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- Study of scattered radiation during fluoroscopy in hip surgeryPublication . Lesyuk, Oksana; Sousa, Patrick Emmanuel; Rodrigues, Sónia; Abrantes, António; Almeida, Rui; Pinheiro, João; Azevedo, Kevin; Ribeiro, Luís PedroObjective: To measure the scattered radiation dose at different positions simulating hip surgery. Materials and Methods: We simulated fluoroscopy-assisted hip surgery in order to study the distribution of scattered radiation in the operating room. To simulate the patient, we used a anthropomorphic whole-body phantom, and we used an X-ray-specific detector to quantify the radiation. Radiographs were obtained with a mobile C-arm X-ray system in continuous scan mode, with the tube at 0° (configuration 1) or 90° (configuration 2). The operating parameters employed (voltage, current, and exposure time) were determined by a statistical analysis based on the observation of orthopedic surgical procedures involving the hip. Results: For all measurements, higher exposures were observed in configuration 2. In the measurements obtained as a function of height, the maximum dose rates observed were 1.167 (± 0.023) µSv/s and 2.278 (± 0.023) µSv/s in configurations 1 and 2, respectively, corresponding to the chest level of health care professionals within the operating room. Proximal to the patient, the maximum values were recorded in the position occupied by the surgeon. Conclusion: We can conclude that, in the scenario under study, health care professionals workers are exposed to low levels of radiation, and that those levels can be reduced through the use of personal protective equipment.
- Anode heel effect attenuation in lumbar spine radiography: can the use of aluminium filters improve clinical practice of radiographers?Publication . Ribeiro, Luís Pedro; Abrantes, António; Lesyuk, Oksana; Dores, Rúben; Sousa, Patrick; Rodrigues, Sónia; Almeida, Rui; Azevedo, Kevin; Soares, Joana; Aleixo, JoãoPurpose: 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.