Study on the stability of the calibration and normalization in PET and the influence of drifts on the accuracy of quantification

With regard to the quality control of quantification in positron emission tomography some characteristics were examined, to develop a simple method for frequent monitoring. The stability and uniformity of the detector count rate was checked by plotting the RMS deviation of the non normalized count rate and the standard deviation of the normalized count rate, each normalized to its value after the calibration or normalization respectively. Switching off a single detector did not impair the image quality, but the normalized image pixel counts were reduced by 2%-3% when a detector block was switched off. Thus in case of need, a weak detector can still be used to perform a scan. A reduced count rate capability at specific activities above 5 x 10(4) Bq/ml (approximately 1.5 x 10(5) corrected true system counts/s or approximately 1.5 x 10(4)/s for a plane) was found compared to the maximum usable activity of 8 x 10(4) Bq/ml obtained 1 year earlier, indicating a drift in the count loss corrections. A variation of the room temperature changes the temperature distribution inside the gantry by 5% per degree C and the drift of the sensitivity (normalized image pixel counts) is 2% per degree C.     

PET与MRI三维脑图像高精度配准

目的 在PC机上实现高精度的PET与MRI三维脑图像配准。方法 采用最大互信息法对6例患者PET和MRI三维脑图像进行刚体配准。使用归一化互信息作为相似性量度。在互信息计算过程中，使用Powell多参数优化法和Brent一维搜索算法。为加快配准速度，使用了多分辨金字塔方法。采用基于坐标的阈值选取方法对PET图像进行分割预处理，消除星状背景伪影。结果 配准误差平均值为2．6mm，误差中位数平均为2．7mm。结论 配准视觉效果良好，评估证明该算法可达亚体元级配准精度。     

不同处理方式对FDG PET图像质量的影响

目的：研究不同重建方式对全身18F－脱氧葡萄糖（FDG）PET图像质量的影响。方法：5例正常对照者和5例恶性肿瘤患者全身18F－FDG PET显像（皆同时进行发射和穿透扫描），所有受检者的原始资料分别采用多种重建方式（无衰减滤波法重建，衰减滤波法重建，衰减迭代法重建），同时分析不同衰减平滑方法（Nonquantitative 和Gaussian)对图像质量的影响。结果：无衰减校正影像存在身体中间组织衰减明显，组织结构显示不清，病变容易变形，伪影多，图像质量差，病灶定位较困难，不能定量计算标准取值（SUV）等缺点，衰减校正滤波法重建图像在显示组织结构，定位病变及定量计算方面较非常衰减法好，但图像质量仍较差，衰减校正迭代法重建图像质量好，组织结构显示清楚，伪影少，病灶无变形，定位及定量都较准确，明显优于衰减和非衰减校正滤波法，衰减平滑方法对滤波法影响大，用Nonquantitative法明显优于Gaussian法，衰减平滑方法对迭代法影响较小，Gaussian法比Nonquantitative法略好。结论：不同重建方式对18F－FDG PET图像质量影响很大，以衰减校正迭代法重建（衰减平滑方法为Gaussian)图像质量最好。     

PET/CT图像采集时间对图像质量和病灶检出率的影响

目的探讨在不影响图像质量和病灶检出率前提下缩短PET／CT图像采集时间的可行性。方法18例接受PET／CT检查的患者，在CT扫描后按1、2、3min／床位依次进行3次PET扫描，共得到54帧图像。患者按体重分为以下3组：（1）45～60kg（7例），（2）61～75kg（7例），（3）76～90k（4例）。由2位有经验的医师共同阅片确定每例患者病变的位置和数目，图像质量由2位医师独立判断。结果3min／床位PET／CT图像上共检出127个病灶，其中最小的病灶直径约为3mm，除1min／床位图像漏检3个病灶外，其他所有病灶均能被1min／床位、2min／床位的图像识别。（1）～（3）组患者在3min／床位采集图像上识别的病灶数分别为71、41、15个，第1组患者的所有病灶在3种不同采集时间图像上均能被识别，第2组患者1min／床位采集图像遗漏了3个病灶，而2min／床位图像识别出的病灶数与3min／床位图像相同。第3组患者的所有病灶在3种采集图像上也均能被识别。1、2min／床位的PET图像质量均较3min／床位图像差，1min／床位图像质量最差，主要表现为图像本底噪声高、对比度差。3组患者中，第3组患者图像质量最差。结论对体重低于60瞻患者，1～3min的采集时间，病变的检出率无明显差异；而对体重60k以上患者，建议选择2～3min／床位的采集时间，对病情较重或不合作患者，根据需要可考虑选择1min／床位的采集时间。     

