Effective dose is a single parameter meant to reflect the relative risk from exposure to ionizing radiation. It reflects the risk of detrimental biologic effects from a non- uniform, partial-body exposure in terms of a whole-body exposure1. In this study we applied the American Association of Physicists in Medicine (AAPM)2 dose equilibrium (DEq) method and the CTDI method to estimate organ dose and effective dose values and retrospectively correct the annual effective patient dose for a random sample of twenty patients. The results showed that the effective dose summed across the affected organs was underestimated by CTDI between 26 % and 31% when compared to the DEq estimate. This updated data set reflected that the effective dose to patients was up to 6 mSv greater than previously estimated through CTDI. 1. Rodrigo Canellas, Subba Digumarthy, Azadeh Tabari, Alexi Otrakji, Shaunagh McDermott, Efren J. Flores, Mannudeep Kalra. 2018. Radiation dose reduction in chest dual-energy computed tomography: effect on image quality and diagnostic information. Radiologia Brasileira 51:6, 377-384 2. AAPM. Report of AAPM Task Group 111: The Future of CT Dosimetry: Comprehensive Methodology for the Evaluation of Radiation Dose in X-Ray Computed Tomography. AAPM Report No. 111. City Park: American Association of Physicist in Medicine; 2010.