A study on reciprocity law failure using human phantoms in digital radiography

Abstract

Background/Objectives: The purpose of this study was to analyze the subject images of the human body Phantom under the X-ray exposure condition of the DR system and to confirm the reciprocity law and the reciprocity law failure phenomenon of the soft tissues and bone tissues. Methods/Statistical analysis: After adjusting the tube current-exposure time product (mAs) to the same value, the reciprocity law was confirmed by averaging the pixel gray values at a certain position from X-rays of 3 different exposure conditions changing the tube current (mA) and exposure time (sec). Image analysis was performed using the grid and plot profile functions of the image J program to compare the reciprocity law in the thickness between the soft tissues and bone tissues. Findings: As a result, large reciprocity law failures were observed in the low bone thickness area of the foot phantom and the soft tissues with low tissue density, and the same results were found in the experiment using the abdomen phantom which has a high subject thickness. Improvements/Applications: As a result, this study confirmed that reciprocity law and reciprocity failure due to X-ray exposure may occur between human tissues in adjacent areas.