Fetus Dose Estimation in Computed Tomography Procedures

Computed Tomography (CT) procedures constitute the 5% of the total diagnostic radiology and provide more than the 40% of the total dose. Patient dose depends on many factors; most of them depend on the way the procedure is performed. All around the world, there is a growing interest in studying patient dose in CT procedures in order to optimize them. If the patient is pregnant, conceptus absorbed dose can be high and radiation risks during pregnancy are well established. Uruguay has 35 CT scanners and 70.000 procedures are performed per year in a total population of 3.1 million people. However, neither patient nor conceptus doses in CT procedures have still been evaluated. The main objective of this paper is to estimate fetus/embryo absorbed doses in abdomen-pelvis CT procedures in order to make radiologists and technicians realize their responsibility in CT procedures performance, especially in pregnant and females of childbearing age. The investigation was performed in the Radiology Department of the University Hospital “Dr. Manuel Quintela”. A 41 patient sample was taken to know average technical parameters used in abdomen and abdomen-pelvis CT procedures. Methods considering CT Dose Index (CTDI) in the centre of a head phantom were applied to estimate fetus absorbed dose. Results were 22 mGy in abdomen-pelvis procedure and 3 mGy in abdomen procedure. Real values may be higher if the procedures are performed with and without contrast media (barium or iodine). Results make necessary the establishing of a radiation protection protocol of the handling of pregnant patients and females of childbearing age. For this, it is essential that radiologists and technicians receive specific education in CT radiation protection.