Addressing the Challenge of Managing Radiation Use in Medical Imaging: Paradigm Shifts and Strategic Priorities

March 15, 2014

The rise in utilization of medical imaging-especially computed tomography and nuclear medicine-and the issues of perceived, potential, theoretical, and known risks associated with ionizing radiation exposure from imaging have come to the forefront of public and professional awareness, raising concerns and controversies.

The rise in utilization of medical imaging-especially computed tomography and nuclear medicine-and the issues of perceived, potential, theoretical, and known risks associated with ionizing radiation exposure from imaging have come to the forefront of public and professional awareness, raising concerns and controversies. It is well established that the use of imaging with ionizing radiation and associated radiation dose have increased significantly over the past quarter century on both a national and a global scale. However, imaging has also revolutionized the way we practice medicine. Imaging procedures using ionizing radiation carry relatively small individual risks that are usually justified by the medical need in patients with symptoms or other signs of disease, especially when diagnostic information is maximized and radiation dose is minimized. This is particularly true in the field of oncology, where imaging is used nearly universally to select, plan, and/or directly guide treatment, and to perform post-treatment follow-up. Indeed, as indicated by a preliminary analysis of the benefits of just a few of its applications, justified medical imaging likely helps save countless lives every year.[1]

While the increased use of imaging examinations that are justified and optimized can be viewed as a positive development, we need to be aware of potential risk. The appropriate use of radiation in medicine has been a recognized aim since the advent of the x-ray.[2] The radiation safety principles of justification and optimization have been advocated for almost a century and have persisted as tenets of medical practice.[3-5] Therefore the responses to the increased use of ionizing radiation have included voluntary approaches to improving quality control, education, and utilization; data registries[6-8]; and legislative requirements[9] and rulemaking guidance.[10]

Goske et al[11] present important perspectives from the “Image Gently” and “Image Wisely” campaigns regarding oncology practice. These campaigns have been successful grass-roots social marketing missions that have raised awareness and that are educating a broad and ever-expanding audience. Indicators of their success include increased interactions between concerned patients and healthcare providers regarding the justification and optimization of medical imaging with ionizing radiation, as well as the interactions between several medical professions and manufacturers, which are jointly beginning to address the issues involved in concrete ways.

In addition to providing background information on the essentials of the campaigns, Goske et al[11] helpfully summarize the current understanding of imaging doses and the need for balancing benefits and risks in the oncologic setting. They also point out several opportunities for ongoing improvement. We found four of these especially compelling. First, they appropriately acknowledge that imaging goals and benefits differ greatly across the cancer care spectrum, depending primarily on the particular disease involved; this should encourage conversation and action with a disease-management-team approach at both local and national levels. Second, they emphasize that cancer risks from ionizing radiation vary significantly with age and gender and are especially important to address in younger patients. À propos of this point, the recent review of pediatric risks by the United Nations,[12] as well as the information being gleaned from the childhood survivor studies,[13] should help inform practitioners. Third, the authors correctly note that past radiation exposures themselves should not be factored into current imaging decisions, although future exposures should still be justified on the basis of assessments of benefit (the outcomes of decisions made based on the diagnostic information provided) and risk (the potential detrimental effects) and supported by consensus guidelines. The behavioral concept of a “sunk cost” incurred in the past that is mistakenly factored into decision making in the present is a key problem that is often difficult to recognize or mitigate.[14] Fourth, Goske et al[11] aptly point out that benefit-risk considerations with respect to imaging are made difficult by a lack of consistent metrics for both dose and risk.

The “Image Gently” and “Image Wisely” campaigns should be recognized as effective catalysts for changing both behavior and imaging techniques. Recent research, design, development, and implementation efforts by equipment manufacturers and professional societies have provided updated equipment and tools for reducing doses from computed tomography, fluoroscopy, and molecular imaging. Perhaps we are indeed witnessing the birth of a paradigm shift. However, generating innovation and a genuine shift in the management of radiation use in medical imaging while ensuring that we continue to fully reap its benefits is a multifaceted and long-term challenge.[15] We suggest below four priority areas in which academia, government, industry, and professional societies must lead and support strategic, comprehensive efforts. These efforts must include authentic engagement with the ultimate stakeholders-patients.

Understanding Radiation Risk

Much remains to be learned of both radiobiologic mechanisms and epidemiologic outcomes, especially at medical imaging dose levels when these are coupled with protracted exposures.[3,16-18] The United States should coordinate its strategy with the question-based radiobiology research approach of Europe,[19] while funding larger epidemiology studies at low doses[20,21] across the spectrum of ages, genders, doses, genetic profiles, shapes, and sizes. In addition, alternatives to the use of effective dose as a surrogate for risk in medicine, such as organ dose–organ risk approaches, should be seriously considered and, where possible, implemented.[22]

Justification and Utilization

It is essential that the lack of evidence regarding the direct benefits of medical imaging be addressed by the performance of well-designed, prospective studies that analyze the impact of the diagnostic information obtained from medical imaging on treatment decision making. While the availability of appropriateness criteria is essential, referring physicians need to be educated regarding the importance of using these criteria. In addition, there is a need for critical reassessment of screening and post-treatment imaging frequency and protocols, especially for pediatric patients.

