Volume 44 Issue 6
Aug.  2020
Article Contents

Citation:

Analysis for acceptance test results of quality control in medical digital radiography equipment

  • Objective To analyze the quality control acceptance test results of partial types of medical digital radiography equipment, evaluate their application quality and provide references for the subsequent detection. Methods According to the Specifications of the quality control testing of medical X-ray diagnostic equipment (WS 76-2017) and the Specifications of quality control testing in medical digital radiography (DR) systems (WS 521-2017), 17 types (19 sets in total) of newly installed medical digital radiography equipment in Tianjin and Inner Mongolia from January 2018 to June 2019 were selected as the research objects. General and special test items, such as the deviation of tube voltage indication, output repeatability, dark noise, limited spatial resolution and low contrast details, and so on, were tested. Finally, the test results were recorded and analyzed. Results In addition to dark noise, detector dose indication, limited spatial resolution, low contrast detail detection, automatic exposure control (AEC) sensitivity, and AEC tube voltage change consistency to establish the baseline value, the detection results of other medical digital radiography equipment met the requirements of WS 76-2017 and WS 521-2017. The deviations of 60 and 80 kV tube voltage indication ranged from −3.61% to 2.71%, whereas the deviations of 100, 117, 120 and 121 kV tube voltage indication ranged from −2.9 to 4.9 kV. Meanwhile, the repeatability of output ranged from 0.0290% to 1.4700%, and the useful harness half value layers corresponding to 80 and 81 kV were between 2.5 and 5.9 mmAl. The deviations of exposure time indication in the range of ≥100 ms and <100 ms were −5.19% to 2.40% and −7.15% to 2.80%, respectively. There were no residuals and artifacts found in the imaging. The baseline values established by dark noise detection ranged from 14.2 to 5262.0, whereas the baseline values established by the detector dose indication were between 188 and 60,280. The baseline values of AEC sensitivity and those of the AEC tube voltage change consistency ranged from 0.67 to 6.90 mAs and from 2.20 to 6.69 μGy, respectively. The measurement results of response uniformity were between 0.11% and 4.70%. The ranging error were −0.40%−1.45%. The consistency between AEC ionization chambers were −8.70%−5.15%. The results of the limit spatial resolution in the horizontal and vertical directions ranged from 2.2 to 3.7 lp/mm and 2.2 to 3.4 lp/mm, respectively. Finally, the determination coefficients of the fitting formulas of signal transmission characteristics were all greater than 0.98. Conclusions The quality control acceptance test results of the medical digital radiography equipment met the requirements of the WS 76-2017 and WS 521-2017 standards. Clear and complete test conditions and acceptance test results can provide reference for the subsequent tests.
  • 加载中
  • [1] 王剑杰, 王雪鹃, 蒲朝煜. 恶性淋巴瘤的多模态显像研究进展[J]. 国际放射医学核医学杂志, 2018, 42(4): 363−368. DOI: 10.3760/cma.j.issn.1673−4114.2018.04.014.Wang JJ, Wang XJ, Pu CY. The research progress of multimodal imaging in malignant lymphoma[J]. Int J Radiat Med Nucl Med, 2018, 42(4): 363−368. DOI: 10.3760/cma.j.issn.1673−4114.2018.04.014.
    [2] Nelson D. Quality assurance workbook for radiographers and radiological technologists[J]. Can J Med Radiat Technol, 2003, 34(2): 15. DOI: 10.1016/S0820−5930(09)60026−8.
