法分为常规剂量组(114例)和低剂量组(114例),分别采用肺部常规剂量CT扫描(扫描参数:130kV,50mAs,层厚6mm)和肺部低剂量CT扫描(扫描参数:130kV,15mAs,层厚6mm),对两组患者图像质量和扫描辐射量进行比较。结果两组CT扫描图像质量无明显区别;低剂量组CTDIvol1.64m,DLP及辐射剂量均显著优于常规剂量组,差异有统计学意义(P<0.05)。结论肺部低剂量CT用于体检可在减少辐射剂量的同时保证图像质量,具有一定临床价值。     

新生儿颅脑低剂量CT扫描参数研究

目的探讨新生儿颅脑低剂量CT扫描的最佳参数,降低扫描辐射剂量。方法选取颅脑CT检查的新生儿150例,随机等分成5组。扫描参数:管电压120kV,层厚、层间距6mm,管电流分别使用250、200、150、100、50mAs行全颅脑CT扫描,统一于左基底节层面测量各组CT值及标准差(SD)。对5组剂量扫描的CT剂量加权指数(CTDIw)、全头颅扫描剂量长度乘积(DLP)、噪声及图像质量对比分析。结果(1)随着扫描剂量的降低,CTDIw(mGy)及DLP值明显下降,50mAs组仅为常规剂量组的20%;(2)50mAs组扫描图像质量等级以较好和一般为主,100mAs及以上各组以好、较好为主,mAs降低,图像质量也下降;(3)50mAs组图像噪声较大,但颅内正常结构及病变组织显示尚清,且可通过调整窗宽和窗位,使图像质量得到提高,基本不影响诊断。结论50mAs低剂量新生儿颅脑扫描的图像质量有所下降,但不影响诊断,且由于辐射剂量显著降低,有效地保护了新生儿。     

眼眶部低剂量螺旋CT扫描参数的优化

目的:探讨眼眶部低剂量螺旋CT扫描参数的优化。方法:320例被检者分成16组(每组20例),将管电流140、110、80、60mA,层厚2和3mm,螺距0.75和1.5,设计成16组螺旋CT扫描参数。记录每组容积CT剂量指数(CTD-Iovl)和剂量长度乘积(DLP)平均值,分析管电流、层厚、螺距与辐射量的关系。图像质量从影像层次、背景噪声、解剖结构及能否满足诊断要求等方面进行综合评价,图像质量等级采用秩和检验分析。结果:X线辐射量与管电流呈正相关,当管电流从140mA降至80mA时,CTDIovl和DLP分别下降42.84%、42.86%,图像质量均符合诊断要求,且差异无统计学意义(P>0.05);降至60mA时,图像质量差异有统计学意义(P<0.05)。X线辐射量与螺距呈负相关,当螺距从0.75增至1.5时,CTDIovl和DLP分别下降49.98%、47.37%,图像质量差异无统计学意义(P>0.05)。X线辐射量与层厚关系不大,当层厚由3mm降至2mm时,CTDIovl和DLP分别降低9.90%、12.23%;图像质量差异无统计学意义(P>0.05),但2mm层厚的图像噪声较3mm大。结论:降低管电流,加大螺距是降低辐射量的有效途径;眼眶部螺旋CT扫描参数设置为管电流80mA、螺距1.5时,能兼顾图像质量和辐射量,扫描层厚根据检查要求选择。     

肺部低剂量螺旋CT放射剂量的研究

目的 :评价低剂量与常规剂量螺旋CT扫描的X线放射剂量比。方法 :对肺内结节用 2 0 0mAs行常规剂量螺旋CT扫描 ,扫描参数为 :12 0kV ,层厚 10mm ,扫描间隔 10mm ,螺距 1 5。选取不同层厚 (5mm、10mm)分别用 2 0 0mA、4 0mA、30mA、2 0mA、10mA扫描 ,记录各组每次扫描的单次CT剂量加权指数CTDIw(mGy)及mAs。对所有数据进行统计学处理 ,P <0 0 5时差异有统计学意义。结果 :2 0 0mA常规剂量组之CTDIW及毫安秒值与低剂量各组 (40mA、30mA、2 0、10mA)值比较差异有统计学意义 (P <0 0 5 ) ;以 2 0 0mAs常规剂量为标准 ,其余低剂量组 4 0mA ,30mA ,2 0mA ,10mA毫安秒及CTDIw分别降低了 80 %、90 %、95 %。结论 :用 2 0mAs低剂量螺旋CT扫描毫安秒及CTDIW仅仅相当于用 2 0 0mAs的 1/10 ,辐射剂量降低了 90 %。 2 0mA是肺部扫描的最佳剂量 ,具有辐射量小、敏感性强、性价比高的特点 ,值得推广应用。     

