ABSTRACT
Objective:To explore the rapid evaluation of the early pathogen of severe Chlamydophila psittaci pneumonia by bedside diagnostic bronchoscopy, so as to start effective anti-infection treatment before the results of macrogenome next generation sequencing (mNGS) test. Methods:The clinical data of three patients with severe Chlamydophila psittaci pneumonia who were successfully treated in the First Affiliated Hospital of Xinjiang Medical University, the First People's Hospital of Aksu District, and the First Division Hospital of Xinjiang Production and Construction Corps from October 2020 to June 2021 were retrospectively analyzed, including the rapid assessment of early pathogens by bedside diagnostic bronchoscopy and the use of antibiotics to start anti-infection treatment. These patients were successfully treated. Results:The three patients were male, aged 63, 45 and 58 years old, respectively. Before the onset of the penumonia, they had a clear medical history of bird exposure. The clinical manifestations mainly included fever, dry cough, shortness of breath and dyspnea. One case had abdominal pain and lethargy. The results of laboratory examination indicated that the peripheral blood white blood cell count (WBC) of two patients were high [(10.2-11.9)×10 9/L], the percentage of neutrophils increased (85.2%-94.6%) and the percentage of lymphocytes decreased (3.2%-7.7%) in all 3 patients after admission to hospital and entering into intensive care unit (ICU). The procalcitonin (PCT) of 3 patients increased after admission, and still increased when entering ICU (0.3-4.8 ng/L), so did C-reactive protein (CRP, 58.0-162.0 mg/L) and erythrocyte sedimentation rate (ESR, 36.0-90.0 mm/1 h). After admission, serum alanine transaminase (ALT) increased in 2 cases (136.7 U/L, 220.5 U/L), so did aspartate transaminase (AST) in 2 cases (249.6 U/L, 164.2 U/L). ALT (162.2-267.9 U/L) and AST (189.8-223.2 U/L) increased in 3 patients when they entered ICU. The level of serum creatinine (SCr) of 3 patients were normal after admission and entering ICU. The chest computed tomography (CT) findings of 3 patients were acute interstitial pneumonia, bronchopneumonia and lung consolidation, of which 2 cases were accompanied by a small amount of pleural effusion, and 1 case was accompanied by more regular small air sacs. Multiple lung lobes were involved, but mainly one lung lobe. The oxygenation index (PaO 2/FiO 2) of the 3 patients admitting to ICU were 100.0, 57.5 and 105.4 mmHg (1 mmHg ≈ 0.133 kPa), respectively, which met with the diagnostic criteria of moderate and severe acute respiratory distress syndrome (ARDS). All three patients received endotracheal intubation and mechanical ventilation. Under the bedside bronchoscope, the bronchial mucosa of 3 patients were obviously congested and edematous, without purulent secretion, and there was 1 case with mucosal hemorrhage. Three patients underwent bedside diagnostic bronchoscopy, and the evaluation result of the pathogen was that it might be atypical pathogen infection, so they were given moxifloxacin, cisromet and doxycycline intravenously, respectively, and combined with carbapenem antibiotics intravenously. After 3 days, the detection results of mNGS in bronchoalveolar lavage fluid (BALF) showed that only Chlamydia psittaci was infected. At this time, the condition was significantly improved, and PaO 2/FiO 2 was significantly increased. Therefore, the antibiotic treatment scheme remained unchanged, and mNGS only served to verify the initial diagnosis. Two patients were extubated on the 7th and 12th day of admission to the ICU, respectively, while one patient was extubated on the 16th day of admission to the ICU due to nosocomial infection. All 3 patients were transferred to the respiratory ward after the condition was stable. Conclusion:The bedside diagnostic bronchoscopy based on clinical characteristics is conducive to not only the rapid assessment of the early pathogens of severe Chlamydia psittaci pneumonia, but also effective anti-infection treatment before the returning of mNGS test results, which can make up for the lag and uncertainty of the mNGS test results.
ABSTRACT
Objective:To analyze the influence of magnetic field on the proton beam delivery and dose distribution, and develop a correction method for the Bragg peak (BP) shift under the vertical magnetic field, providing reference for the dose calculation and beam delivery of MRI-guided proton therapy.Methods:Monte Carlo (MC) simulation was used to study the dose distribution of the proton beam in the water phantom under the magnetic field. The BP location was corrected by the method of" angle correction+ energy correction" , and the correction parameters were calculated by the analytical formula based on the simulation data.Results:The magnetic field caused the dose distortion and shift of BP location. The shift degree was increased with the increase of field strength and initial energy. Compared with MC simulation, the result of calculating proton deflection in the air by the analytical method yielded a deviation within 0.2%. Based on the simulation data and calculation formulas, the correction parameters under different conditions could be calculated within 1 s by using the MATLAB programming. The calculation results showed that the air layer with magnetic field, isocenter depth, irradiation direction exerted different influence on the correction parameters. After correction, the BP location was basically consistent with the expected (offset ≤0.2 mm).Conclusions:The BP shift under the vertical magnetic field can be effectively corrected by " the angle correction+ energy correction" method. The correction parameters under different conditions can be quickly and accurately calculated by the calculation formulas based on simulation data.
ABSTRACT
Objective:To develop and validate the accuracy of an independent dose calculation toolkit for the horizontal beamline of Shanghai Advanced Proton Therapy (SAPT) facility based on an open-source dose calculation engine.Methods:Machine data, such as absolute integral depth doses (IDDs) and lateral profiles in air were measured and lateral profiles in water were derived by Monte-Carlo simulations. The dose computation models for SAPT horizontal beamline pencil beams in water were achieved by combining machine data and dose calculation engine. The verification of the dose reconstruction toolkit included absolute dose verification and relative dose verification. The absolute dose verification is performed to mainly compare the reconstructed value and the measured value at different depths along the center axis of the beam direction of a cube plan. The relative dose verification is conducted to mainly compare the lateral profile or two-dimensional dose distribution between the measured value and the reconstructed value. Meanwhile, the precision of double-gaussian and single-gaussian lateral beam models was compared.Results:The deviations of the absolute dose between the calculated and measured values were basically within 2%. The deviations of 20%-80% penumbra between the measured and the calculated values were within 1 mm, and deviations of the full width at half height were within 2 mm. For 3 cube plans and 2 clinical cases, the two-dimensional gamma pass rates (3 mm/3%) between the measured and calculated dose distributions at the corresponding depths were greater than 95%. The double-gaussian lateral beam model was more accurate in the high dose gradient region and deeper depth.Conclusion:The precision of independent dose calculation toolkit is acceptable for clinical requirements, which can be employed to investigate other dose-related issues.