    [3] 中华人民共和国国家卫生和计划生育委员会. WS 76-2017医用常规X射线诊断设备质量控制检测规范[S]. 北京: 中国标准出版社, 2017.National Health and Family Planning Commission of the People's Republic of China. WS 76-2017 Specification for testing of quality control in medical X-ray diagnostic equipment[S]. Beijing: Standards Press of China, 2017.
    [4] 中华人民共和国国家卫生和计划生育委员会. WS 521-2017医用数字X射线摄影(DR)系统质量控制检测规范[S]. 北京: 中国标准出版社, 2017.National Health and Family Planning Commission of the People's Republic of China. WS 521-2017 Specification for testing of quality control in medical digital radiography (DR) systems[S]. Beijing: Standards Press of China, 2017.
    [5] 陈进良, 凌阳, 王军, 等. DR成像系统非优质图像的原因分析与优化策略[J]. 实用放射学杂志, 2012, 28(3): 479. DOI: 10.3969/j.issn.1002−1671.2012.03.042.Chen JL, Ling Y, Wang J, et al. Cause analysis and optimization strategy of image quality for DR imaging system[J]. J Pract Radiol, 2012, 28(3): 479. DOI: 10.3969/j.issn.1002−1671.2012.03.042.
    [6] 中华人民共和国国家质量监督检验检疫总局. JJG 1078-2012医用数字摄影(CR、DR)系统X射线辐射源[S]. 北京: 中国质检出版社, 2012.General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China. JJG 1078-2012 X-ray Radiation Sources for Medical Computed Radiography System and Digital Radiography System[S]. Beijing: China Quality Inspection Press, 2012.
    [7] 国家药品监督管理局. YY/T 0741-2018数字化摄影X射线机专用技术条件[S]. 北京: 中国标准出版社, 2018.State Drug Administration. YY/T 0741-2018 Particular specifications for digital X-ray radiography system[S]. Beijing: Standards Press of China, 2018.
    [8] Institute of Physics and Engineering in Medicine. Recommended Standards for the Routine Performance Testing of Diagnostic X-ray Imaging Systems[R]. York: IPEM, 2005.
    [9] Institute of Physics and Engineering in Medicine. Measurement of the Performance Characteristics of Diagnostic X-Ray Systems: Digital Imaging Systems[R]. York: IPEM, 2010.
    [10] American Association of Physicists in Medicine. An Exposure Indicator for Digital Radiography[R]. College Park: AAPM, 2009.
    [11] 魏超, 高杰, 张文艺, 等. 2016年天津市部分区医用X射线摄影机质量控制状态检测结果与分析[J]. 国际放射医学核医学杂志, 2018, 42(3): 257−260. DOI: 10.3760/cma.j.issn.1673−4114.2018.03.011.Wei C, Gao J, Zhang WY, et al. Quality control status test and analysis of partial radiography unit in Tianjin[J]. Int J Radiat Med Nucl Med, 2018, 42(3): 257−260. DOI: 10.3760/cma.j.issn.1673−4114.2018.03.011.
    [12] 孙涛, 李大鹏, 韩善清. 床旁数字化X射线摄影的质量保证与质量控制[J]. 中国医学装备, 2016, 13(4): 25−28. DOI: 10.3969/J.ISSN.1672−8270.2016.04.009.Sun T, Li DP, Han SQ. Research on QA and QC in bedside digital X-ray radiography[J]. China Med Equip, 2016, 13(4): 25−28. DOI: 10.3969/J.ISSN.1672−8270.2016.04.009.
    [13] 石建华, 石建忠. 山西省部分医疗机构医用X射线诊断设备影像质量控制检测结果分析[J]. 中国辐射卫生, 2018, 27(3): 231−233. DOI: 10.13491/j.issn.1004−714x.2018.03.011.Shi JH, Shi JZ. Analysis of testing results of image quality control in medical X-ray diagnostic equipment of some medical institutions in Shanxi Province[J]. Chin J Radiol Health, 2018, 27(3): 231−233. DOI: 10.13491/j.issn.1004−714x.2018.03.011.
    [14] 鲁慧, 何畅, 张峰, 等. 数字X线摄影的质量控制[J]. 中国民康医学, 2016, 28(9): 95−97. DOI: 10.3969/j.issn.1672−0369.2016.09.044.Lu H, He C, Zhang F, et al. Quality control digital radiography[J]. Med J Chin People's Health, 2016, 28(9): 95−97. DOI: 10.3969/j.issn.1672−0369.2016.09.044.
    [15] 郭垚, 陈凤娇, 谭展, 等. 佛山市医疗机构DR系统质量控制和放射防护检测结果[J]. 职业与健康, 2019, 35(17): 2313−2316. DOI: 10.3969/j.cnki.zyyjk.2019.0616.Guo Y, Chen FJ, Tan Z, et al. Results of quality control and radiation protection test of DR machines in medical institutions of Foshan City[J]. Occup Health, 2019, 35(17): 2313−2316. DOI: 10.3969/j.cnki.zyyjk.2019.0616.
  • 加载中
通讯作者: 陈斌, bchen63@163.com
  • 1. 

