Dealing with pregnancy in radiology: a thin line between science, social and regulatory aspects.

Numerous pregnant patients andradiation workers are exposed toionising radiation each year fromroutine radiological examinations. Itis not uncommon for a patient torequire diagnostic imaging duringthe course of her pregnancy or formaternal disorders that may jeop -ardize the foetus. Also, inadvertentfoetal exposures do occasionallyoccur in the early stages when themother-to-be is not yet aware of herpregnancy. The participation of anunborn child in a radiological studycan be an emotional experience forboth the mother and her physicians.The word “radiation” understand -ably invokes fear and uncertainty.Lack of knowledge about radiationdoses and -effects from both ionis -ing (X-rays) and non-ionising radia -tion (MRI) is responsible for greatanxiety and probably unnecessaryterminations of pregnancies. Formany patients, the exposure isappropriate; while for others theexposure may be inappropriate,placing the unborn child at increasedrisk (1). The risk of not making thediagnosis due to reasons of radia -tion protection can be higher thanthe radiation risk involved. Also themanagement of a pregnant radiolo -gy worker is not straightforward.Thefact that a worker is pregnant auto -matically involves additional protec -tion but does not necessarily meanthat she has to avoid working withmedical physicist experienced indosimetry of radiological applica -tions, if exposure details are avail -able.These occasional investigationsare simplified if the systems areincluded in a quality assurance sys -tem as described in the KB or AR ofJuly 20, 2001 (2). Conceptus dosemainly depends on the applied x-rayprocedure (e.g. radiography, pulsedfluoroscopy, CT), technical factors(photon energy, intensity and time),geometrical description, number ofprojections, patient anatomy includ -ing the thickness of the patient,whether the uterus is ante- or retro -verted, and even the distension ofthe bladder. Conceptus dose during the firsttwo months of pregnancy can beapproximated by estimating theaverage dose to the non-pregnantuterus (i.e. before its size and shapechange significantly). As pregnancyadvances, the absorbed dosebecomes less uniform and correc -tion factors for converting uterusdose to conceptus dose should betaken into account (3). For all typesof x-ray exposures (such as CT-scans,radiography, fluoroscopy) organdoses of the exposed person, includ -ing the absorbed dose to the uterus,have been discussed in literature.These data are usually generatedfrom Monte Carlo particle simula -tions that track millions of photonhistories in a medium or object for aspecific geometrical description withspecific exposure parameters.Besides the absorbed dose from theprimary x-ray beam, these simula -tions also take into account the con -ceptus dose from scattered radiationthat is emanating from exposedregions outside the pelvic area. In aparticular radiological practice, theionising radiation completely, or thatshe must be prevented from enter -ing or working in radiation areas.Pregnancy in radiology involvesmuch more than radiation protectionconsiderations (including regulatoryaspects) alone. It is complicated byindividual ethical, moral and socio-economic issues. This review paperis intended to inform radiology man -agers, radiologists, technologistsand referring clinicians in their man -agement with pregnant patients andco-workers. The paper describesconceptus doses for both patientand worker that are associated withradiology practice, reviews the risksand effects of in utero irradiation,and discusses current national poli -cies, international guidelines andpractical aspects.