Читать книгу Managing Medical and Obstetric Emergencies and Trauma - Группа авторов - Страница 95

Imaging using ionising radiation is often part of the management of seriously ill patients. Patients and healthcare workers are often concerned that the doses of radiation used may be harmful to the fetus (Table 5A.2). A chest X‐ray confers a minimal amount of radiation to the fetus and is the equivalent of 1 week of background radiation in London. If a chest X‐ray is clinically indicated as a first line investigation in chest pain or breathlessness it should be performed.

Table 5A.2 Safety of different imaging techniques

Investigation	Radiation dose (mGy)	First trimester	Breastfeeding
Chest X‐ray	<0.01	Safe	Safe
CT head scan*		Safe	Avoid
MRI head scan*		Avoid	Safe
CTPA*	<0.13	Safe	Avoid
V/Q scan		Safe	Avoid
CT abdomen*		Safe	Avoid
Ultrasound		Safe	Safe

^* Express and discard breastmilk for 24 hours if using contrast.

Ultrasound, computed tomography (CT) scans of the head and chest and magnetic resonance imaging (MRI) are safe throughout pregnancy. Gadolinium contrast should be avoided.

For women with suspected pulmonary embolism and a normal chest X‐ray, a lung perfusion scan should be requested in preference to CT pulmonary angiography (CTPA) because the radiation dose to maternal lung and breast tissue is lower.