    沈阳化工大学材料科学与工程学院 沈阳 110142

  1. 本站搜索
  2. 百度学术搜索
  3. 万方数据库搜索
  4. CNKI搜索

Tables(5)

Article Metrics

Article views(8170) PDF downloads(32) Cited by()

Related
Proportional views

Analysis for acceptance test results of quality control in medical digital radiography equipment

    Corresponding author: Quan Wu, wuquan@irm-cams.ac.cn
  • Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Center of Radiation Detection and Evaluation, Institute of Radiation Medicine, Chinese Academy of Medical Sciences, Tianjin 300192, China

Abstract:  Objective To analyze the quality control acceptance test results of partial types of medical digital radiography equipment, evaluate their application quality and provide references for the subsequent detection. Methods According to the Specifications of the quality control testing of medical X-ray diagnostic equipment (WS 76-2017) and the Specifications of quality control testing in medical digital radiography (DR) systems (WS 521-2017), 17 types (19 sets in total) of newly installed medical digital radiography equipment in Tianjin and Inner Mongolia from January 2018 to June 2019 were selected as the research objects. General and special test items, such as the deviation of tube voltage indication, output repeatability, dark noise, limited spatial resolution and low contrast details, and so on, were tested. Finally, the test results were recorded and analyzed. Results In addition to dark noise, detector dose indication, limited spatial resolution, low contrast detail detection, automatic exposure control (AEC) sensitivity, and AEC tube voltage change consistency to establish the baseline value, the detection results of other medical digital radiography equipment met the requirements of WS 76-2017 and WS 521-2017. The deviations of 60 and 80 kV tube voltage indication ranged from −3.61% to 2.71%, whereas the deviations of 100, 117, 120 and 121 kV tube voltage indication ranged from −2.9 to 4.9 kV. Meanwhile, the repeatability of output ranged from 0.0290% to 1.4700%, and the useful harness half value layers corresponding to 80 and 81 kV were between 2.5 and 5.9 mmAl. The deviations of exposure time indication in the range of ≥100 ms and <100 ms were −5.19% to 2.40% and −7.15% to 2.80%, respectively. There were no residuals and artifacts found in the imaging. The baseline values established by dark noise detection ranged from 14.2 to 5262.0, whereas the baseline values established by the detector dose indication were between 188 and 60,280. The baseline values of AEC sensitivity and those of the AEC tube voltage change consistency ranged from 0.67 to 6.90 mAs and from 2.20 to 6.69 μGy, respectively. The measurement results of response uniformity were between 0.11% and 4.70%. The ranging error were −0.40%−1.45%. The consistency between AEC ionization chambers were −8.70%−5.15%. The results of the limit spatial resolution in the horizontal and vertical directions ranged from 2.2 to 3.7 lp/mm and 2.2 to 3.4 lp/mm, respectively. Finally, the determination coefficients of the fitting formulas of signal transmission characteristics were all greater than 0.98. Conclusions The quality control acceptance test results of the medical digital radiography equipment met the requirements of the WS 76-2017 and WS 521-2017 standards. Clear and complete test conditions and acceptance test results can provide reference for the subsequent tests.

    HTML

  • 医学影像学技术在临床诊断、疗效判断及预后评价中发挥着重要作用[1]。医用数字X射线摄影(digital radiography,DR)机作为现代医学影像学检查必备的影像工具,有其独特的优势,在临床诊断中的应用越来越广泛,未来有取代计算机X射线摄影和屏片摄影的趋势。DR机的影像是放射医师和技师对患者或受检者临床诊断判断的客观依据,其质量的优劣直接影响诊疗判断结果[2]。为确保DR机的影像质量和保证临床诊断的准确性,国家发布了卫生行业标准《医用常规X射线诊断设备质量控制检测规范》(简称WS 76-2017)[3]和《医用数字X射线摄影(DR)系统质量控制检测规范》(简称WS 521-2017)[4],规范DR机的质量控制检测要求、项目和方法,为医疗机构、技术服务机构等开展质量控制检测提供科学依据。

    DR机在临床使用过程中已经规范化和程序化,设备易操作,所得图像直观易读,提高了放射工作人员的工作效率。但其图像质量受多种因素的影响,如曝光参数、拍摄体位、人为操作规范程度和设备性能优劣等[5]。鉴于此,我们依据标准的要求,对天津市和内蒙古自治区部分医疗机构新安装的17种型号的DR机进行验收检测,评价其应用质量状况,论证对应标准在实施过程中的实用性,为国家完善相关标准提供必要的参考;同时,分析通用检测项目和专用检测项目指标的验收检测结果可为相关机构后续DR机的状态检测和稳定性检测提供初始装机的基线值和检测条件,进而保证临床医师和技师使用DR机的安全性和有效性,以便后续更好地为患者和受检者服务。

1.   资料与方法

    1.1.   研究对象

  • 选取2018年1月至2019年6月天津市和内蒙古自治区部分医疗机构新安装的17种型号的DR机共19台(含8台双探测器、4台单探测器和7台移动式摄影机),对其开展质量控制验收检测。检测前,生产厂家的工程师提前完成对设备必要的校正与维护,确保设备性能达到最佳状态。具体DR机信息情况见表1