The influence of soccer-specific fatigue on functional stability

ObjectiveTo quantify the influence of soccer-specific fatigue on functional stability.Participants and designTen male semi-professional soccer players completed a 90 min treadmill protocol replicating the activity profile of match-play with a passive 15 min half-time interval.Main outcome measuresAt 15 min intervals players completed a 30 s single-legged balance task on an unstable platform. Balance performance was quantified as a stability index and the mean deflection of the platform.ResultsThere was no significant (P>0.05) main effect for exercise duration in the stability index, suggesting that balance performance was maintained throughout the simulated match. However, the mean deflection of the platform was significantly (P<0.05) shifted toward anterior displacement during the last 15 min of each half.ConclusionA change in balance strategy was evident during the latter stages of match-play, which may increase injury risk. It is recommended that soccer players perform proprioception training in the rested and exercised state to further develop neuromuscular control.     

复方樟柳碱注射液的稳定性研究

目的：考察复方樟柳碱注射液的稳定性。方法：依据质量标准考察外观、色泽,ｐＨ值,分解产物,无菌检查,澄明度和含量。结果：本品在６０℃３ｄ,８０℃１ｄ和４０℃３个月分解产物不合格;室温考察２年,各项结果均符合规定。结论：本品对高温不稳定,需在３０℃以下贮存,贮存期为２年。     

DXA骨密度测量质量控制中的精密度和准确度研究

目的探讨在双能X线吸收法（DXA）骨密度测量过程中运用精密度和准确度试验进行质量控制．提高骨密度测量结果可信度的重要性和必要性。方法①短期精密度试验：分别对30例受试者及30只SD雄性大鼠不同区域重复测量骨密度．运用统计学方法计算测量部位的精密度和骨密度最小显著变化值。②准确度试验：每日对厂家提供的腰椎模型进行测量．将测量结果与真实值比较，计算仪器测量的准确度并得出校正系数．根据测量的平均值建立Shewhart图。结果①受试者不同部位的重复测量误差计算结果：L2-4椎体、左右侧股骨颈、左右侧转子间区、左右侧全髋关节、左右侧股骨预上区的短期精密度[以变异系数的均方根（RMS-CV）％表示]和骨密度最小显著变化值分别为0．7%～2．2％和0．018～0．048g／cm^2。SD大鼠全身测量短期精密度为0．9％。②DXA骨密度仪的平均准确度为-0．81％，校正系数为0．992。连续25d测量结果平均值为1．244g／cm^2，标准差为0．008。结论进行短期精密度和准确度试验有助于了解仪器工作状态和测量结果分析，可有效提高骨密度测量的可信度。     

The evaluation and calibration of fan-beam collimators

The aims of this study were (a) to determine the true focal length of a fan-beam collimator and (b) to calibrate image size (mm/pixel) for each collimator to permit inter-comparison of image data acquired on different gamma camera systems. A total of six fan-beam collimators on three dual-head gamma camera systems were evaluated using a set of four cobalt-57 point source markers. The markers were arranged in a line in the transverse plane with a known separation between them. Tomographic images were obtained at three radii of rotation. From reconstructed transaxial images the distance between markers was measured in pixels and used to determine pixel size in mm/pixel. The system value for the focal length of the collimator was modified by up to ±100 mm and transaxial images were again reconstructed. To standardize pixel size between systems, the apparent radius of rotation during a single-photon emission tomography (SPET) acquisition was modified by changes to the effective collimator thickness. SPET images of a 3D brain phantom were acquired on each system and reconstructed using both the original and the modified values of collimator focal length and thickness. Co-registration and subtraction of the reconstructed transaxial images was used to evaluate the effects of changes in collimator parameters. Pixel size in the reconstructed image was found to be a function of both the radius of rotation and the focal length. At the correct focal length, pixel size was essentially independent of the radius of rotation. For all six collimators, true focal length differed from the original focal length by up to 26 mm. These differences in focal length resulted in up to 6% variation in pixel size between systems. Pixel size between the three systems was standardized by altering the value for collimator thickness. Subtraction of the co-registered SPET images of the 3D brain phantom was significantly improved after optimization of collimator parameters, with a 35%–50% reduction in the standard deviation of residual counts in the subtraction images. In conclusion, we have described a simple method for measurement of the focal length of a fan-beam collimator. This is an important parameter on multidetector systems for optimum image quality and where accurate co-registration of SPET to SPET and SPET to MRI studies is required. Received 17 October and in revised form 12 December 1998     

