Follow‐up the severity of abnormalities diagnosed in chest CT imaging of COVID‐19 patients: A cross‐sectional study

Abstract Background and Aims This study aimed to evaluate the severity of diagnosed lung abnormalities of coronavirus disease 2019 (COVID‐19) patients based on the pre‐and postrecovery follow‐up chest computed tomography (CT) scan findings done at regular intervals. Methods This cross‐sectional study was performed in three phases. The severity of lung abnormalities was recorded and compared based on the initial and follow‐up chest CT findings carried out pre‐and at regular intervals (3 and 6 months) of postrecovery of COVID‐19 patients. Statistical data analysis was conducted using SPSS‐Version 26. Pearson Chi‐square test was used to analyze the results. p‐value < 0.05 was considered statistically significant. Results Regarding the initial chest CT findings, although ground‐glass opacity (GGO) was observed as the most common lung lesion, almost all the evaluated COVID‐19 patients had multiple lung lesions and involvements, especially with more involvement of the lower lobes. concerning the frequency of lung lesions and involvements in all phases of the study, almost no statistically significant differences were observed between male and female COVID‐19 patients and different age groups. However, older age groups had relatively more lung abnormalities due to Covid‐19 based on initial CT images which take more time to be eliminated. Lung abnormalities of Covid‐19 patients decreased significantly during the follow ups based on chest CT findings at different study phases. Conclusion According to evaluated pre‐ and post‐recovery chest CT scans, the frequency of lung lesions and lung involvement distribution decreased significantly in COVID‐19 patients, 3 and 6 months after recovery, and most of the recovered patients had no lung lesions or involvement anymore

Analytical investigation of magnetic field effects on Proton lateral deflection and penetrating depth in the water phantom: A relativistic approach

Background: Integrated proton therapy - MRI systems are capable of delivering high doses to the target tissues near sensitive organs and achieve better therapeutic results; however, the applied magnetic field for imaging, influences the protons path, changes the penetration depth and deflects the particles, laterally, leading to dose distribution variations. Objective: To determine the effects of a magnetic field on the range and the lateral deflection of protons, analytically. Methods: An analytical survey based on protons energy and range power law relation, without using small angle assumption was done. The penetration depth and lateral deflection of protons with therapeutic energy ranges 60- 250 MeV in the presence of uniform magnetic fields of 0-10T intensities, were calculated analytically. Calculations were done for relativistic conditions with Mathematica software version 7.0, and MATLAB 7.0 was applied to plot curves and curve fittings. Results: In the presence of a magnetic field, the depth of Bragg peak was decreased and it was shifted laterally. A second order polynomial model with power equation for its coefficients and a power model with quadratic polynomial coefficients predicted the maximum lateral deflection (ymax) and maximum penetration depth (zmax) variations with energy and magnetic field intensity, respectively. Conclusion: The applied correction for deflection angle will give more reliable results in initial energy of 250 MeV and 3T magnetic field intensity. For lower energies and magnetic field intensities the differences are negligible, clinicall