JAMA：先进的诊断性成像及相关的辐射接触有了大幅的增加

芝加哥–据6月13日刊《美国医学会杂志》JAMA上的一项研究披露，在1996-2010年间，在6个大型的综合医疗保健系统中，先进的诊断性成像的使用有了大幅的增加，其中包括电脑断层扫描的使用增加了近3倍及核磁共振成像的使用增加了近4倍，而预计的辐射接触也有了显著的增加。

根据文章的背景资料：“在过去的20年内，医疗保险人群中的诊断性成像的使用有了显著的增加，特别是那些昂贵的诸如电脑断层扫描（CT）、核磁共振成像（MRI）及核医学的正电子发射断层扫描（PET）等新技术的使用。这些先进的诊断性成像技术的研发和改进因为使用非侵入性的技术带来更早及更精确的诊断而广受赞誉。”文章的作者指出，电脑断层扫描及核医学检查会比常规性放射线发送出的电离辐射剂量高得多，且有证据显示这一辐射水平范围内的辐射接触与辐射诱发的癌症的产生有关联。

加州大学旧金山分校的Rebecca Smith-Bindman， M.D.及其同事开展了一项研究，旨在对成像使用的趋势及在综合医疗保健系统中的成员的相关辐射接触进行评估。这项研究是对来自美国不同地区的6个大型综合性医疗保健系统成员的电子记录所做的一项分析组成的。对医疗记录的审查使得人们可以对来自某些选择性检验的辐射接触量进行估计。从1996年至2010年，每年被纳入的成员-患者在1百万至2百万人之间。在该研究期间，加入者所接受的成像检查总数为3090万个，这反映了每年每人平均做了1.18次检测，其中有35%的检测与先进的诊断性成像（即：CT、MRI、核医学及超声波）有关。

研究人员发现，放射性成像及血管造影/荧光镜检查的使用率随着时间的推移而相对稳定：放射性成像每年增加了1.2%，血管造影/荧光镜检查每年下降了1.3%。“相反，先进的诊断性成像的使用则出现了明显的变化。电脑断层扫描检查增加了三倍（从1996年的1000名加入者中有52人至2010年时的1000名加入者中有149人，年增长率为7.8%）；MRIs增加了四倍（从17/1000至65/1000，年增长率为10%）；超声波检查同期增加了约2倍（134/1000至230/1000，年增长率为3.9%）。核医学的使用率有所下降（从32/1000至21/1000，年度下降率为3%），尽管在2004年后，PET成像的使用率从每1000名加入者中的0.24人增加至每1000名加入者中有3.6人，年增长率为57%。”

文章的作者还发现，CT使用率的增加与估计的辐射接触量的增加有关，人均有效剂量从1996年时的1.2 mSv增加至2010年时的2.3 mSv。在整个的多年研究中，在某一特定的年份中，那些接受了高剂量(> 20-30 mSv) 或非常高剂量辐射 (> 50 mSv) 的加入者也大约增加了2倍。研究人员还估计，截止到2010年，有2.5% 的加入者每年所接受的辐射剂量高于20至50 mSv，有1.4%的人每年接受了大于50 mSv的非常高的辐射剂量。截止到2010年，那些接受了超过20-50mSv的高剂量辐射成像的病人占了6.8%，而在该单一的年份中，那些接受了超过50mSv的非常高剂量辐射的病人占了3.9%。

doi:10.1001/jama.2012.5960
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Use of Diagnostic Imaging Studies and Associated Radiation Exposure for Patients Enrolled in Large Integrated Health Care Systems, 1996-2010

Rebecca Smith-Bindman, MD; Diana L. Miglioretti, PhD; Eric Johnson, MS; Choonsik Lee, PhD; Heather Spencer Feigelson, PhD, MPH ; Michael Flynn, PhD; Robert T. Greenlee, PhD, MPH; Randell L. Kruger, PhD; Mark C. Hornbrook, PhD; Douglas Roblin, PhD; Leif I. Solberg, MD; Nicholas Vanneman, MA; Sheila Weinmann, PhD; Andrew E. Williams, PhD

Context Use of diagnostic imaging has increased significantly within fee-for-service models of care. Little is known about patterns of imaging among members of integrated health care systems. Objective To estimate trends in imaging utilization and associated radiation exposure among members of integrated health care systems. Design, Setting, and Participants Retrospective analysis of electronic records of members of 6 large integrated health systems from different regions of the United States. Review of medical records allowed direct estimation of radiation exposure from selected tests. Between 1 million and 2 million member-patients were included each year from 1996 to 2010. Main Outcome Measure Advanced diagnostic imaging rates and cumulative annual radiation exposure from medical imaging. Results During the 15-year study period, enrollees underwent a total of 30.9 million imaging examinations (25.8 million person-years), reflecting 1.18 tests (95% CI, 1.17-1.19) per person per year, of which 35% were for advanced diagnostic imaging (computed tomography [CT], magnetic resonance imaging [MRI], nuclear medicine, and ultrasound). Use of advanced diagnostic imaging increased from 1996 to 2010; CT examinations increased from 52 per 1000 enrollees in 1996 to 149 per 1000 in 2010, 7.8% annual increase (95% CI, 5.8%-9.8%); MRI use increased from 17 to 65 per 1000 enrollees, 10% annual growth (95% CI, 3.3%-16.5%); and ultrasound rates increased from 134 to 230 per 1000 enrollees, 3.9% annual growth (95% CI, 3.0%-4.9%). Although nuclear medicine use decreased from 32 to 21 per 1000 enrollees, 3% annual decline (95% CI, 7.7% decline to 1.3% increase), PET imaging rates increased after 2004 from 0.24 to 3.6 per 1000 enrollees, 57% annual growth. Although imaging use increased within all health systems, the adoption of different modalities for anatomic area assessment varied. Increased use of CT between 1996 and 2010 resulted in increased radiation exposure for enrollees, with a doubling in the mean per capita effective dose (1.2 mSv vs 2.3 mSv) and the proportion of enrollees who received high (>20-50 mSv) exposure (1.2% vs 2.5%) and very high (>50 mSv) annual radiation exposure (0.6% vs 1.4%). By 2010, 6.8% of enrollees who underwent imaging received high annual radiation exposure (>20-50 mSv) and 3.9% received very high annual exposure (>50 mSv). Conclusion Within integrated health care systems, there was a large increase in the rate of advanced diagnostic imaging and associated radiation exposure between 1996 and 2010.