Anode heel effect attenuation in lumbar spine radiography: can the use of aluminium filters improve clinical practice of radiographers?

Purpose: The aim of this study was to design an aluminiumbased fi lter to reduce the anode heel eff ect in lumbar spine radiographs. Methods: Initially, lumbar spine examinations were observed in a public imaging department to determine standard exposure parameters. Then, the characterization of the anode heel eff ect was made using the Unfors Xi R/F detector and, based on the data collected, aluminium fi lters were designed with a wedge shape and 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 fi lters, using the universal dosimeter UNIDOS E equipped with an ionization chamber. Finally, 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 fi lter number 2, which presents a signifi cant variation of 9% between the cathodic and anodic side. This fi lter contributes to ESD reduction of 35% and 36% for AP and lateral projection, respectively. Also, according to radiographers and radiologists, it improves the image quality of lumbar spine radiography. Conclusion: The use of aluminium fi lters can be advantageous in the clinical practice of radiographers when performing lumbar spine radiographs since it allows the standardization of the anode heel eff ect, reduces the radiation dose to the patient and does not compromise image quality.