Paediatric Patients Dose Optimisation and Risk Assessment in Computed Tomography Examination

Abstract

The aim of the study was to establish and utilize national diagnostic reference levels (DRLs) of dose length product (DLP) and computed tomography dose index (CTDI) for routine computed tomography (CT) paediatric examinations. Additionally, the study estimated signal-to-noise ratio and lifetime attributable radiation risk. Materials used included multi-detector computed tomography machine, CT water phantom, electron density phantom, Head and Body phantoms and MeVisLab workstation. The methodology involved estimation of CTDI, DLP, cancer risk incidence (CRI) and signal-to-noise ratio (SNR) using a minimum of 20 patients dose parameters of head, chest, and abdomen- pelvis CT examinations. In all 300 images of randomly selected paediatric patients undergoing CT scans of head, chest, and abdomen-pelvis from these centres were collected of which 200 met the selection criterion and were analysed. The measured median and upper quartile CTDIvol for head CT were 6.86 and 7.33 mGy, chest CT 6.98 and 6.70 mGy, abdomen-pelvis CT 4.71 and 5.28 mGy. While DLP for head CT were 1103.00 and 1249.58 mGy-cm, chest CT were 978.86 and 1250.42 mGy-cm, abdomen-pelvis CT were 565.85 and 787.05 mGy-cm. The mean CRI was in the range of 1 in 10,000 to 4 in 1,000 for all the CT examinations. The SNR, were all above the accepted minimum of 5. The results of the CTDI, DLP, CRI and SNR were comparable to international standard values. This study recommends dose optimization of CT examination protocols to ensure that paediatric patient doses are as low as reasonably achievable by using the established CTDI and DLP as reference values for future intercomparison of data from similar studies