64层螺旋CT低剂量扫描在眶区外伤中的应用

目的探讨64层螺旋CT低剂量扫描在眶区外伤中的应用价值。方法收集180例眶区外伤患者,随机分为两组,A组90位患者行眶区常规剂量(115mAs)扫描,B组90位患者在其他参数不变的情况下,行低剂量(40mAs)扫描,比较常规剂量扫描与低剂量扫描的辐射剂量及图像质量。结果低剂量(40mAs)的辐射剂量明显低于常规剂量,低剂量组与常规剂量组间的CTDIvol、DLP值比较均有明显统计学意义(P<0.01)。结论眶区外伤低剂量扫描不仅有效降低辐射剂量,而且图像质量满足诊断需求。     

低剂量多层螺旋CT在头部应用的研究

目的：头颅CT扫描是诊断颅脑疾病最简单而有效的方法，越来越广泛地应用于临床。因而可能使被检者接受大量的X线辐射。本文探讨低剂量在头颅扫描中的应用，比较低毫安秒扫描和常规剂量扫描的图像质量。方法：选择20名60岁以上拟行头颅CT平扫的志愿者，进行多排螺旋CT常规剂量扫描：120KV，250mA，扫描架旋转速度1秒/周（剂量相当250mAs），螺距0．531：1，床速10．62mm/rot。扫描野250mm，扫描层厚5mm。然后改用低剂量扫描序列（即毫安降为125mA），在其它参数不变的情况下，于相同范围内行低剂量扫描。由3名CT医师按自定的标准双盲法评价每幅图像，图像质量分三级。其次，在脑灰质和脑白质区内以1-4mm兴趣区分别测量CT值和标准偏差。通过统计学方法分析和计算脑灰质显示率和对比度噪声比（CNR）。结果：低剂量组图像质量符合临床诊断要求的头颅图像占97．6％，低剂量图像与相应的常规剂量图像作）（2检验，p〉0．05，图像质量无明显差异。250mAs扫描组和低剂量组125mAs扫描组平均脑灰质显示率无明显差异（0．38vs0．41，p〉0．05）；250mAs扫描组平均CNR约高21％。所有125mAz扫描组的图像噪声比250mAs扫描组稍增加，但不影响诊断。结论：125mAs低剂量扫描可应用于脑血管意外及术后头颅凹扫描检查中。虽然图像噪声有所增加，但图像质量无明显下降。被检者放射辐射剂量却成倍减少。此法在颅脑疾病CT扫描检查中（如脑肿瘤、脑积水、脑血管意外及外伤等）值得推广应用。     

CT引导肺部穿刺活检的低剂量参数优选及应用

目的:评价肺部不同扫描参数下的辐射剂量和图像质量,探讨低剂量扫描在CT引导下肺部穿刺活检中的应用价值。方法:①CT引导下肺部穿刺活检的患者30例(肺穿组),扫描参数为10 mA,120 kV,层厚5 mm,螺距1.5,床速15 mm/s;30例患者(对照组)行胸部常规智能自动毫安扫描,参数为30~175 mA,平均(82.0±13.5)mA,120 kV,层厚10 mm,螺距1.5,床速30 mm/s;②分别比较两种扫描参数下的CT权重剂量指数(CTDIw)和剂量长度乘积(DLP)、图像质量及总扫描帧数。结果:30例肺穿患者在10 mA低剂量扫描参数下全部穿刺成功。肺穿组的CTDIw和DLP分别为(15.9±8.4)mGy和(2.9±2.3)Gy.cm,明显低于对照组(P<0.01)。结论:采用10 mA低剂量扫描参数,不仅可以保证CT引导下肺部穿刺活检成功,而且能减少患者的受线量。     

