Comparison of average Water Equivalent diameter values between CTContour and vendor-specific estimates in CT dosimetry.

PURPOSE: This study aimed to compare the average Water Equivalent Diameter (WED) values obtained from CTContour, an open-source program for Size-Specific Dose Estimate (SSDE) and WED calculation, and vendor-specific values provided by Philips scanners. METHODS: A random sample of 50 adult and 50 paediatric abdomen-pelvis protocol CT images from Philips scanners were chosen at our Hospital and analysed using CTContour, and extracting average WED values from Philips from the images DICOM headers. The average WED values from the two methods were compared via Bland-Altman analysis to assess their agreement and reliability. RESULTS: The average WED values obtained from CTContour were found to be slightly lower than those obtained from the vendor-specific calculations, with mean disagreements of -5.62% and -2.88% for the adult and paediatric datasets, respectively, with both methods providing clinically acceptable estimations of average WED. There was no statistically significant correlation between body habitus and the level of disagreement between methods. CONCLUSIONS: This study demonstrates that CTContour can provide average WED measurements comparable to the vendor-specific calculations for SSDE and WED in CT dosimetry. Differences between programs are likely due to inherent differences in the methods employed to estimate WED automatically. Further research is warranted to validate these results for additional CT protocols beyond abdomen-pelvis studies.