The radiation exposure controversy

Abstract

In this issue of Acta Radiologica, Professor Ernest Pauwels from Leyden brings into focus the possible risk of radiation-induced carcinogenesis from diagnostic radiology, with particular emphasis on computed tomography (CT) (1). As a consequence of technologic advances and increasing availability, CT utilization has grown rapidly, obviously because CT is an accurate and rapid diagnostic tool. Professor Pauwels’ review is published a few months after the 25-year anniversary of the explosion at Ukraine’s Soviet-era Chernobyl nuclear plant. It seems to be a rather common understanding in the general society that the accident caused thousands of deaths as a result of radioactive contamination (2). In contrast, the official reports of UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) state that the explosion caused the death of 30 workers within a few weeks. Twenty-eight workers died in the first three months after the accident of radiation sickness, and another 19 died in 1987–2004 of various causes not necessarily associated with radiation exposure (3). The report states that there is no evidence of a major public health impact attributable to radiation exposure two decades after the accident, although many cases of thyroid cancer in children and adolescents are most likely caused by radiation exposure. Another event with focus on radiation effects in 2011 was the disastrous east Japan earthquake and tsunami of March 11 and the subsequent Fukushima nuclear power plant accident. Surprisingly, the public focus almost instantaneously shifted from the earthquake and tsunami that killed an estimated 25,000 people, to the Fukushima nuclear accident, in spite of no confirmed health effect to anyone being reported as a result of radiation exposure from the nuclear accident, according to a report of the International Atomic Energy Agency (IAEA) by June 2011 (4). In the subsequent international dispute, the German government announced a plan to shut down all nuclear reactors by 2022. These events illustrate that radiation and possible harmful effects of radiation are sensitive issues, and not necessarily knowledge-based. Therefore, Professor Pauwels’ efforts to update the radiological society on recent literature concerning potential radiation-induced disease are welcomed. Radiation exposure resulting from CT is currently a controversy, and in essence the disagreement deals with the existence of a threshold effect for radiation-induced disease or not, i.e. is there evidence of actual harm to patients resulting from diagnostic imaging? No doubt the internationally adopted ALARA (as low as reasonably achievable) principle is a reasonable approach. It is, however, our responsibility as radiologists also to be aware of the potential harm from avoiding imaging where it is indicated. Furthermore, if imaging is indicated, the radiation dose must be high enough to visualize pathology. Our efforts to reduce radiation dose must not impair image quality to an extent where significant findings are concealed by image noise.