16层螺旋CT低剂量扫描在咽部检查的临床应用

目的：探讨16层螺旋CT低剂量扫描在咽部检查的临床应用价值，方法：使用GE Light Speed 16层螺旋CT，用120KV 50mA 10mm层厚扫描，扫完用2．5mm层厚重建。结果：35例中良好片占74．3%，一般片占23％，差片占2．70%。结论：该扫描方法延长球管寿命，降低病人单次检查接受的辐射剂量，值得推广。     

螺旋CT头颅扫描剂量的合理调整及其防护价值

目的：探讨能充分满足临床诊断需要且符合图像质量标准的CT扫描参数值,降低扫描辐射剂量。方法：①使用260、200、150、100、80mAs 5种剂量对模拟成人头颅的水模进行扫描,对获得的每幅图像选取相同的5个感兴趣区（ROI）测定并记录CT值的标准差,采用ROICT值标准差（SD）评价图像噪声。对各剂量组CT值标准差的均数和标准差作统计学处理;②随机选取来科全颅脑扫描显示颅内病变的10例,常规剂量260mAs扫描后,经患者同意,对病灶中心层面用200mAs加扫一层,对获取的两组图像质量进行盲式评判,评判标准依据空间分辨率、噪声及伪影将图像分为差、一般、较好、好四级。结果：①水模扫描：随着扫描剂量的降低,CTDIw（mGy）值明显下降,200mAs组比260mAs组降低13．34mGy;②图像噪声随着扫描剂量的降低而增加,但常规剂量260mAs组与减低剂量200mAs组间不存在差异（P〉0．05）;③260mAs和200mAs两种剂量的图像质量统计学处理无差异（Х^2=0．313,P=0．576）。结论：200mAs扫描剂量图像质量不受剂量降低而影响,但能降低辐射剂量,是可以实施调整的扫描参数,具有积极的放射防护意义。     

低剂量CT在颅脑-颌面部外伤联合扫描中的应用

目的前瞻性探讨16排螺旋CT颅脑-颌面部联合扫描,不同扫描参数在外伤中的应用效果并降低辐射剂量。资料与方法60例颅脑-颌面部外伤患者随机分为A、B、C3组(20例/组),在不同扫描参数下行多排螺旋(MSCT)检查。A组:扫描层厚10mm,重建层厚1.25mm和5mm;B组:扫描层厚5mm,重建层厚0.625mm;A、B两组均采用轴位扫描、16通道、2i、200mAs;C组:对照组(常规颅脑+颌面部扫描);A、B、C3组其他扫描参数相同。分别记录扫描时间(T)、CT剂量指数(CTDIvol)、Z轴范围(L)、剂量长度乘积(DLP)。由2位有经验的CT技师采取双盲法从图像噪声(IN)、对比-噪声比(CNR)两方面分析轴位、重建图像及多平面重组(MPR)、容积再现(VR)图像质量两两比较。结果A、B、C3组扫描时间(T)分别为12s、22.8s、18.53s,有效剂量(ED)分别为2.05mSv、2.19mSv、2.61mSv;A/C、B/C、A/B的CTDIvol值分别是48.34%、54.40%、88.85%;A/C、B/C、A/B每两组之间的DLP值两两比较差异均具有统计学意义(P值均<0.01),A、B、C...     

CT管电压对鼻窦图像质量和辐射剂量的影响研究

目的探讨CT管电压在鼻窦扫描中对图像质量和辐射剂量的影响。方法利用离体头颅标本,在逐层扫描方式下,分别选择5种不同的管电压(70、80、100、120、140 kV),对鼻窦区域进行扫描。噪声指数(NI)厂家默认为9,自动管电流调制,Smart mA设置为对应管电压下的最大范围。探测器宽度为120 mm。进行骨算法和软组织算法重建,层厚均为0.625 mm。按照临床实践的基线重组横断面、冠状面和矢状面图像,层厚2 mm。在横断面的中心层面上,选择相应的兴趣区测量CT值均值和标准差,计算对比度噪声比(CNR)。同时记录CT容积剂量指数(CTDIvol)和剂量长度乘积(DLP),并计算图像品质因子(FOM)。两名放射诊断医师和1名主管技师采用双盲法对实验所得图像进行主观评价,5分制标准计分。结果实验所得影像质量均满足诊断要求。在骨算法重建下,管电压为100和80 kV的CNR分别为66.98、64.75,高于管电压为70、120、140 kV的CNR值(51.61、61.56、57.76)。CTDIvol最大值为34.11 mGy(140 kV),最小值为17.45 mGy(70 kV)。管电压100 kV时的FOM值为152.26。在软组织算法重建下,管电压为80 kV的CNR为195.62,显著高于管电压为70、100、120、140 kV组(139.46、154.49、148.06、155.58)。管电压80 kV时的FOM值为1273.56,显著高于管电压为70、100、120、140 kV组(1114.56、809.98、735.63、709.62)。结论CT头颅标本鼻窦逐层扫描中,临床怀疑骨质病变时,优先选择骨算法100 kV;临床怀疑软组织病变时,优先选择软组织算法80 kV时,所得的图像质量最佳且受检者辐射剂量较低。     

