Performing nuclear medicine examinations in pregnant women

The number of nuclear medicine examinations performed worldwide has been steadily increasing over the last few years. By consequence, an ever increasing number of pregnant women are likely to be exposed to radioisotopes. The range of doses encountered in nuclear medicine practice is well below the threshold for deterministic effects, such as embryonic death, birth defects or mental retardation. According to the linear no-threshold hypothesis, however, stochastic effects (e.g. an increased risk of cancer) remain possible even at this dose range. This purely hypothetical radiation risk to the fetus should however be put in perspective with the risk of having a scan of low diagnostic quality for a life-threatening medical condition. In recent years there has been a push to reduce as much as possible the dose from radiological imaging, for example by using acquisition protocols specific to pregnant women and by injecting lower activities. These approaches, in our opinion, overweigh the radiation risk and actually may put the life of both the mother and the fetus in danger. Since imaging protocols already seek to use the lowest possible dose compatible with a quality scan for all patients, pregnant women should be imaged using the protocols applied to any other patient. Encouraging bladder voiding by natural means after injection will significantly reduce fetal exposure without compromising image quality.