An effective dose-reducing tool in digital radiography for lateral lumbar spine examination.

Abstract

Objectives: The lateral lumbar spine examination is a frequent radiographic projection, which involves relatively high radiation dose and hence a_ substantial contributor to collective dose; This regard has urged the researcher to investigate dose-reducing techniques which apart from reducing the patient dose, do not compromise the image quality. Many techniques are available to reduce the dose to patients, one of which involves increasing the Source to Image Distance (SID), referring to an increase in the distance between the patient and the X-ray tube during an imaging procedure. This technique involves no extra costs and is simple and effective at reducing diagnostic X-ray doses. Method: Results: In order to test the effectiveness of increasing the SID as a dose reducing tool, the study involved the use of an anthropomorphic phantom which was imaged in the lateral lumbar spine position at 100cm, 130cm and 150cm SID at varying X-ray beam energies. The entrance surface dose (ESD), effective dose (ED) and dose to the ovaries were then calculated using DoseCal Software and the image quality of the resultant radiographs was assessed by five experienced clinicians. Following statistical analysis, dose reductions of 40%, 32% and 31% were achieved for the ESD, ED and dose to the ovaries, respectively, when the SID was increased from 100cm to 130cm. Moreover, the standard (100cm) and new technique (130cm) produced the same mean weighted image quality scores. Conclusions: On the basis of this study, the researcher concluded that increasing the SID from 100cm to 130cm is an effective method of dose reduction for a lateral lumbar spine projection. The researcher recommends that this study be verified by application on patients, to compare the standard technique to the new proposed technique and encourage more studies to establish the effectiveness of increasing SID for other projections.