18 F-FDG剂量对PET模型图像质量的影响

目的：探讨不同剂量^18F-脱氧葡萄糖（FDG）对PET重建图像质量的影响。方法：将圆柱形模型分别用296、148、74、37、18．5、9．25和4．625MBq的^18F-FDG水溶液灌注后，置探头视野内行PET常规采集，然后用临床常规条件重建图像，从重建图像中抽取同一层面进行定量分析：热区标准摄取值（SUV）测定，热区与冷区SUV比值（ratio),本底区标准差（s)测定，采集过程中真实计数与随机计数的比值（T／R）。结果：296MBq时，图像直观非常不均匀，T／R＝0．83，其他各项指标无规律。148MBq时，图像所见外周放射性分布比较强，中间比较弱，与未经透射衰减校正的图像相似，T／R＝1．64。74、37和18．5MBq时，均匀性、分辨率、对比度都较好，本底噪声低，各项定量指标都较适呈。9．25和4．625MBq时，本底噪声非常高，信息量低，严重影响分辨率与均匀性。结论：行^18F-FDG PET显像最佳给药剂量是按体重4．625－11．1MBq/kg。     

显示器性能对影像识读影响的实验研究

目的 用实验方法研究显示器（CRT）性能对影像识读的影响。方法 （1）用ST-86LA型光度计对2台显示器（CRT1、CRT2）的亮度特性、均匀特性、对比度特性进行测试与比较，并绘制其受试者特性曲线（ROC）。（2）对模拟病变信号进行摄影，获取18幅实验影像，请3位影像诊断医师分别在2台显示器上进行识读，累计识读结果，绘制ROC曲线并进行分析。结果 （1）CRT1、CRT2的最大亮度分别为102和128cd／m^2，可辨识的最大密度胶片影像为D=1．51和1．81；边缘处的亮度分别为中心亮度的93．14％和92．97％；大面积对比度分别为48．12、41．25，小面积对比度为10．96和15．09。整体性能，CRT2优于CRT1。（2）ROC曲线下面积（Az）：大信号纵隔部Az1=0．8564、Az2=0．8806，差异无统计学意义（X^2=0．2916，P〉0．05）；肺野Az1=0．7967、Az2=0．8478，差异无统计学意义（X^2=1．3495，P〉0．05）；小信号纵隔部Az1=0．7876、Az2=0．8338，差异无统计学意义（X^2=0．5516，P〉0．05）；肺野Az1=0．6964、Az2=0．7958，差异具有统计学意义（X^2=4．9947，P〈0．05）。结论 （1）显示器性能对大信号识读影响小、对小信号识读影响大。（2）高密度影像受显示器性能影响大、低密度影像受显示器性能影响小。（3）在识读载有小信号的高密度所成影像时，为保证影像识读质量，应配备高性能的显示器。     

Comparison of lumbopelvic and dynamic stability between dancers and non-dancers

ObjectiveTo compare lumbopelvic stability between dancers and non-dancers by assessing lumbopelvic motor control, abdominal muscles automatic-activation, lumbar range of motion and dynamic stability.DesignCross-sectional.SettingUniversity/superior-dance-conservatory.ParticipantsTwenty-two dancers and 22 non-dancers.Main outcome measurementsThe active straight leg raise test (ASLR) was used to test lumbopelvic motor control with pressure feedback (mmHg). Transversus, rectus anterior and internal oblique muscles thicknesses were measured at rest and ASLR. For dynamic stability, the modified Star Excursion Balance Test (mSEBT) was employed.ResultsSignificant differences were revealed in lumbopelvic motor control between groups (p < 0.001). Abdominal muscles automatic-activation showed no differences between the groups. There were significant differences in the mSEBT for most of the test's directions, with dancers performing better than the non-dancers (p < 0.05). For the dancers, there were positive associations between motor control and dynamic stability, and between abdominal muscle thickness and mSEBT. For non-dancers, the rectus anterior activation correlated with the mSEBT.ConclusionsThe dancers had better lumbopelvic motor control, dynamic stability and lumbar movements except in terms of extension, as compared with non-dancers. Therefore, this novel study could stimulate a new line of research to determine the influence of these outcomes on sports performance, prevention and injury rehabilitation.     