    序号型号生产厂家类型数量(台)探测器数量(个)额定参数[电压(kV)/电流(mA)]
    1 FUJIFILM DR CALNEO 日本FUJIFILM公司 固定机 3 2 150/630
    2 Discovery XR656 美国GE公司 固定机 1 2 150/800
    3 Definium 6000 北京通用电气华伦医疗设备有限公司 固定机 1 2 150/630
    4 Ysio Max 德国SIEMENS公司 固定机 1 2 150/1000
    5 VX 3733-SYS 美国Carestream Health公司 固定机 1 2 150/1000
    6 新东方1000MD 北京万东医疗科技股份有限公司 固定机 1 2 150/630
    7 Digital Diagnost Power 荷兰PHILIPS公司 固定机 1 1 150/1000
    8 SONTU100-RAD-Ⅱ 深圳市深图医学影像设备有限公司 固定机 1 1 125/500
    9 新东方1000MC 北京万东医疗科技股份有限公司 固定机 1 1 150/630
    10 H50-RA 北京万东医疗科技股份有限公司 固定机 1 1 150/500
    11 FDR GO f-g 日本FUJIFILM公司 移动机 1 1 130/400
    12 Optima XR220amx 美国GE公司 移动机 1 1 125/500
    13 MUX-100DJ 北京岛津医疗器械有限公司 移动机 1 1 125/400
    14 DRXR-1 美国Carestream Health公司 移动机 1 1 150/400
    15 HM-200 北京万东鼎立医疗设备有限公司 移动机 1 1 125/200
    16 MUX-200D 北京岛津医疗器械有限公司 移动机 1 1 133/400
    17 6000A 深圳蓝韵医学影像有限公司 移动机 1 1 150/400
    注:表中19台医用数字X射线摄影机是2018年1月至2019年6月安装的

    Table 1.  Basic information of 19 medical digital radiography equipments

  • 1.2.   检测仪器

  • 瑞典Unfors Raysafe公司的X2型X射线多功能检测仪(常规管电压测量量程为40~150 kV,测量半价层量程为1~14 mm Al,剂量率响应量程为1 nGy/s~500 mGy/s,测量时间为1 ms~999 s);德国IBA公司 DIGI-13型CR/DR-26检测板和4090R型屏/片密着检测板;德国PTW公司的GKQC型毫米级铅尺;北京普林康有限公司的PLK-QA型有用线束垂直度偏离测试筒及光射野一致性测试板、空间分辨力测试卡(0.6~5.0 lp/mm)、纯度不低于99.5%的亚毫米和毫米级厚度的铝片、1 mm厚的铜板(15 cm×15 cm)、2 mm厚的铅板(15 cm×15 cm)和4 mm厚的铅块(4 cm×4 cm)及卷尺等。凡是涉及需要检定或校准的计量器具均在中国计量科学研究院或天津市计量监督检测科学研究院进行刻度,且证书的日期在有效范围内。

  • 1.3.   检测项目

  • 依据WS 76-2017[3]、WS 521-2017[4]、《医用数字摄影(CR、DR)系统X射线辐射源》[6]、《数字化摄影X射线机专用技术条件》[7]和国外研究机构相关报告[8-10]的要求,对DR机通用检测项目和专用检测项目进行检测。具体检测指标和要求见表2

    序号检测项目主要的检测要求和条件判定标准
    1 管电压指示的偏离 大焦点和小焦点:60 、80 、100 、120 kV条件下分别曝光 ±5.0%或±5.0 kV内,以较大者控制
    2 输出量的重复性 80 kV、测量5次 ≤10.0%
    3 有用线束半值层 80 kV ≥2.3 mm Al
    4 曝光时间指示的偏离 80 kV、曝光时间≥100 ms ±10.0%内
    80 kV、曝光时间<100 ms ±2 ms内或±15.0%内
    5 有用线束垂直度偏离 球管垂直向下,SID=100 cm,测试板平放接收器上表面
    测试筒垂直于测试板中心
    ≤3°
    6 光野与照射野四边的偏离 任一边±1 cm内
    7 暗噪声 关闭遮线器、2 mm铅板、最低mA或mAs和kV曝光,记录像素 影像均匀无伪影
    8 DDI 1 mm铜板、SID=180 cm、70 kV和适当mAs(约10 µGy)下
    重复曝光3次
    DDI或平均像素值建立基线值
    9 信号传递特性 1 mm铜板、SID=180 cm、70 kV、适当mAs(约1、5、
    10、20、30 µGy)曝光
    R2≥0.98
    10 响应均匀性 选用测量DDI的图像 变异系数≤5.0%
    11 测距误差 SID=180 cm、50 kV,10 mAs曝光,测距软件对水平和
    垂直方位测量
    ±2.0%内
    12 残影 关闭遮线器、2 mm铅板和4 mm铅块,两种条件曝光3次 不存在残影或有残影而像素值
    误差≤5.0%
    13 伪影 SID=180 cm、60 kV、10 mAs,对屏/片密着检测板成像曝光 无伪影
    14 极限空间分辨力 SID=180 cm、厂家条件或60 kV、3 mAs,水平和垂直方位测量 ≥90.0%厂家规定值,或≥80.0%fNyquist,建立基线值
    15 低对比度细节 按模体说明书条件,选择1、5、10 µGy 3次曝光 建立基线值
    16 AEC灵敏度 1 mm铜板、70 kV、自动mAs曝光,记录mAs 建立基线值
    17 AEC电离室之间的一致性 1 mm铜板、70 kV、选择单个电离室有效、自动mAs曝光,
    记录mAs或DDI
    ±10.0%内
    18 AEC管电压变化的一致性 1 mm铜板、70 、80 、90 、100 kV,自动mAs曝光,
    记录剂量值或DDI值
    建立基线值
    注:表中,序号1~6为通用检测项目,7~18为专用检测项目(实际检测过程中记录是否有滤线栅)。DDI:探测器剂量指示;SID:影像探测器距离;AEC:自动曝光控制;fNyquist:尼奎斯特频率

