Anode Heel Effect Attenuation in Lumbar Spine Radiography: Can the Use of Aluminium Filters Improve Clinical Practice of Radiographers?

Abstract

Purpose: The aim of this study was to design an aluminium-based filter to reduce the anode heel effect in lumbar spine radiographs. Methods: Initially, lumbar spine examinations were observed in a public imaging department to determine the standard exposure parameters. Then, the characterization of the anode heel effect was made using the Unfors Xi R/F detector and based on the data collected, aluminium filters were designed with a wedge shape, with thicknesses ranging from 0.1 to 4.0 mm. The assessment of the entrance skin dose (ESD) reduction was performed on the anthropomorphic phantom, with and without filters, using the universal dosimeter UNIDOS E equipped with an ionization chamber. Lastly, the image quality assessment was performed with the Pehamed Phantom Digrad A+K and image quality surveys were applied to radiographers and radiologists. Results and Discussion: Uniformity of the beam was achieved, especially with the filter number 2, which presents a significant variation of 9% between cathode and anode side. This filter contributes to ESD reduction of 35% and 36% for AP and lateral projection, respectively. Also, according to the radiographers and radiologists, it improves the image quality of lumbar spine radiography. Conclusion: The use of aluminium filters can be advantageous in the clinical practice of radiographers when carrying out lumbar spine radiographs, since it allows to standardize the anode heel effect, reducing the radiation dose to the patient and without compromising the image quality.