Purpose: Children are sometimes examined with Computed
Tomography protocols designed for adults, leading to radiation doses higher
than necessary. Lack of optimisation could lead to image quality higher than
what is needed for diagnostic purposes with associated high doses to patients.
Optimising the protocols for paediatric head trauma CT imaging will reduce
radiation dose. Objective: The study aimed to optimise radiation dose
and assess the image quality for a set of protocols by evaluating noise, a contrast to noise ratio, modulation transfer
function and noise power spectrum. Methods: Somaton Sensation 64 was
used to scan the head of an anthropomorphic phantom with a set of protocols.
ImageJ software was used to analyse the paediatric head image from the scanner.
IMPACTSCAN dosimeter software was used to evaluate the radiation dose to the
various organs in the head. MATLAB was used to analyse the Modulation Transfer
Function and the Noise Power. Results: The estimated Computed Tomography
Dose Index volume (CTDIvol) increased with increasing tube current
and tube voltage. The high pitch of 0.9 gave a lower dose than
the 0.5 pitch. The eye lens received the highest radiation dose (39.2 mGy)
whiles the thyroid received the least radiation dose (13.7 mGy). There was an
increase in noise (62.46) when the H60 kernel was used and a lower noise
(8.829) was noticed when the H30 kernel was used. Conclusion: The
results obtained show that the H30 kernel (smooth kernel) gave higher values
for noise and contrast to noise ratio (CNR) than the H60 kernel (sharp kernel).
The H60 kernel produced high values for the modulation transfer function (MTF)
and noise power spectrum (NPS). The eye lens received the highest radiation
dose.
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