    Table 2.  Test items and conditions of medical digital radiography equipments

  • 1.4.   质量控制

  • 现场检测人员实行持证上岗,双人检测、校核,确保数据客观、真实和有效;遵循中国医学科学院放射医学研究所的质量管理体系手册和程序文件,保证测量工作程序和方法的科学系统性;检测仪器在有效期范围内进行检定和校准。

2.   结果
  • 通过对新安装的17种型号共19台DR机进行验收检测,通用检测项目的部分检测结果见表3。由表3可见:在大焦点和小焦点下,60 kV和80 kV的管电压指示的偏离为−3.61%~2.71%,100 、117、120和121 kV的管电压指示的偏离为−2.9~4.9 kV;输出量重复性为0.0290%~1.4700%;80 kV和81 kV对应的有用线束半值层为2.5~5.9 mm Al,在设置时间≥100 ms和<100 ms时,曝光时间指示的偏离分别为−5.19%~2.40%和−7.15%~2.80%。另外,有用线束垂直度偏离均<3°,光野与照射野四边的偏离为−0.9~0.7 cm。

    型号检测条件[电压(kV)] 检测条件[电压(kV)/
    电流时间积(mAs)]
    检测条件[电压(kV)/
    曝光时间(s)]
    管电压指示的偏离
    (大焦点)
    管电压指示的偏离
    (小焦点)
    输出量
    重复性(%)
    有用线束
    半值层
    (mm Al)
    0.1 s曝光时间
    指示的偏离(%)
    0.8 s曝光时间
    指标的偏离(%)
    FUJIFILM DR CALNEO 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    1.00% −1.80% 0.81 kV 0.78 kV 0.96% 0.34% 2.1 kV 1.0 kV 0.0582 2.5 −0.30 −0.33
    FUJIFLLM DR CALNEO 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    −1.10% −0.55% 0.74 kV 4.1 kV −1.10% 0.27% 1.6 kV −0.50 kV 0.0643 2.9 −0.20 −0.33
    FUJIFLLM DR CALNEO 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    0.52% −1.90% −1.9 kV −2.1 kV 0.077% −1.20% −1.8 kV −2.4 kV 0.0700 3.2 −5.19 −6.50
    Discovery XR656 60 80 100 120 60 80 100 120 80/25 80/0.1 80/0.08
    −0.70% −0.70% 0.20% 0.6 kV −0.70% −0.70% 0.20% 0.9 kV 0.0800 3.4 0.03 0
    Definium 6000 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    −1.90% −2.30% −1.70% −0.81% −2.10% −2.50% −1.70% −0.55% 0.0400 3.1 0.03 −2.33
    Ysio Max 60 81 100 121 60 81 100 121 81/40 81/0.1 81/0.08
    −1.15% −1.22% 0.02 kV 0.37 kV −0.980% −1.31% −0.50 kV 0.57 kV 0.4900 3.1 −0.03 0.17
    VX 3733-SYS 60 80 100 120 60 80 100 120 80/50 80/0.1 80/0.04
    0.54% −0.62% 0.66 kV 3.15 kV 0.59% −0.78% 0.40 kV 3.10 kV 0.0358 5.9 −0.50 −1.17
    新东方1000MD 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    0.92 kV −0.40 kV −0.70 kV −0.64 % 0.75 kV −0.60 kV −0.98 kV −0.58 % 0.2500 3 1.80 1.90
    Digital Diagnost Power 60 81 102 117 60 81 102 117 81/40 81/0.1 81/0.08
    0.34% 1.10% 2.3 kV 2.8 kV 0.17% 1.50% 2.1 kV 1.8 kV 0.0800 4.9 −0.17 −0.17
    SONTU100-RAD-Ⅱ 60 80 100 120 60 80 100 120 80/25 80/0.1 80/0.08
    −1.53% −1.48% 0.17 kV 2.4 kV −1.74% −1.86% −0.26 kV 2.5 kV 1.1700 2.92 −4.93 −6.25
    新东方1000MC型 60 80 100 120 60 80 100 120 80/32 80/0.1 80/0.08
    2.50 % 0.98 % −1.08 % −1.6 kV 1.2 % 0.55 % −1.5 % −1.2 kV 0.0970 2.8 2.40 2.80
    H50-RA 60 80 100 120 60 80 100 120 80/25 80/0.1 80/0.08
    2.71% 2.40% 3.2 kV 3.7 kV 1.72% 1.73% 3.3 kV 4.9 kV 1.4700 3.6 1.97 2.30
    FDR GO f-g 60 80 100 120 80/20
    1.30% 2.50% 3.2 kV 4.4 kV 0.1070 3.3
    Optima XR220amx 60 80 100 120 60 80 100 120 80/16
    −0.60% 0.40% 2.60% 3.5 kV −0.70% 0.40% 2.70% 3.6 kV 0.0300 3.2
    MUX-100DJ 60 80 100 120 80/80
    −0.02 kV −0.45 kV −0.04 kV 0.37% 0.0290 3.1
    DRXR-1 60 80 100 120 60 80 100 120 80/4
    −2.60% −3.50% −2.5 kV −1.3 kV −2.60% −3.00% −2.3 kV −0.98 kV 0.0330 2.9
    HM-200 60 80 100 120 60 80 100 120 80/12.5 80/0.1 80/0.08
    −2.67% −3.32% −2.9 kV −1.8 kV −2.23% −3.61% −2.4 kV −2.1 kV 0.1000 2.8 −4.34 −7.15
    6000 A 60 80 100 120 60 80 100 120 80/20 80/0.1 80/0.08
    −1.00% −1.50% −1.6 kV −1.8 kV −0.94% −1.5% −1.9 kV −1.8 kV 0.1600 2.6 −1.50 −2.10
    MUX-200D 60 80 100 120 60 80 100 120 80/20
    1.30% 0.079% −0.42 kV −0.16 kV 0.35% 0.50% 0.11 kV 0.040 kV 0.0826 3.3
    注:表中,“—”表示受检设备无此项功能

