ENERGY IMPARTED TO NEONATES DURING X-RAY EXAMINATIONS IN A SPECIAL CARE BABY UNIT

Neonates in a special care baby unit may receive a large number of X-r ays and their dosimetry is of particular importance. A method of calcu lating energy imparted to neonates has been developed and a survey car ried out in one unit, over a period of 18 months. Entrance dose was ca lculated from the technique factors used and measurement of tube outpu t. Technique factors were recorded by the radiographer for each exposu re taken, and output was measured both with and without an incubator p resent. Field size was determined by measurements made retrospectively from the radiograph, and a Monte Carlo simulation was used to determi ne factors for conversion to imparted energy. 119 neonates were includ ed in the survey, and the mean total energy imparted was found to be 0 .09 mJ. The maximum value was a factor of nine greater than this. The study also highlighted the potential for dose reduction with regard to better collimation and shielding.