Measurement of radiation dose in cerebral CT perfusion study

PURPOSE: To evaluate radiation dose in cerebral perfusion studies with a multi-detector row CT (MDCT) scanner on various voltage and current settings by using a human head phantom. MATERIALS AND METHODS: Following the CT perfusion study protocol, continuous cine scans (1 sec/rotation x60 sec) consisting of four 5-mm-thick contiguous slices were performed three times at variable tube voltages of 80 kV, 100 kV, 120 kV, and 140 kV with the same tube current setting of 200 mA and on variable current settings of 50 mA, 100 mA, 150 mA, and 200 mA with the same tube voltage of 80 kV. Radiation doses were measured using a total of 41 theroluminescent dosimeters (TLDs) placed in the human head phantom. Thirty-six TLDs were inside and three were on the surface of the slice of the X-ray beam center, and two were placed on the surface 3 cm caudal assuming the lens position. RESULTS: Average radiation doses of surface, inside, and lens increased in proportion to the increases of tube voltage and tube current. The lowest inside dose was 87.6+/-15.3 mGy, and the lowest surface dose was 162.5+/-6.7 mGy at settings of 80 kV and 50 mA. The highest inside dose was 1,591.5+/-179.7 mGy, and the highest surface dose was 2,264.6+/-123.7 mGy at 140 kV-200 mA. At 80 kV-50 mA, the average radiation dose of lens was the lowest at 5.5+/-0.0 mGy. At 140 kV-200 mA the radiation dose of lens was the highest at 127.2+/-0.6 mGy. CONCLUSION: In cerebral CT perfusion study, radiation dose can vary considerably. Awareness of the patient's radiation dose is recommended.     

Optimization of scanning parameters for multi-slice CT colonography: experiments with synthetic and animal phantoms

AIM: To determine the optimal collimation, pitch, tube current and reconstruction interval for multi-slice computed tomography (CT) colonography with regard to attaining satisfactory image quality while minimizing patient radiation dose. MATERIALS AND METHODS: Multi-slice CT was performed on plastic, excised pig colon and whole pig phantoms to determine optimal settings. Performance was judged by detection of simulated polyps and statistical measures of the image parameters. Fat and muscle conspicuity was measured from images of dual tube-current prone/supine patient data to derive a measure of tube current effects on tissue contrast. RESULTS: A collimation of 4 x 2.5 mm was sufficient for detection of polyps 4 mm and larger, provided that a reconstruction interval of 1.25 mm was used. A pitch of 1.5 allowed faster scanning and reduced radiation dose without resulting in a loss of important information, i.e. detection of small polyps, when compared with a pitch of 0.75. Tube current and proportional radiation dose could be lowered substantially without deleterious effects on the detection of the air-mucosal interface, however, increased image noise substantially reduced conspicuity of different tissues. CONCLUSION: An optimal image acquisition set-up of 4 x 2.5 mm collimation, reconstruction interval of 1.25 mm, pitch of 1.5 and dual prone/supine scan of 40/100 mA tube current is proposed for our institution for scanning symptomatic patients. Indications are that where CT colonography is used for colonic polyp screening in non-symptomatic patients, a 40 mA tube current could prove satisfactory for both scans.     

