The relationship between the Exposure Index Error Compared to the Lifetime of the Radiographic Image Detector

Abstract

Exposure Index (EI) is a quantity that indicates the effectiveness of a digital imaging detector for generating an image when exposed to X-rays. According to IEC 62494-1:2008 standard for the good performance image detector, there must be an error in the EI value displayed by the image detector not more than 20 percent compared to the standard EI value. The standard EI value is calculated from the radiation dose in microgray [µGy] multiplied by 100. In order to control the quality of the digital radiographic imaging detector, this research therefore conducted an experiment to find the trend of changing the error value of EI when the digital radiographic image detector is used continuously. The data on EI values were collected from the Konica Minolta AeroDR P-52 image detector (AeroDR2 1417S) at the Regional Health Promotion Center 7 Khonkaen, with a lifetime starting from 1 year to 6 years. The collection of EI data is carried out under conditions of generating quality X-rays according to the RQA5 standard in IEC 61267:2005. The results show that the error of the EI value of the image detector is a linear change with an error rate of +0.8 percent per year. If the deterioration of this image detector continues to linear change, this image detector can be used for up to 23 years. However, more data must be collected to show how long linear deterioration of the image detector can continue.