A study of tube potential and current-time product on entrance skin dose of patients undergoing chest x-ray examination in hospitals in Ogun State, Nigeria

Abstract

The Entrance Skin Dose (ESD) delivered to patients at 80, 100 and 120 kVp was determined using mathematical algorithms in six hospitals in Ogun, State, South-Western, Nigeria. The effects of Tube Potential (kVp) and Current-Time Product (mAs) were investigated in Chest Post-Anterior (PA) radiography, which is the most widely performed radiographic examination in Nigeria. This study revealed that dose reduction can be achieved at highkVp (90 - 140kVp) by careful selection of appropriate current-time product. The results obtained showed that increasing tube potential from 80-92 kVp revealed a decrease of about 33.3% in mean ESD of patients, increase from 100 to 115 kVp resulted in a decrease of 67.1% while increase from 120-138 kVp led to about 48.7% decrease in ESD estimated for patient. Reducing mAs from 5 mAs to 2 mAs showed approximately 61% decrease in ESD with the image quality still preserved. The study confirmed dose reduction by appropriate combination of both kVp and mAs.