IAEA: Recurrent Imaging Accumulate Hazardous Cumulative Effective Doses

The International Atomic Energy Agency launched the Recurrent Imaging webpage on radiation protection of patients.

Millions of patients globally benefit from diagnostic imaging and image guided interventional procedures every day. The increased awareness of radiation doses and risks associated with these medical  procedures led to actions improving implementation of two key radiation protection principles, justification and optimization of individual examinations.

Following assessments carried out by the Massachusetts General Hospital (MGH), Boston, wherein several thousands of patients were found to have cumulative effective doses (CED) ≥100 mSv, a joint project was launched by IAEA and MGH to assess the situation in other parts of the world. This project covered 3.2 million patients who underwent recurrent CT imaging over periods between 1 to 5 years in different hospitals. It concluded that the number of patients who reach CED of 100 mSv is much larger than previously known— it might involve almost one million patients per year globally.

The patients who receive such cumulative radiation doses typically need radiological imaging exams for multiple clinical indications, not only for follow-up of malignant disease or chronic conditions.

The reviews undertaken by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), International Commission on Radiological Protection (ICRP), and National Council on Radiation Protection and Measurements (NCRP) have demonstrated increase of radiation-related adverse effects (particularly cancer) at or above absorbed dose of around 100 mGy.

Following the IAEA Technical meeting on Radiation Exposure of Patients from Recurrent Radiological Imaging Procedures, scientific publications from the data presented there were published in European Radiology:

The article emphasizes that nowadays numerous patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years. This brings CED of ≥ 100 mSv received over a 5-year period, thus the radiation risk creates concern. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.

This text argues that we are in an unprecedented era, where patients undergoing multiple CT exams and receiving CED ≥ 100 mSv are not uncommon. While underscoring the need for imaging appropriateness, the consideration of the number and percent of patients with high exposures and related clinical necessities creates an urgent need for the industry to develop CT scanners and protocols with sub-mSv radiation dose, a goal that has been lingering.

It was observed by the researchers that the number of patients with CED ≥ 100 mSv is much larger than previously known or anticipated. Presented data conclude that about 3.2 million patients underwent imaging procedures over periods of between 1 and 5 years in different hospitals. It is probable that an additional 0.9 million patients reach the CED ≥ 100 mSv every year globally.

Accordingly, there is a need for urgent actions by all stakeholders to address the issue of high cumulative radiation doses to patients. The actions include development of appropriateness criteria/referral guidelines by professional societies for patients who require recurrent imaging studies, development of CT machines with lower radiation dose than today by manufacturers, and development of policies by risk management organizations to enhance patient radiation safety.

Alert values for cumulative radiation exposures of patients should be set up and introduced in dose monitoring systems.

For more information visit the new page Recurrent imaging of the IAEA website. On the webpage, in particular, webinars held by the Agency together with the European Federation of the Radiographer Societies (EFRS) are announced. And previous webinars’ records are also published.

According to IAEA.