Background: Computed tomography (CT) is essential in pediatric imaging but requires careful dose optimization due to children?s increased radiosensitivity and longer life expectancy. This study estimated effective radiation dose (ED) in pediatric and adolescent patients using a 128-slice MDCT scanner at a tertiary care hospital in South India, assessing age and scan-region influences to guide standardized low-dose protocols. Methods: In this prospective study, 75 patients (<18 years) underwent head, thorax, or abdomen CT scans on a 128-slice GE Revolution scanner. ED was calculated from dose-length product (DLP) using age- and region-specific conversion factors. One-way ANOVA assessed dose differences among regions, and Pearson?s correlation evaluated age-related trends. Results: Mean EDs were 2.63 +- 0.88 mSv for head, 3.5 +- 1.37 mSv for thorax, and 4.38 +- 1.08 mSv for abdomen, with significant differences across regions (ANOVA P < 0.001). Age correlated strongly with ED for head scans (r 5 0.639, P < 0.001) and moderately for thorax scans (r = 0.503, P = 0.020), but no significant correlation was found for abdomen scans. Discussion: Optimized pediatric-specific protocols on a 128-slice MDCT scanner effectively reduced radiation doses while maintaining diagnostic image quality. The observed age-related increases in ED for head and thorax highlight the need for continuous protocol refinement, age-adjusted parameters, and institutional standardization to ensure radiation safety. Conclusion: Age- and region-tailored pediatric CT protocols on modern MDCT systems can significantly reduce radiation exposure without compromising diagnostic quality. These findings support implementing ALARA-based, evidence-driven protocols to improve safety in pediatric imaging.  Kulcsszavak: radiation dosage, pediatric radiology, dose-response relationship, radiation protection, diagnostic imaging, multidetector computed tomography