    Table 3.  Partial test results of general items of 19 medical digital radiography equipments

    通过对这19台(27个探测器)DR机的专用检测项目进行检测,依据WS 521-2017[4]的要求,对暗噪声、探测器剂量指示、极限空间分辨力、低对比度细节、自动曝光控制(automatic exposure control,AEC)灵敏度和AEC管电压变化的一致性建立基线值,对其余检测指标进行合格与否的结果判定。成像中均不存在残影和伪影;暗噪声检测建立的基线值(像素值)为14.2~5262.0;探测器剂量指示建立的基线值(像素值)为188~60 280;AEC灵敏度的基线值为0.67~6.90 mAs;AEC管电压变化一致性的基线值为2.20~6.69 μGy。响应均匀性为0.11%~4.70%;测距误差为−0.40%~1.45%;AEC电离室之间一致性为−8.70%~5.15%。其余专项检测项目(如极限空间分辨力、低对比度细节和信号传递特性)的检测结果见表4。由表4可见,探测器在水平方向和垂直方向的极限空间分辨力分别为2.2~3.7 lp/mm和2.2~3.4 lp/mm;低对比度细节在不同的入射空气比释动能下,能够分辨1~7个细节变化;信号传递特性的拟合公式的决定系数均>0.98。

    型号(位置) 检测条件[电压(kV)/电流时间积(mAs)] 检测条件[空气比释动能(μGy)] 信号传递特性
    极限空间分辨力
    (水平,lp/mm)
    极限空间分辨力
    (垂直,lp/mm)
    低对比度细节a拟合公式决定
    系数
    FUJIFILM DR CALNEO 70/3.2 5.63 25.23 49.09 y=36.2201x+2639.0116 0.9853
     (诊断床) 2.8 2.8 4(2.0%) 6(1.2%) 7(0.8%)
    FUJIFILM DR CALNEO 70/3.2 5.63 25.23 49.09 y=26.7748x+2747.8897 0.9883
     (胸片架) 3.1 2.8 4(2.0%) 6(1.2%) 7(0.8%)
    FUJIFLLM DR CALNEO 60/3.2 5.56 24.74 49.16 y=0.4259x+3439.5103 0.9896
     (诊断床) 2.8 2.8 4(2.0%) 6(1.2%) 7(0.8%)
    FUJIFLLM DR CALNEO 60/3.2 5.87 24.87 49.22 y=0.2075x+3669.5999 0.9841
     (胸片架) 3.1 3.1 4(2.0%) 6(1.2%) 7(0.8%)
    FUJIFLLM DR CALNEO 70/10 6.07 13.21 50.85 y=2.3252x+3625.7 0.9966
     (诊断床) 3.1 3.1 1(5.6%) 2(4.0%) 6(1.2%)
    FUJIFLLM DR CALNEO 70/10 6.07 13.21 50.85 y=1.6705x+2335.8 0.9907
     (胸片架) 3.1 3.1 1(5.6%) 3(2.8%) 5(1.6%)
    Discovery XR656 60/3.2 10.05 50.11 100.60 y=292.62x−187.07 0.9923
     (诊断床) 2.2 2.2 3(2.8%) 7(0.8%) 7(0.8%)
    Discovery XR656 60/3.2 10.05 50.11 100.60 y=283.78x−177.69 0.9923
     (胸片架) 2.2 2.2 6(1.2%) 7(0.8%) 7(0.8%)
    Definium 6000 60/3 0.99 5.04 10.07 y=245.87x+6.0058 0.9998
     (诊断床) 2.5 2.5 5(1.6%) 6(1.2%) 7(0.8%)
    Definium 6000 60/3 0.99 5.04 10.07 y=223.42x−12.242 0.9999
     (胸片架) 2.5 2.5 5(1.6%) 6(1.2%) 6(1.2%)
    Ysio Max (诊断床) 69.8/0.6 6.23 10.48 y=−1.3946x2−37.484x+3023.9 0.9843
    3.1 3.1 2(4.0%) 3(2.8%)
    Ysio Max (胸片架) 69.8/0.6 5.85 11.31 y=3203.1e−0.242x 0.9928
    3.1 3.1 2(4.0%) 4(2.0%)
    VX 3733-SYS 100/1 0.93 4.84 10.33 y=31.3035x+1742.2107 0.9817
     (诊断床) 3.4 3.4 3(2.8%) 4(2.0%)