不同衰减校正方法及无衰减校正对PET显像结果的影响

目的 探讨CT衰减校正(CTAC)、137Cs衰减校正(CsAC)及无衰减校正(NOAC)对PET图像质量和标准摄取值(SUV)的影响.方法 对Jaszczak模型及30例患者行PET/CT显像,均分别重建CTAC、CsAC和NOAC图像.30例患者中显像未见异常者9例,肺癌7例,肝癌4例,胰腺癌3例,肠癌7例.目测比较模型显像在CTAC、CsAC和NOAC时图像分辨率、均匀性的差异,计算CrAC、CsAC时模型显像均匀区各层面感兴趣区(ROI)的最大和最小百分比非均匀性(Nut),比较在CTAC和CsAC时平均SUV的差异.在图像上对患者正常软组织和骨组织、18F-脱氧葡萄糖(FDG)高摄取病灶以及高密度残留钡剂区勾画ROI,比较各ROI CTAC和CsAC的平均SUV差异,以及CTAC、CsAC和NOAC的图像差异.采用SPSS 12.0软件,2组数据间比较行配对t检验.结果 目测比较模型显像的图像分辨率,在CTAC和CsAC时无明显差异,NOAC图像中心区域的分辨率明显下降;CTAC和CsAC图像均匀性明显优于NOAC.CTAC图像Nut为(23±2)%(最大)、(19±1)%(最小),均匀性优于CsAC[Nut为(29±3)%(最大)、(23±2)%(最小)],两者平均SUV差异无统计学意义(0.9±0.1和1.0±0.1;t=0.367,P=0.719).患者正常软组织及FDG高摄取病灶CTAC和CsAC时的平均SUV差异无统计学意义(0.71±0.20和0.75±0.23,t=-2.159,P=0.054;5.50±4.80和5.70±5.00,t=-2.032,P=0.0.54);在正常骨组织及高密度残留钡剂区中,CTAC的平均SUV明显高于CsAC(1.37±0.29和1.18±0.36,t=7.960,P=0.001;1.82±0.62和0.92±0.20,t=3.451,P=0.018).正常软组织、骨组织及FDG高摄取病灶的CTAC和CsAC图像差异不影响诊断效果.高密度残留钡剂区在CTAC图像上表现为FDG高摄取伪影,而CsAC及NOAC图像上为正常摄取.结论 CTAC和CsAC的图像分辨率无明显差异,CTAC的图像均匀性优于CsAC,两者图像质量均明显优于NOAC;CTAC对高密度物质的SUV可明显高估,且可出现FDG高摄取伪影.     

Discovery ST PET性能测试与NEMA标准的应用

目的通过对1台 Discovery ST PET 的验收,探讨2001年版美国国家电气制造商协会(NEMA)标准的实际应用。方法使用 NEMA 标准的测试模型和测试方法,对 PET 空间分辨率、散射系数(SF,%)、计数丢失、随机测试和灵敏度进行测试。结果空间分辨率[半高宽(FWHM),mm]横向为6.12/6.37[二维/三维(2D/3D)],轴向为5.18/5.44(2D/3D);SF 为19.71(2D)和44.36(3D);系统灵敏度(计数·s~(-1)·kBq~(-1)):模型置有效视野中心位置为2.17/10.26(2D/3D),模型偏移至有效视野中心半径10cm 处为2.23/10.57(2D/3D)。结论厂家必须提供配套的 NEMA 测试模型和测试软件。该 PET/CT 仪的 PET 部分所测试指标达到出厂要求。     

Local dynamic stability of the lifting kinematic chain

While a stable trunk and centre of mass (CoM) trajectory are required during lifting, it is unclear how stability is controlled. Thirty healthy participants (15M, 15F) performed repetitive, symmetric lifting at 10 cycles per minute for 3 min with a load-in-hands equivalent to 10% of their maximum back strength. Short- and long-term maximum finite-time Lyapunov exponents (λ_max-s and λ_max-l), describing responses to small (local) perturbations, estimated the local dynamic stability of the foot, shank, thigh, pelvis, lower back, and upper back segments. Instability (λ_max-s) significantly increased when moving up the kinematic chain (p < 0.001). Therefore, to maintain trunk equilibrium and accurately regulate CoM trajectory during lifting, stability of the distal (fixed) lower limb segments is prioritized. This is contrary to previous results observed during gait, indicating that trunk control via kinematic chain stability is accomplished differently for walking and lifting.     

