The effective dose and image noise in pediatric CT brain at King Chulalongkorn Memorial Hospital

Abstract

Background : CT is the standard equipment for assessing a variety of disorder in children. More than half of pediatric CT examinations at King Chulalongkorn Memorial Hospital (KCMH) are related to the brain. Nevertheless, there is no available data of pediatric radiation dose from CT brain at KCMH.

Objective : To investigate the radiation dose when CT brain is performed and compare with the previously published dose reference levels (DRLs) in order to minimize or eliminate the amount of unnecessary radiation exposure.

Design : Retrospective descriptive data.

Setting : Department of Radiology, Faculty of Medicine, Chulalongkorn University

Materials and Methods : Of the total 349 examinations in 2009, volume CT dose index (CTDI_vol), dose length product (DLP) and image noise were collected. Effective dose was accomplished by multiply DLP with age-specific conversion coefficients. Third quartile values of these parameters were compared with the German and UK DRL.

Results : CTDI_vol were lower than DRL from the UK and German in most pediatric age groups. Only 4 patients aged below 5 years old (2.3%) received higher CTDI_vol. Two out of four age groups showed greater DLP than DRL from the UK but still lower than the German value. Approximately, 21% (75/349) performed scanning more than twice in the same study. Effective dose in patients younger than 10 years demonstrated greater value which reflects overall higher DLP. Image noise displayed no difference in each age group and comparable with previous studies.

Conclusion : Most of our radiation dose parameters are within the appropriate range. However, there is a little problem with rescanning and over scan length. Stringent to CT protocol and proper prescanning evaluation may be a good solution.