Study on image quality optimization of abdominal digital radiography with different additional filters / 中华放射医学与防护杂志

ABSTRACT

Objective:To investigate the effect of different additional filters on the image quality and radiation dose in abdominaldigital radiography (DR).Methods:Retrospective analysis was performed on 10 cases of abdominal DR from December 2020 to January 2021 in Fuxing Hospital, and the average mAs was calculated. Using automatic exposure control (AEC) technology, a polymethyl methacrylate (PMMA) slab of the corresponding thickness (18 cm) at the same output of above mAs was confirmed and used as the attenuator to simulate the abdomen. The phantom of CDRAD 2.0 and 17 slices of 10 mm thick PMMA plates (total thickness 18 cm) were placed on the bed. The additional filters were selected as no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mmAl respectively. The AEC levels were selected at -2, -1, 0, 1, and 2 respectively. The images were collected and analyzed by using CDRAD 2.0 software to obtain the image quality factor (IQF inv). The incident air kinetic energy on the surface of the PPMA was measured for each exposure, and PCXMC software was used to estimate the organ dose and effective dose, and a comparative analysis was made. Results:The skin incident doses at no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mm Al were (0.546 1±0.200 8), (0.376 2±0.133 8 ), (0.285 3±0.100 1) and (0.289 9±0.099 2) mGy, respectively. The estimated effective doses were (79.63±29.24)×10 -3, (71.05±25.56)×10 -3, (63.58±22.18)×10 -3 and (67.64±23.11)×10 -3 mSv, respectively. The gonadal doses were (0.058 1±0.020 8), (0.050 0±0.018 0), (0.044 8±0.015 6) and (0.047 7±0.016 3) mGy.The IQF inv values were 4.70±0.61, 4.80±0.84, 4.60±0.55, 4.60±0.60, respectively. There were linear correlations between the effective dose and the skin incident dose under different additional filtration, and the effective doses increased with the increase of the incident doses. The dose was lowest at the addition filtration of 0.1 mmCu+ 1 mmAl. There was no significant difference in the IQF inv between groups( P>0.05). Conclusions:The optimal additional filtration for abdominal DR was 0.1 mmCu+ 1 mmAl with the image quality meeting the requirements of clinical diagnosis, the radiation dose reduced reasonably, and the objective of the optimization of radiographic parameters achieved.