胸部CT低剂量扫描的图像质量与吸收剂量关系分析

目的　探索多层螺旋CT在胸部低剂量扫描的可能性和合理性。方法　 (1)X线吸收剂量测试 :用 12 0kV、0 75s、分别测试 8与 3mm层厚的 115 0、4 0 0、2 5 0、7 5mAsX线照射剂量。计算吸收剂量指数 ,并加以比较。 (2 )水体模测试CT值的均匀性和噪声水平 :在水体模的同一层面 ,用 12 0kV、 0 75s分别作 8与 3mm层厚的 115 0、4 0 0、2 5 0、7 5mAs扫描。在每幅图像的相同位置测 5个兴趣区 ,作CT值的均匀性和噪声水平比较。 (3)病例CT扫描 :随机选择肺部块影和片状影的患者各 30例。用 12 0kV ,0 75s,8与 3mm层厚在同一层面作 115 0、4 0 0、2 5 0、15 0、7 5mAs扫描。另选 15例作 190、15 0、4 0、2 5、15mAs螺旋扫描。作不同厚度的重建间隔对比和后处理图像最大密度投影 (MIP)、计算机容积摄影 (CVR)、多平面重建 (MPR)、高分辨率CT(HRCT)、三维成像(3D)、仿真支气管镜等效果比较。 (4)图像质量评估 :由 4名CT医生盲法评价CT图像。按正常图像、图像有少许伪影、图像有严重伪影的等级评判每一幅图像 ,进行统计学处理。结果　 (1)X线吸收剂量指数测试表明 ,115 0mAs的X线吸收剂量指数大于 4 0 0、2 5 0、7 5mAs的指数分别在 6 0 %、70 %、85 %以上。 (2 )水模测试结果 ,CT图像的均匀性随CT扫     

器官剂量调制技术对鼻窦CT图像质量和辐射剂量的影响

目的:探讨器官剂量调制(ODM)技术行鼻窦CT扫描时对图像质量和眼晶状体辐射剂量的影响。方法:应用GERevolutionevoCT对头部拟人模体进行扫描,不开启ODM为对照组,开启ODM为观察组。通过调整管电压(140、120、100 kV)、噪声指数(N17、N18)、螺距(准直宽度20 cm时0.531、0.96...     

低管电流联合 SAFIRE 重建在颈部肿大淋巴结的双能量 CT 扫描中的应用

目的：探讨低管电流联合 SAFIRE 重建的双能量 CT 扫描在颈部肿大淋巴结诊断中的应用。方法经病理证实的50例颈部肿大淋巴结的患者,进行常规 CT 平扫及双能量动脉期扫描,将其随机分为2组,即实验组和对照组,每组25例。实验组管电压分别为100 kV 和 Sn140 kV,管电流分别为117 mAs 和109 mAs,图像重建采用 SAFIRE 迭代重建技术,值选3;对照组管电压分别为100 kV 和 Sn140 kV,管电流分别为189 mAs 和165 mAs,1.0 cm,图像重建算法采用滤波反投影(FBP)技术,其余参数均相同。由2名有经验的医师对2组图像质量进行双盲法评分,利用 Kappa 检验比较观察者间评分的一致性;采用独立样本 t 检验比较2组患者的图像质量及有效辐射剂量。结果2组患者平均 CT 值的比较无统计学差异(P >0.05);2组噪声及信噪比(SNR)的比较有统计学差异(t 分别为4.705、4.403,P 分别为0.0008、0.0007);2组对比噪声比(CNR)无统计学差异(P >0.05);2组图像主观评分一致性较好(Kappa=0.720)且无统计学差异(P >0.05);实验组容积 CT 剂量指数(CTDIvol)为(10.801±0.594)mGy,剂量长度乘积(DLP)为(270.317±5.439)mGy·cm,有效辐射剂量(ED)为(1.594±0.031)mSv,对照组 CTDIvol 为(18.870±0.356)mGy, DLP 为(464.560±1.577)mGy·cm,ED 为(2.741±0.009)mSv,实验组 ED 较对照组降低约41.8%,且2组差异均有统计学意义(P <0.05)。结论在颈部肿大淋巴结的双能量扫描中,低管电流联合 SAFIRE 迭代重建能够在保证图像质量的同时,降低受检者所接受的辐射剂量。     

Individually weight-adapted examination protocol in retrospectively ECG-gated MSCT of the heart

