Assessment of Organs Mean Absorbed Dose Using a Local Phantom Radiography

Abstract

Introduction: Dose quantities have been designed to protect human beings (protection quantities) and operational quantities, by ICRU and ICRP as dose absorption varies depending on the organ or tissue density of the part of the body been irradiated (exposed). Dose absorbed by an organ
need to be measured or quantified to know the amount of dose absorbed by an organ or tissue, as various organs have their dose limits given by the ICRU and ICRP. Materials and Methods: In this study, a locally constructed in-homogeneous phantom was to measure the mean absorbed doses by the organs around the head/neck region from conventional X-ray units in Jos metropolis, Nigeria. Thermoluminescence dosimeters (LiF: Mg, Ti) TLDs were used for the measurement and the statistical analysis was performed using Microsoft excel (version 2007). Results: The results in this study falls within the acceptable dose range of the organs concerned comparing with international and national findings by varying the exposure factor parameters (i.e kVp and mAs in the various X-ray units within the Jos metropolis. The mean absorbed dose by the organs from varying kV, are 0.36mSv brain, 0.21mSv eye lens, 0.42mSv thyroid, 0.25mSv heart, and 0.24 mSv lungs, for varying mAs, 0.40mSv brain, 0.25mSv eye lens, 0.43mSv thyroid 0.29mSv heart and 0.26 mSv lungs and for varying FFD (cm) 0.38 mSv brain, 0.31 mSv eye lens, 0.4 mSv thyroid, 0.26 mSv heart, and 0.25mSv lungs. Conclusion: The results for the designed phantom seemed to be applied for conventional X-ray dose validation and could be used as dose reference level for the various organs within the head/neck region.