Dose Optimization

There is an urgent need to develop a standardized dose specification across the imaging modalities, and recent image-based approaches need to be automated to provide specific individual patient organ doses. Gold standards and methods for assessing acceptable image noise and signal-to-noise levels for each diagnostic imaging application are required. The International Commission on Radiological Protection diagnostic reference level concept should drive prioritized dose reductions nationally, regionally, and at the level of the individual enterprise/facility.[4] To ensure continued dose reduction, manufacturers must interact openly with professional societies to illuminate and refine dose-reduction techniques instead of supplying a plethora of proprietary “black-box” approaches with confusing, nonstandardized nomenclature.[23]

Communicating Benefit and Risk

A multidisciplinary project (ie, involving physicians, communications experts, educators, behavioral scientists, and others) is needed to study, design, validate, and implement effective, shared decision-making techniques for addressing the benefits and risks of medical imaging with patients and their families.[24,25] This effort should include education of the media and the general public.

Financial Disclosure:The authors have no significant financial interest in or other relationship with the manufacturer of any product or provider of any service mentioned in this article.

References:

1. Zanzonico P. Benefits of medical radiation exposures. Available from: https://hps.org/hpspublications/articles/Benefitsofmedradexposures.html. Accessed: February 14, 2014.

2. ICRP [International Commission on Radiological Protection]. International Commission on Radiological Protection: History, policies, procedures. Oxford: Elsevier Science Ltd; 1998.

3. ICRP. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. Ann ICRP. 2007;37:1-332.

4. ICRP. Radiological protection in medicine. ICRP Publication 105. Ann ICRP. 2008;37:1-63.

5. Kase KR. Radiation protection principles of NCRP. Health Phys. 2004;87:251-7.

6. Cody DD, Fisher TS, Gress DA, et al. AAPM medical physics practice guideline 1.a: CT protocol management and review practice guideline. J Appl Clin Med Phys. 2013;14:3-12.

7. American College of Radiology. Accreditation. Available from: http://www.acr.org/Quality-Safety/accreditation. Accessed: February 12, 2014.

8. American College of Radiology. American College of Radiology dose index registry. Available from: http://www.acr.org/Quality-Safety/National-Radiology-Data-Registry/Dose-Index-Registry. Accessed: February 12, 2014.

9. State of California Legislature. Bill SB 1237: Radiation Control: Health Facilities and Clinics: Records. Effective 29 Sep 2010.

10. Joint Commission. Diagnostic Imaging Services Requirements. Available from: http://www.jointcommission.org/standards_information/prepublication_standards.aspx Accessed February 17, 2014.

11. Goske MJ, Frush DP, Brink JA, et al. Curbing potential radiation-induced cancer risks in oncologic imaging: perspectives from the ‘Image Gently’ and ‘Image Wisely’ campaigns. Oncology (Williston Park). 2014;28:232-43.

12. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Sources, effects and risks of ionizing radiation. UNSCEAR 2013 report to the General Assembly and Scientific Annexes, vol II, Scientific Annex B. Effects of radiation exposure of children. New York: United Nations; 2013.

13. St. Jude Children's Research Hospital. Childhood Cancer Survivor Study (CCSS). Available from: https://ccss.stjude.org/. Accessed: February 17, 2014.

14. Schacter DL, Gilbert DT, Wegner DM. Psychology. 2nd ed. New York: Worth Publishers; 2011.

15. Hricak H, Brenner DJ, Adelstein SJ, et al. Managing radiation use in medical imaging: a multifaceted challenge. Radiology. 2011;258:889-905.

16. Dauer LT, Brooks AL, Hoel DG, et al. Review and evaluation of updated research on the health effects associated with low-dose ionising radiation. Radiat Prot Dosimetry. 2010;140:103-36.

17. National Council on Radiation Protection and Measurements (NCRP). Uncertainties in internal radiation dose assessment. NCRP Report No. 164. Bethesda, MD: National Council on Radiation Protection and Measurements; 2010.

18. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Report of the United Nations Scientific Committee on the Effects of Atomic Radiation. Fifty-ninth session. General Assembly Official Records Sixty-seventh session, supplemental No. 46. A/67/46: New York: United Nations; 2012.

19. Averbeck, D. MELODI-Multidisciplinary European Low Dose Initiative. 4th draft of strategic research agenda (SRA). Available from: http://www.melodi-online.eu/doc/SRA4.pdf. Accessed: February 17, 2014.

20. Boice JD. A study of one million U.S. radiation workers and veterans. Health Physics News. 2012;XL:7-10.

21. EPI-CT: International pediatric CT study. Available from: http://epi-ct.iarc.fr/. Accessed: February 17, 2014.

22. Brenner DJ. We can do better than effective dose for estimating or comparing low-dose radiation risks. Ann ICRP. 2012;41:124-8.

23. American Association of Physicists in Medicine (AAPM). AAPM CT lexicon version 1.3. Available from: http://www.aapm.org/pubs/CTProtocols/documents/CTTerminologyLexicon.pdf. Accessed February 17, 2014.

24. Dauer LT, Thornton R, Hay J, et al. Fears, feelings, and facts: interactively communicating benefits and risks of medical radiation with patients. Am J Roentgenol. 2011;196:756-61.

25. American College of Radiology (ACR). ACR practice guideline on informed consent for image-guided procedures. Reston, VA: American College of Radiology; 2007.