Monitoring clinical exposure index and deviation index for dose optimization based on national diagnostic reference level: Focusing on general radiography of extremities

Abstract

BACKGROUND:

The International Electrotechnical Commission established the concept of the exposure index (EI), target exposure index (EI_T) and deviation index (DI). Some studies have conducted to utilize the EI as a patient dose monitoring tool in the digital radiography (DR) system.

OBJECTIVE:

To establish the appropriate clinical EI_T, this study aims to introduce the diagnostic reference level (DRL) for general radiography and confirm the usefulness of clinical EI and DI.

METHODS:

The relationship between entrance surface dose (ESD) and clinical EI is obtained by exposure under the national radiography conditions of Korea for 7 extremity examinations. The EI value when the ESD is the DRL is set as the clinical EI_T, and the change of DI is then checked.

RESULTS:

The clinical EI has proportional relationship with ESD and is affected by the beam quality. When the clinical EI_T is not adjusted according to the revision of DRLs, there is a difference of up to 2.03 in the DI value and may cause an evaluation error of up to 1.6 times for patient dose.

CONCLUSIONS:

If the clinical EI_T is periodically managed according to the environment of medical institution, the appropriate patient dose and image exposure can be managed based on the clinical EI, EI_T, and DI.