Paediatric Clinical Indication Based Computed Tomography Dose Optimisation in Selected Imaging Centers in Kampala
Abstract
Optimizing radiation doses is crucial for safety, especially in paediatrics with radiosensitive organs.Computed tomography scans pose a global radiation protection concern due to their growing use, higher effective dose, and increased sensitivity. The calculation of volume computed tomography dose index (CTDIvol) and Dose Length Product (DLP) is crucial for determining CT radiation doses for paediatric patients during CT scan examinations.
The study aimed to optimize paediatric computed tomography doses for the selected head-clinical indications; trauma, haemorrhage, and headache in selected imaging centers in Kampala. It determined the effective doses by analyzing 75th percentile values of CTDIvol and DLP. Patients were categorized based on their weight (W), with weight groups W < 5, 5 ≤
W < 15, 15 ≤ W < 30, 30 ≤ W < 50 and W ≥ 50 kg.
This was a prospective study conducted between January and July 2021 at centers A and B. It involved 381 and 447 head CT scan examinations of paediatric patients in centers . The 75th percentile values of CTDIvol and DLP were determined using descriptive statistical analysis. Data was analyzed using mean, median, and 75th percentile values. Effective doses were calculated using k-values recommended by ICRP 103 ( Brandy et al, 2011). The majority of paediatric head CT scan examinations were performed on children in the weight groups 15 ≤ W < 30 and 30 ≤ W < 50 kg for centers A and B, respectively. The most
common clinical indication for paediatric head CT scan examination in both centers A and B was Trauma, this had 159 and 168 paediatric patients which formed a percentage of 41.7% and 37.6% at centers A and B respectively.
The institutional DRLs for center A in terms of CTDIvol and DLP were 40.8, 48.7, 52.4, 57.0 mGy and 1484, 1412, 1490, 1526 mGycm for trauma, 40.7, 44.7, 52.6, 62.0 mGy and 940, 989,1252, 1252 mGycm for haemorrhage in the weight groups 5 ≤ W < 15, 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively, 38.1, 51.5, 66.3 mGy and 1288, 1381, 1495 mGycm for headache in the weight groups 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively. The institutional DRLs for center B in terms of CTDIvol and DLP were 40.0, 46.3, 51.0, 54.6 mGy and 921, 882, 934, 1318 mGycm for trauma, 44.7, 50.0, 52.6, 49.1 mGy and 940, 940, 980, 1046 mGycm for haemorrhage in the weight groups 5 ≤ W < 15, 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively, headache were 40.3, 44.3, 68.6 mGy and 1201, 1213, 1758 mGycm in the weight groups 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively. The study found out that center A had higher DRLs than B for head-clinical indications in all weight groups, with trauma having the highest DRLs in center A, followed by headache, and then haemorrhage with the lowest in all weight groups. Whereas headache had the highest DRLs in center B, followed by haemorrhage and then trauma had the lowest. DRLs of centers A and B were higher than those of ICRP 103 in all weight groups.
The effective doses obtained from centers A and B were 6.8, 4.0, 3.3, 2.1 and 4.2, 2.5, 2.1, 1.8 mSv for trauma, 4.3, 2.8, 2.8, 1.8 and 4.3, 2.6, 2.2, 1.5 mSv for haemorrhage in the weight groups 5 ≤ W < 15, 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively, and for headache were 3.6, 3.0, 2.1 and 3.4, 2.7, 2.5 mSv in the weight groups 15 ≤ W < 30, 30 ≤ W < 50, W ≥ 50 kg, respectively. The effective doses obtained from center A were generally higher than those obtained for center B for all indications studied and in all weight groups. Trauma and haedache had the highest, while haemorrhage and trauma had the lowest effective doses in all weight groups at centers A and B, respectively. Effective doses for imaging centers A and B were higher than those of ICRP 103 in all weight groups but lower than the average annual paediatric head CT effective dose of 15 mSv. The highest overall effective doses from centers A and B were 6.8 and 4.3 mSv for trauma and haemorrhage, respectively, and all were in 5 ≤ W < 15 weight group. This led to a conclusion that paediatric patients who undergo trauma and haemorrhage CT scan examinations in centers A and B in 5 ≤ W < 15 weight group are supposed to be diagnosed for a maximum of 2 and 3 times respectively
within a year to ensure their safety.
The study suggests that more research should focus on clinical indications in paediatric CT dose optimization to align with the "As Low As Reasonably Achievable (ALARA)" principle.