显示器亮度对诊断质量的影响

目的　探讨显示器 (cathode raytube,CRT)亮度对诊断质量的影响。 方法　采用物理测量与临床识读 2种实验方案。 (1 )设置CRT分别在高亮度档和低亮度档 (空白亮度分别为 1 1 2cd/m2 和 82cd/m2 ) ;(2 )将 2 1张密度 (density ,D)为 0 2 7～ 2 71的实验X线照片用 (德 )DUOSCANT2 0 0 0XL型专业扫描仪数字化 ,用 (国产 )ST 86LA型光度计测取 2种情况下对应不同密度胶片的CRT亮度 (lightness,L) ,绘制L D关系曲线。(3)用面积 2mm× 2mm～ 4mm× 4mm厚 0 5mm的铝片和铁片模拟病变信号 ,分别置于 1 3例志愿者 (其中男 7例 ,女 6例 )的肺野 (总计放置 42枚 )和纵隔 (总计放置 2 3枚 )部位进行摄影 ,经扫描仪数字化后 ,请 3位影像诊断医师分别在 2档亮度的CRT上进行识读 ,并行统计学处理 (χ2 检验 ,P <0 0 5为差异有显著性意义 )。结果　 (1 )CRT亮度L随胶片密度D的增大而迅速衰减 ;(2 )在低亮度档 ,D≥ 1 0时L即不再跟随D变化 ;但在高亮度档 ,其范围扩展至D≥ 1 5。 (3)在高、低亮度 2种观察条件下 ,3位医师对纵隔部累计识读出的信号数分别为 62个和 56个 ,诊断结果差异无显著性意义 (χ2 =2 1 1 ,P >0 0 5) ;但对肺野部累计识读出的信号数则分别为 87个和 2 9个 ,诊断结果的差异有非常显著性意义 (     

18F-FDG PET/CT伪影和不常见生理性摄取分析

目的 探讨^18F-脱氧葡萄糖（FDG）PET/CT显像各种伪影的影像学表现及其产生的原理.方法 回顾性分析^18F-FDG PET/CT检查患者的图像,根据伪影产生的原因进行分类,同时对临床不常见的生理性摄取进行分析.结果 伪影分为自身因素和设备技术因素伪影,自身因素所致伪影中以呼吸运动伪影和高密度物质伪影最为常见;设备因素伪影中以截断伪影、注射点外漏和放射性污染最为常见.不常见的生理性摄取包括：子宫内膜摄取、乳腺摄取和脂肪摄取.结论 PET显像伪影影像学表现可分为“热区”或“冷区”.不常见的生理性摄取主要表现为“热区”.伪影产生原因中以CT应用于PET显像后物理学因素多见.不常见的生理性摄取与检查技术有关.     

Quantitative assessment of the influence of location, internal temperature, idle time, and normalization on the sensitivity of a mobile PET/CT scanner

The superiority of PET/CT and (18)F-FDG imaging in cancer assessment has created the need in rural community hospitals to acquire this technology. However, high cost and lack of patient volume have prohibited these institutions from attaining in-house scanners. By using mobile PET/CT scanners, small rural hospitals are able to deliver this valuable clinical tool to their patients. As mobile PET/CT scanners are shifted from one site to another, however, they are exposed to harsher and frequently varying ecologic conditions that can alter their performance. Because of the importance of the standardized uptake value in cancer evaluation and its linear relationship to the sensitivity of the scanner, we investigated conditions affecting the sensitivity of the mobile PET/CT scanner. METHODS: We used a (68)Ge cylindric phantom with 2 bed frames scanned for 3 min each to simulate a patient to assess quantitatively the influence of location, increase in scanner internal temperature, idle time, and normalization on the sensitivity of the mobile PET/CT scanner. The raw phantom data were acquired and reconstructed with the parameters used for oncology patients. The scanner sensitivity values (Bq/mL) were obtained from circular regions of interest drawn on the phantom images. These values were compared with the true phantom activity concentration after it was decay-corrected to the specific scanning day. RESULTS: The average sensitivity errors (mean +/- SD) of this mobile PET/CT scanner at sites 1-4 were 1.84% +/- 0.98%, 2.43% +/- 2.05%, 2.08% +/- 0.91%, and 4.34% +/- 1.93%, respectively. A 41.17% increase in the scanner internal temperature decreased its sensitivity by an average of 16.09% +/- 3.58%. After day 1 and day 2, its average sensitivity errors were 3.27% +/- 0.01% and 2.65% +/- 0.02%, respectively. Before and after normalization, the average sensitivity errors were 3.06% +/- 1.37% and 2.69% +/- 1.69%, respectively. CONCLUSION: Temperature and normalization affected the sensitivity of the scanner the most and should be monitored closely, with normalization performed as recommended by the manufacturer.     

