Use of Clinical Exposure Index and Deviation Index Based on National Diagnostic Reference Level as Dose-Optimization Tools for General Radiography in Korea

Abstract

The International Electrotechnical Commission introduced the concepts of exposure index (EI), target exposure index (EIT) and deviation index (DI) to manage and optimize patient dose in real time. In this study, we have proposed an appropriate method for setting the EIT based on the Korean national diagnostic reference levels (DRLs). Furthermore, we evaluated the use of clinical EI, EIT and DI as tools for patient dose optimization in clinical environments by observing the changes in DI with those in EIT. According to the Korean national exposure conditions, we conducted experiments on three representative radiographic examinations (chest posterior–anterior, lateral and abdomen anterior–posterior) of clinical environments. As the exposure conditions and DRLs varied, the clinical EI, EIT and DI also varied. These results reveal that the clinical EI, EIT and DI can be used as tools for optimizing the patient dose if EIT is periodically and properly updated.

Proper Management of the Clinical Exposure Index Based on Body Thickness Using Dose Optimization Tools in Digital Chest Radiography: A Phantom Study

“…This discrepancy occurred due to the differences of digital characteristics between manually calculated and automatically displayed EI because of the differences of the digital characteristic curve used for the calculation [ 14 ]. However, the IEC standard recommended an EI uncertainty of under 20%, thus, if the displayed EI satisfied within the range of uncertainty (<20%), the digital radiation detector would be regarded as under good quality-controlled status [ 11 , 13 , 14 ]. Moreover, it is reported that prior to using the EI, understanding the characteristics of digital system is necessary [ 13 , 14 ].…”

“…However, the IEC standard recommended an EI uncertainty of under 20%, thus, if the displayed EI satisfied within the range of uncertainty (<20%), the digital radiation detector would be regarded as under good quality-controlled status [ 11 , 13 , 14 ]. Moreover, it is reported that prior to using the EI, understanding the characteristics of digital system is necessary [ 13 , 14 ]. We used two different digital systems from the same manufacture, but the clinical EI of the chest examinations did not indicate the same value.…”

“…There have been many studies on introducing EI to manage patient exposure dose and image quality, but there is a possibility of underestimating patient dose if operators run the dose managing tool using EI without any consideration of patient thickness. Park et al also reported that the clinical EI T for chest and abdomen radiography should be updated periodically as the change of exposure condition [ 13 ]. However, the interventional reference point was defined by the IEC to represent the patient skin level for evaluating and monitoring the patient dose in multi-modality [ 28 ].…”

“…Therefore, manufacturers have introduced the clinical exposure index according to each general radiographic examination (hereinafter referred to as “clinical EI”, Figure 1 b). Compared to traditional exposure indicators in digital radiography systems, the clinical EI is proportional to incident exposure dose and cannot be modified after the examination regardless of the manufacturer and type of digital radiography system [ 13 ].…”

“…Previous studies have reported the usefulness of EI, as per IEC standards, which can be achieved using a quality control tool and an effective radiation dose monitoring system. Park et al investigated the possibility of using it as a quality control tool by using displayed EI, as per IEC standards, and also revealed that the usefulness of clinical EI, EI T , and DI, which could be recorded in DICOM header tags for monitoring the ESD based on the national diagnostic reference levels (DRLs) [ 13 , 14 ]. In clinical situations, there are several trials that have introduced the clinical EI, EI T , and DI to optimize medical radiation use [ 15 , 16 , 17 ].…”