Radiation Exposure from Medical Imaging: are Doses in the Carcinogenic Range?

描述(申请人提供)：在过去的十年中，医学成像的使用急剧增加，特别是使用计算机断层扫描(CT)进行成像。将CT整合到常规护理中对患者的健康产生了非常积极的影响，CT的发展被广泛认为是医学上最重要的进步之一。然而，与CT相关的辐射剂量是相当大的。例如，胸部CT可以提供常规胸部X光辐射剂量的50-500倍。因此，随着CT使用率的增加，医用电离辐射的暴露也明显增加。广泛的流行病学证据表明，暴露于电离辐射与辐射诱发的癌症的发生有关，特别是对辐射敏感的器官，如甲状腺、乳腺和造血系统。单个患者的风险可能相对较小；但许多人每年都会接触到辐射，每次检查都会受到越来越大的辐射，因为成像技术的进步和多阶段研究的使用。这可能会转化为许多癌症病例，直接由与成像相关的辐射引起。此外，接受重复医学成像的患者和接受任何成像的儿童可能面临特别高的风险。重要的是要了解通过医学成像传递的辐射，这样成像的潜在危害才能与其好处进行权衡。关于美国目前暴露在医疗辐射中的数据很少。了解医用辐射暴露是制定合理战略以最大限度减少不必要辐射的关键第一步。拟议研究的目的是查明涉及电离辐射暴露的诊断性医学成像的利用模式；定量估计与医学成像有关的电离辐射的年平均暴露量，并查明与接受特别高剂量辐射有关的患者和医生因素。为了实现这些目标，我们将对参加Group Health的患者进行回顾性队列分析。Group Health是一家位于华盛顿州西雅图的大型混合模式非营利性医疗系统，其50万名成员在1993至2007年间接受了约650万次成像测试。Group Health收集和存储自动化数据，包括详细的临床记录，以及由所有专科医生进行的所有放射成像的适应症和结果。使用这个基于人群的大型数据库，我们将描述随着时间的推移诊断成像的模式，估计与成像相关的辐射剂量的时间趋势，并确定与最高暴露于医学成像辐射相关的因素。完成这些目标将提供与医学成像相关的辐射问题的严重程度的量化数据。此外，如果我们证实群体健康数据可以用于此类研究，未来的研究将使用群体健康数据来评估与电离辐射相关的癌症的相对风险。这项研究的最终目标是帮助将医疗暴露于电离辐射降至最低。与公共卫生相关：在过去的十年里，医学成像的使用急剧增加，特别是使用计算机断层扫描(CT)成像，最初被称为计算机化的轴向断层扫描(CAT)。将CT整合到常规护理中，改善了患者的健康，而CT的发展被广泛认为是医学上最重要的进步之一。然而，大量的辐射剂量与CT有关。例如，胸部CT可以提供常规胸部X光辐射剂量的50-500倍。因此，随着CT使用的增加，医疗暴露在电离辐射中的数量也显着增加。许多流行病学证据表明，暴露于电离辐射与辐射诱发癌症的发生有关。关于美国目前暴露在医用辐射中的数据很少。了解医用辐射暴露是制定合理策略以最大限度减少不必要辐射的关键第一步。拟议研究的目的是查明涉及电离辐射暴露的诊断性医学成像的使用模式；估计与医学成像有关的电离辐射的年平均暴露量；以及确定与接受特别高剂量辐射有关的患者和医生因素。随后的研究将量化那些从医学成像中接受特别高剂量辐射的个人患癌症的相对风险增加的程度。完成提议的目标将有助于测量与医学成像相关的辐射问题。这项研究的最终目标是帮助将医疗暴露于电离辐射降至最低。。

DESCRIPTION (provided by applicant): The use of medical imaging has increased dramatically over the last decade, particularly imaging with computed tomography (CT). Integrating CT into routine care has had an extremely positive impact on patient health, and the development of CT is widely considered one of the most important advances in medicine. However, the radiation doses associated with CT are substantial. For example, a chest CT can deliver 50-500 times the radiation dose of a routine chest x-ray. Therefore, along with the increased utilization of CT has come a marked increase in the medical exposure to ionizing radiation. Extensive epidemiological evidence has linked exposure to ionizing radiation with development of radiation-induced cancers, particularly to radiation-sensitive organs, e.g., the thyroid, breast, and hematopoetic systems. The risk to an individual patient is probably relatively small; but many people are exposed annually, with increasingly large exposures per examination from technological advances in imaging and the use of multiple-phase studies. This could translate into many cancer cases resulting directly from the radiation associated with imaging. Additionally, patients who undergo repeated medical imaging, and children who undergo any imaging, may be at particularly high risk. It is important to understand the radiation delivered through medical imaging, so this potential harm of imaging can be weighed against its benefits. Few data are available regarding current exposure to medical radiation in the United States. Understanding exposures to medical radiation is a crucial first step to develop reasonable strategies to minimize unnecessary exposure. The aims of the proposed study are to identify patterns in the utilization of diagnostic medical imaging that involves exposure to ionizing radiation; to quantitatively estimate average annual exposures to ionizing radiation associated with medical imaging and to identify patient and physician factors that are associated with the receipt of particularly high doses of radiation. To pursue these aims, we will conduct a retrospective cohort analysis of patients enrolled in Group Health, a large, mixed-model, nonprofit, healthcare system in Seattle, WA, whose 500,000 members underwent approximately 6.5 million imaging tests between 1993 and 2007. Group Health collects and stores automated data, including detailed clinical records, and the indication and result of all radiological imaging, conducted by physicians of all specialties. Using this large, population-based database, we will describe patterns of diagnostic imaging over time, estimate temporal trends in radiation doses associated with imaging, and determine factors associated with having the highest exposure to medical imaging radiation. Completing these aims will provide quantitative data on the magnitude of the problem of radiation associated with medical imaging. Further, if we validate that Group Health data can be used for such research, future studies will use Group Health data to evaluate the relative risk of cancer associated with ionizing radiation. The ultimate goal of this research is to help keep medical exposure to ionizing radiation to a minimum. PUBLIC HEALTH RELEVANCE: The use of medical imaging has increased dramatically over the last decade, particularly imaging with computed tomography (CT), originally called computerized axial tomography (CAT) scans. Integrating CT into routine care has improved patient health and the development of CT is widely considered one of the most important advances in medicine. However, substantial radiation doses are associated with CT. For example, a chest CT can deliver 50-500 times the radiation dose of a routine chest x-ray. So along with the increased use of CT has come a marked increase in the medical exposure to ionizing radiation. Much epidemiological evidence has linked exposure to ionizing radiation with development of radiation-induced cancers. Little data are available about current exposure to medical radiation in the United States. Understanding exposures to medical radiation is a crucial first step toward developing reasonable strategies to minimize unnecessary exposure. The aims of the proposed study are to identify patterns in the use of diagnostic medical imaging that involves exposure to ionizing radiation; to estimate average annual exposures to ionizing radiation associated with medical imaging; and to identify patient and physician factors associated with receiving particularly high doses of radiation. Subsequent research will quantify the increased relative risk of developing cancer among individuals who have received particularly high doses of radiation from medical imaging. Completing the proposed aims will help measure the problem of radiation associated with medical imaging. The ultimate goal of this research is to help keep medical exposure to ionizing radiation to a minimum. .