    VX 3733-SYS 100/1 0.93 4.84 10.33 y=33.9846x+1721.9055 0.9822
     (胸片架) 3.7 3.4 3(2.8%) 4(2.0%)
    新东方1000MD 60/3.2 11.96 62.33 123.6 y=73.386x−28.374 0.9992
     (诊断床) 3.1 3.1 3(2.8%) 4(2.0%) 5(1.6%)
    新东方1000MD 60/3.2 5.03 25.58 51.14 y=130.65x+90.574 0.9999
     (胸片架) 3.1 3.1 1(5.6%) 4(2.0%) 5(1.6%)
    Digital Diagnost Power 60/3.1 5.68 11.97 50.02 y=2598.5lnx+14366 0.9999
    3.4 3.4 4(2.0%) 5(1.6%) 5(1.6%)
    SONTU100-RAD-Ⅱ 70/1.6 10.23 47.49 92.95 y=23.81x−33.218 0.9813
    3.1 3.1 7(0.8%) 7(0.8%) 7(0.8%)
    新东方1000MC型 60/3.2 9.35 47.11 93.09 y=159.05x+136.50 0.9993
    2.6 2.2 2(4.0%) 6(1.2%) 7(0.8%)
    H50-RA 48/16 10.37 42.88 94.10 y=142.12x+96.56 0.9922
    3.4 3.4 3(2.8%) 5(1.6%) 6(1.2%)
    FDR GO f-g 60/3.2 5.53 28.50 45.64 y=0.6136x+3692.2431 0.9829
    3.1 3.1 3(2.8%) 4(2.0%) 5(1.6%)

    Table 4.  Test results of partial special test items of 19 medical digital radiography equipments

    续表4               4 19 台医用数字 X 射线摄影机部分专用项目的检测结果
    Table 4  Test results of partial special test items of 19 medical digital radiography equipments
    型号(位置) 检测条件[电压(kV)/电流时间积(mAs)] 检测条件[空气比释动能(μGy)] 信号传递特性
    极限空间分辨力
    (水平,lp/mm)
    极限空间分辨力
    (垂直,lp/mm)
    低对比度细节a拟合公式决定
    系数
    Optima XR220amx 60/3.2 11.30 45.88 92.88 y=354.11x+17.76 0.9895
    2.5 2.5 4(2.0%) 5(1.6%) 5(1.6%)
    MUX-100DJ 40/20 2.96 16.08 30.15 y=5958.2240x+18.9556 0.9999
    3.1 3.1 5.60% 3(2.8%) 4(2.0%)
    DRXR-1 100/1 1.09 4.95 9.66 y=31.9723x+1759.0326 0.9828
    3.4 3.4 2(4.0%) 4(2.0%)
    HM-200 60/3 13.96 48.29 96.78 y=1009.6lnx+ 302.98 0.9881
    2.5 2.5 2(4.0%) 4(2.0%) 6(1.2%)
    6000 A 60/3.2 14.20 79.20 162 y=137.86x+122.81 0.9996
    3.1 3.1 1(5.6 %) 4(2.0%) 5(1.6%)
    MUX-200D 60/2 5.04 10.25 20.86 y=1.9844x+86.126 0.992
    3.1 3.1 2(4.0%) 3(2.8%) 3(2.8%)
    注:表中,a:低对比度细节的表述方式为“细节数(对比度)”,细节数为检测时可看到细节个数,对比度为检测时可看到最低对比度;“—”表示无法满足检测条件
3.   讨论
  • 数字X射线摄影检查技术优化了临床拍片工作流程,提高了工作效率。随着DR机的使用和损耗,其性能的可靠性将影响图像质量,进而可能无法准确反映异常组织。相关研究结果表明,医疗机构加强对DR机的质量控制是保障高质量影像信息的有效措施[11-12]。定期对DR机进行质量控制和检测,可及时发现异常情况并及时修复,进而保障广大患者和受检者的生命质量[13-14]。有研究结果表明,DR机的质量控制检测合格率为53.3%[15],这就更加说明后续对DR机开展质量控制检测和定期维护保养的重要性。同时,检测机构也应加强对标准的理解和提高开展质量控制检测方法的应用能力。

