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