The standard protocol in multislice spiral CT (MSCT) angiography for coronary arteries with fixed tube current-time settings leads to an overexposure and thus to an unnecessary high radiation dose in patients with lower weight when compared to heavier patients. The purpose of this study was to estimate the effect of reducing the radiation dose by adapting the tube current-time settings individually. Fifty patients underwent retrospectively ECG-gated MSCT of the heart. In 25 patients (group A₁) a standard protocol with constant tube current-time settings was used (4×1-mm collimation, 120 kV, 400 mAs_eff). Subsequently, artificial image noise was added to the data of these patients simulating a directive for weight-adapted tube current-time settings (group A₂). In the other 25 patients (group B) an alternative protocol with individually weight-adapted tube current-time settings was applied. The data of all groups were evaluated by a regression analysis. The image quality was assessed objectively by measuring the CT attenuation in standardised regions of interest and subjectively by three radiologists using a five-point scoring system in a consensus reading. Applying the weight-adapted tube current-time settings the effective radiation dose was reduced by 17.9% for men and 26.3% for women. The standard protocol leads to an overexposure in light patients as seen in the plot of noise vs weight (slope 0.16±0.07 HU/kg). By applying the weight-adapted tube current-time settings a weight-independent, constant image noise is achieved (slope 0.04±0.1 HU/kg). Diagnostic image quality was preserved in all patients. Individually weight-adapted tube current-time settings allow for a substantial dose reduction when performing retrospectively ECG-gated MSCT angiography for coronary arteries without impairment of diagnostic image quality.     

Must radiation dose for CT of the maxilla and mandible be higher than that for conventional panoramic radiography?

We evaluated the feasibility of performing preoperative spiral CT of the maxilla and mandible with a radiation dose similar to that used for conventional panoramic radiography. The skin entrance doses of radiation used for spiral CT (collimation, 1 mm; pitch, 2; tube voltage, 80 kV; tube current, 40 mA) and for panoramic radiography (75 kV, 8 mA, 15 seconds) were measured in one patient by using thermoluminescent dosimeter chips. Results were 0.56 +/- 0.06 mGy for CT and 0.59 +/- 0.04 mGy for radiography. Image quality was adequate for preoperative implant planning. Spiral CT of the mandible and maxilla may therefore be feasible with a radiation dose of similar magnitude as that used for conventional panoramic radiography.     

Multi-detector row CT colonography: effect of collimation, pitch, and orientation on polyp detection in a human colectomy specimen

PURPOSE: To investigate the effects of orientation, collimation, pitch, and tube current setting on polyp detection at multi-detector row computed tomographic (CT) colonography and to determine the optimal combination of scanning parameters for screening. MATERIALS AND METHODS: A colectomy specimen containing 117 polyps of different sizes was insufflated and imaged with a multi-detector row CT scanner at various collimation (1.25 and 2.5 mm), pitch (3 and 6), and tube current (50, 100, and 150 mA) settings. Two-dimensional multiplanar reformatted images and three-dimensional endoluminal surface renderings from the 12 resultant data sets were examined by one observer for the presence and conspicuity of polyps. The results were analyzed with Poisson regression and logistic regression to determine the effects of scanning parameters and of specimen orientation on polyp detection. RESULTS: The percentage of polyps that were detected significantly increased when collimation (P =.008) and table feed (P =.03) were decreased. Increased tube current resulted in improved detection only of polyps with a diameter of less than 5 mm. Polyps of less than 5 mm were optimally depicted with a collimation of 1.25 mm, a pitch of 3, and a tube current setting of 150 mA; polyps with a diameter greater than 5 mm were adequately depicted with 1.25-mm collimation and with either pitch setting and any of the three tube current settings. Small polyps in the transverse segment (positioned at a 90 degrees angle to the z axis of scanning) were significantly less visible than those in parallel or oblique orientations (P <.001). The effective radiation dose, calculated with a Monte Carlo simulation, was 1.4-10.0 mSv. CONCLUSION: Detection of small polyps (<5 mm) with multi-detector row CT is highly dependent on collimation, pitch, and, to a lesser extent, tube current. Collimation of 1.25 mm, combined with pitch of 6 and tube current of 50 mA, provides for reliable detection of polyps 5 mm or larger while limiting the effective radiation dose. Polyps smaller than 5 mm, however, may be poorly depicted with use of these settings in the transverse colon.     

定位像扫描参数对胸部CT影像质量和辐射剂量影响的模体研究

目的:探讨胸部CT定位像扫描参数(X射线管投照角度和管电压)的选择对图像质量和辐射剂量的影响规律,为临床实践中成像参数的选择提供指导。方法:选择不同扫描参数对成人胸部拟人模体进行定位像采集,X射线管投照角度(0°、90°和180°)、管电压(70、80、100、120和140 kV)和管电流(25 mA)共15种组合。...