    在本研究中,我们对17种型号的DR机进行质量控制验收检测,结果发现,通用检测项目的检测结果均符合WS 76-2017[3]的要求,这说明新安装设备的应用质量满足目前使用状况。不同型号DR机的管电压指示偏离大小与设定的电压大小并无直接关系,需要注意的是,在检测过程中,射野大小应包含整个检测探头的有效位置,才能确保检测结果的客观、准确。同时,管电压的检测需要严格按照国家标准的要求设置检测条件,特别是不同焦点下电流的设置条件。从输出量重复性和曝光时间指示的偏离结果来看,新设备重复测读结果和曝光时间控制的稳定性良好,新安装的设备能够有效控制曝光时间,进而保证输出剂量的准确性。除去需要建立基线值的专项检测指标外,其余检测指标的检测结果均满足WS 521-2017[4]的要求。

    暗噪声主要是检测DR系统探测器在未接受到信号时所能成像的能力。探测器剂量指示是在一定层度上反映探测器后续使用过程中曝光指数的变化程度,代表着系统探测器成像能力的衰减度。本研究结果显示,不同型号的DR探测器的暗噪声和剂量指示范围相差较大,主要是不同厂家的设备在读取预处理图像后,处理数据的功能不一致,后续检测只需依据建立基线值的测试条件进行即可。现场检测发现,部分型号的探测器依据标准给出的测试条件未能成像,既然是验收检测,建议适当增加曝光条件的电压和电流,得到可以成像的最低剂量测试条件,进而建立基线值供后续检测所用。测距误差的结果说明成像距离指示效果良好。不过检测时发现,不同厂家的探测器在不同部位成像后对图像有自校准功能,建议后期采用统一的检测条件。另外,如果铅尺未能放在探测器表面,应对测量结果进行修正。为了方便后续的极限空间分辨力和低对比度细节结果能够与基线值进行比较,建议检测报告中补加与检测模体和测试条件相对应的说明,如使用线对卡的量程范围、相邻细节的对比度和直径(个数)等。提高分辨力水平,有利于临床放射工作者观察患者和受检者的影像资料,进而便于准确判断。

    信号传递特性是描述影像探测器成像区域的像素值与探测器接受的入射空气比释动能的相互关系。结果表4中给出了多种型号的拟合公式和决定系数,便于后续检测有所参照。需要注意的是,测量的空气比释动能与计量校准部门给出的校准因子进行拟合后的结果才是客观的。AEC性能测试,需要用1 mm厚铜板挡住遮线器,本研究中主要记录的是操作界面最容易得到的电流和空气比释动能的变化程度。检测AEC性能需要注意选择曝光的位置(附加滤过、电离室灵敏度等会随位置变化而变化)和影像探测器距离的统一,建议采用工程模式进行检测。滤线栅主要过滤大部分无用的散射线,增加图像的对比度,检测条件和检测结果也应注明是否取出滤线栅,后续检测也要注明滤线栅的使用与否和更换与否等情况。另外,采用第三方图像分析软件处理拷贝的预处理图像的结果有待后续进一步探讨。

    我们发现,医疗机构新上岗的DR技师缺少相应专业技术和相关质量控制知识,后续应多开展人员专业技术和放射防护知识培训工作,加强标准的宣贯、应用和普及力度,整体提高各机构人员对DR机质量控制工作的重视程度,确保设备处于合格、安全的状态。我们对DR机开展验收检测研究工作,描述了新安装设备的应用质量状况,验证了新标准的可行性和实用性。目前对主流型号的DR机建立起首次检测指标的基线值和检测条件,可为后续医疗机构和技术服务机构中DR机的稳定性和状态检测提供一定的参考方法和依据,且完整记录验收检测条件和检测结果非常重要。

    利益冲突 本研究由署名作者按以下贡献声明独立开展,不涉及任何利益冲突。

    作者贡献声明 翟贺争负责论文的设计、数据的分析、论文的撰写和修改;高杰、王鑫、吴香君负责数据的测量、收集和整理;黄子祺、王曼瑶负责设备的使用记录和质量控制;张文艺、武权负责论文的审阅与校对。

Reference (15)

Catalog

/

DownLoad:  Full-Size Img  PowerPoint
Return
Return