CT胶片感光性能和影像质量控制的研究

作者通过对进口，国产５种性能各异的ＣＴ胶片，在多幅相机上采用不同亮度和对比度进行试验后，选择出合适的感光条件，使ＣＴ图像质量能达到诊断要求。同时提出，图像质量指标的控制范围。     

18F-FDG PET/CT延迟显像数据采集参数推算方法的探讨

目的探讨PET／CT延迟显像需采集的总计数、计数率和采集时间的推算方法。方法对39例体格检查者行^18F-脱氧葡萄糖（FDG）PET／CT全身显像，并将其全身图像分为8个区段，估算各区段总计数占全身总计数的百分比。对另25例患者分别进行早期和延迟显像，并求出其早期显像平均计数率、相应区段延迟显像每床位需采集的总计数（Cdc）、理论推算计数率，然后启动PET数据采集程序，记录延迟显像的实测计数率。分别以Cdc除以理论推算和实测计数率，获得延迟显像理论推算和实际需要的采集时间。结果早期与延迟显像对应区段理论推算的每床位总计数、计数率和采集时间与对应的实测值问差异无统计学意义（t值分别为-0．273、1．609和-1．692，P值分别为0．788、0．120和0．103）；3—4h后延迟显像采集时间较早期显像延长约2．2倍。结论该方法可避免延迟显像数据采集的随意性，提高早期与延迟显像图像质量和定量指标的可比性。     

观片灯亮度对数字影像照片诊断效能影响的实验研究

目的 了解不同亮度观片灯对数字影像照片诊断准确性的影响.方法 测量临床实际工作环境中用到的所有观片灯,然后选出3个作为研究观片灯,分别代表高、中、低亮度,计算平均亮度值.应用Kodak DR 3000,曝光参数为75 kV、3.2 mAs,焦片距100 cm,对统计学摄影体模(TRG)进行摄影,获得体模影像照片.将该照片分别置于上述3种不同亮度的观片灯上,由3名医学影像科医师进行视读,用5值判断法获得信号和噪声的记分,计算出TRG模体中骨替代物和肌肉替代物的真阳性概率[P(S/s)]和假阳性概率[P(S/n)]值,绘制BOC曲线,并计算其准确性的判断概率值(Pdet).采用配对t检验比较对不同亮度的观片灯的Pdet值.结果3种观片灯的平均亮度值分别为(3489±256)、(2231±220)、(816±168)cd/m2.当骨替代物直径分别为0.6、0.7、0.8 mm,在高亮度观片灯上得到的Pdet值分别为0.558±0.009、0.788±0.008及0.813±0.006;中等亮度的观片灯的Pdet值分别为0.525±0.013、0.713±0.013及0.775±0.016;在低亮度观片灯上得到的Pdet值分别为0.475±0.022、0.550±0.018及0.688±0.020.肌肉替代物直径分别为0.9、1.0、1.2 mm时,在高亮度观片灯上,Pdet值分别为0.663±0.010、0.750±0.008及0.933±0.005;中等亮度观片灯上,得到的Pdet值分别为0.613±0.019、0.650±0.013及0.850±0.019;低亮度观片灯上,得到的Pdet分别为0.550±0.025、0.575±0.021及0.725±0.016,高亮度组与中亮度组、中亮度组与低亮度组之间分别进行配对t检验,差异均有统计学意义(t值分别为5.057和4.681,P<0.05).结论观片灯的亮度可影响诊断的准确性,观片灯的亮度越高,观察到的影像信息越丰富,诊断的准确性越高.