Comprehensive Treatment Uncertainty Analysis and PTV Margin Estimation for Fiducial Tracking in Robotic Liver Stereotactic Body Radiation Therapy

Objective This study aims to quantify the uncertainties of CyberKnife Synchrony fiducial tracking for liver stereotactic body radiation therapy(SBRT)cases,and evaluate the required planning target volume(PTV)margins.Methods A total of 11 liver tumor patients with a total of 57 fractions,who underwent SBRT with synchronous fiducial tracking,were enrolled for the present study.The correlation/prediction model error,geometric error,and beam targeting error were quantified to determine the patient-level and fraction-level individual composite treatment uncertainties.The composite uncertainties and multiple margin recipes were compared for scenarios with and without rotation correction during treatment.Results The correlation model error-related uncertainty was 4.3±1.8,1.4±0.5 and 1.8±0.7 mm in the superior-inferior(SI),left-right,and anterior-posterior directions,respectively.These were the primary contributors among all uncertainty sources.The geometric error significantly increased for treatments without rotation correction.The fraction-level composite uncertainties had a long tail distribution.Furthermore,the generally used 5-mm isotropic margin covered all uncertainties in the left-right and anterior-posterior directions,and only 75%of uncertainties in the SI direction.In order to cover 90%of uncertainties in the SI direction,an 8-mm margin would be needed.For scenarios without rotation correction,additional safety margins should be added,especially in the superior-inferior and anterior-posterior directions.Conclusion The present study revealed that the correlation model error contributes to most of the uncertainties in the results.Most patients/fractions can be covered by a 5-mm margin.Patients with large treatment uncertainties might need a patient-specific margin.

The effect of plasma uric acid on oxidative stress in ankylosing spondylitis by Keap1-Nrf2 signaling pathway

Objective:To investigate the mechanism of serum uric acid in Ankylosing spondylitis(AS)through the Kelch-like ECH-Associating protein 1(Keap1)-nuclear factor erythroid 2 related factor 2(Nrf2)signaling pathway.Methods:A total of 60 AS patients in our hospital from March 2018 to October 2019 were recruited and divided into the active group(>4 points,26 cases)and the inactive group(≤4 points,34 cases)according to the Bath Ankylosing Spondylitis Disease Activity Index(BASDAI).Keap1,Nrf2,catalase(CAT),superoxide dismutase(SOD),Malondialdehyde(MDA),reactive nitrogen species(RNS),reactive oxygen species(ROS)were detected by ELISA;furthermore,erythrocyte sedimentation rate(ESR),Uric acid(UA)and C-reactive protein(CRP)were tested.The relationship among UA,BASDAI and oxidative stress indicators were analyzed.Results:The expression levels of ESR,CRP,UA,ROS,RNS,MDA,and Keap1 in the active group were significantly higher than those in the inactive group(all P<0.001);the levels of Nrf2,CAT,and SOD in the active group were higher than those in the inactive group,markedly reduced(all P<0.001)in the inactive group.The Pearson's correlation coefficient showed that ROS,RNS,MDA,and Keap1 were notably positively correlated with blood UA and BASDAI in the active group with AS patients;while Nrf2,CAT,and SOD were negatively correlated with blood UA and BASDAI.Moreover,blood UA and BASDAI were found to be moderately positively correlated.Conclusion:The results in the study demonstrate that the UA level in blood is related to the AS disease activity,blood UA exerts the pro-inflammatory effects,increasing oxidative stress injury and reducing antioxidant capacity,possibly by activating the Keap1-Nrf2 pathway.

Anti-inflammatory effect of luteolin in acute gouty arthritis rat model

Objective: To explore the anti-inflammatory effect of luteolin on rats with acute gout arthritis. Methods: A total of forty-eight rats were chosen and randomly divided into six groups. The acute gout arthritis model of rats was established by injecting monosodium urate at the concentration of 25 mg/mL into the ankle joint cavity. Changes of joint swelling index at different time points and the levels of IL-1β, IL-17, TNF-α, IL-6 in serum and synovial were measured. Results: Compared with the control group, the swelling index of ankle joint and gait score in the model group was significantly enhanced at different time points (all P<0.01). Compared with the MSU group, luteolin improved the ankle swelling index of rats with acute gout arthritis (P<0.05), and significantly down-regulated the levels of IL-1β, IL-17, TNF-α, IL-6 (P<0.01). Conclusion: Luteolin can alleviate the inflammatory response of acute gouty arthritis and may be an effective drug for acute gouty arthritis.