Global Outreach for Radiation Protection Program - Research Collaboration

Patients Receiving Over 100 mSv as Cumulative Effective Dose from Recurrent CT Exams

CT dose for a defined level of diagnostic information has gone down substantially. There has been a common feeling that CT is now a low dose imaging modality. A large number of publications have assessed how a different technology or technique has helped to reduce the dose in a single CT exam to maintain same level of noise in the image or how and how much dose reduction could be achieved without affecting the diagnostic information.

Even with all these efforts, there remains a lack of information characterizing the patients who receive the highest cumulative doses from recurring CT exams. There has been little attention paid to know if a sizable number of patients in population receive cumulative effective dose (CED) of 100 mSv or more from CT exams alone. Further, it has also not been known if a significant number of patients in this dose range are in age bracket (0 to 50 years) where the radiation effects can be of concern and what is the level justified imaging in this group.

To answer all the above questions, the MGH started a multi-centric study initially in the USA and then extended to other countries through International Atomic Energy Agency (IAEA). The publications below may be referred to for details:

• Contemporary issues in radiation protection in medical imaging: introductory editorial
• Radiation risk issues in recurrent imaging
• Old enemy, new threat: you can't solve today's problems with yesterday's solution
• Assessment of patients' cumulative doses in one year and collective dose to population through CT examinations
• Patients undergoing recurrent CT scans: assessing the magnitude (Full text)
• Multinational Data on Cumulative Radiation Exposure of Patients from Recurrent Radiological Procedures: Call for Action (Full text)
• Patients undergoing recurrent CT exams: Assessment of patients with non-malignant diseases, reasons for imaging and imaging appropriateness (Full text)

• CT Is Still Not a Low-Dose Imaging Modality

• Estimates of the number of patients with high cumulative doses through recurrent CT exams in 35 OECD countries

• Is it possible to kill the radiation risk issue in computed tomography?

• Cumulative Radiation Dose From Medical Imaging in Children With Noncancerous Disease

• Multicentric study of patients receiving 50 or 100 mSv in a single day through CT imaging—frequency determination and imaging protocols involved

• Organ doses and cancer risk assessment in patients exposed to high doses from recurrent CT exams