In this report, I will estimate the effective dose for pediatric patients undergoing a head CT scan. This study is important because children’s tissues are sensitive and they may easily have radiation-induced cancer in some glands, organs, or bones. CT scans are a better version of X-rays but with higher doses. CT scans have ionizing radiation which may interact with the tissue in many different ways. Using a mobile MOSFET is a high-efficiency detector with a small size, making it easier to measure the absorbed dose. I could measure the absorbed dose of five tissues and then I was able to calculate the effective dose.The effective doses are EMandible = 5.081 ±0.748 mSv, EThyroid = 1.850 ± 0.208 mSv, EHyoid = 0.543 ± 0.060 mSv, EL,eye = 1.426 ± 0.231 mSv, and ER,eye = 1.322 ± 0.139 mSv. These results were accepted based on the standard deviation but the effective dose is considered to be above the maximum effective dose suggested for pediatrics. The results were then compared to the effective dose estimated from the DLP which was EDLP = 6.142 mSv and EDLP = 6.409 mSv for two exposure sizes. Further studies should be done to be able to decrease the risk and maintain the image quality of CT scans.