Objective To propose and validate a decomposition method based on half-projection reconstruction for dual-energy cone beam CT(DE CBCT),thereby providing a potentially feasible low-dose imaging solution for anatomical monitoring and dose reconstruction optimization in adaptive radiotherapy.Methods Dual-energy scans were performed on a Gammex phantom using the on-board kilovoltage CBCT system of a VitalBeam accelerator at acquisition frame rates of 15 and 7 frames per second(f/s).Images were reconstructed from the projection data,and dual-energy decomposition was applied to the 7 f/s dual-energy images to derive relative electron density(RED)and stopping power ratio(SPR)using weighted formulas and empirical functions,followed by accuracy evaluation.Additionally,the weighted CT dose index was calculated for different scanning parameters.Results Dual-energy decomposition effectively suppressed image artifacts,with RED and SPR errors remaining below 2.82%and 2.56%,respectively.Compared with the traditional dual-scan method which required high-and low-energy acquisitions,the weighted CT dose index of the half-projection DE CBCT was reduced by 11.60 mGy(a 52.90%reduction).Furthermore,it was 2.58 mGy lower than the dose of the full-projection high-energy CBCT alone(a 19.98%reduction)and only 1.31 mGy higher than that of the low-energy CBCT(a 14.52%increase).Conclusion The proposed method effectively suppresses image artifacts while maintaining high accuracy in RED and SPR under low radiation dose conditions,demonstrating its potential value for scenarios requiring frequent image guidance,such as adaptive radiotherapy.

Objective To propose and validate a decomposition method based on half-projection reconstruction for dual-energy cone beam CT(DE CBCT),thereby providing a potentially feasible low-dose imaging solution for anatomical monitoring and dose reconstruction optimization in adaptive radiotherapy.Methods Dual-energy scans were performed on a Gammex phantom using the on-board kilovoltage CBCT system of a VitalBeam accelerator at acquisition frame rates of 15 and 7 frames per second(f/s).Images were reconstructed from the projection data,and dual-energy decomposition was applied to the 7 f/s dual-energy images to derive relative electron density(RED)and stopping power ratio(SPR)using weighted formulas and empirical functions,followed by accuracy evaluation.Additionally,the weighted CT dose index was calculated for different scanning parameters.Results Dual-energy decomposition effectively suppressed image artifacts,with RED and SPR errors remaining below 2.82%and 2.56%,respectively.Compared with the traditional dual-scan method which required high-and low-energy acquisitions,the weighted CT dose index of the half-projection DE CBCT was reduced by 11.60 mGy(a 52.90%reduction).Furthermore,it was 2.58 mGy lower than the dose of the full-projection high-energy CBCT alone(a 19.98%reduction)and only 1.31 mGy higher than that of the low-energy CBCT(a 14.52%increase).Conclusion The proposed method effectively suppresses image artifacts while maintaining high accuracy in RED and SPR under low radiation dose conditions,demonstrating its potential value for scenarios requiring frequent image guidance,such as adaptive radiotherapy.

Objective To acquire the external contour changes and positioning errors during fractionated intensity-modulated radiotherapy for nasopharyngeal carcinoma using kilovoltage cone-beam computed tomography(CBCT),and to analyze their effects on the dose distributions in target areas and organs-at-risk.Methods Twenty-one patients with nasopharyngeal carcinoma were enrolled in the study,and the positioning errors in the left-right,superior-inferior and anterior-posterior directions were obtained by matching 137 CBCT images with the positioning CT images.The transverse width of the external contour was measured at 3 different layers of the neck,and its effects on positioning errors were analyzed using Pearson's coefficient and independent sample t-tests.Additionally,simulation plans based on CBCT images were created to analyze the effects of positioning errors and external contour changes on radiotherapy dose,with Mann-Whitney U tests applied for significance analysis.Results The positioning errors in the left-right,superior-inferior and anterior-posterior directions were(1.04±0.73),(1.13±0.87)and(1.38±0.95)mm,respectively.The rates of external contour changes at the A,B and C layers of the head and neck were 15.36%,14.94%and 14.99%,respectively.Compared with executed plans,simulation plans had lower GTV D98,CTV1 D95 and CTV2 D95(P<0.05),and higher Dmax for the brainstem and spinal cord(P<0.05).Conclusion The simulation plans indicate that the presence of uncertainties such as positioning errors and external contour changes will significantly affect dose distributions in target areas,with the largest decrease observed in GTV D98(11.49%)and the maximum change rates in CTV1 D95 and CTV2 D95 being 12.88%and 21.64%,respectively.Except for the left and right lenses and left parotid gland,significant differences are observed in the doses for the other organs-at-risk and target areas,suggesting that positioning errors and external contour changes in actual radiotherapy will exert significant effects on dose distributions.

The pathophysiological process of immune inflammatory response after severe trauma is extremely complex, especially manifested in the dynamic changes. In the physiological response state, the inflammatory and anti-inflammatory conditions are in a dynamic balance. The immune inflammatory response is relatively stable, avoiding excessive inflammatory reactions or immunosuppression and reducing further damage to the body. In the pathological response state, the dynamic balance between inflammatory and anti-inflammatory is broken, and it can also lead to persistent inflammatory-immunosuppression-catabolism syndrome (PICS). As a result, it increases serious complications such as uncontrolled inflammatory reactions, sepsis, multiple organ dysfunction syndrome (MODS), and multiple organ failure (MOF). Current researches on post-traumatic immune inflammatory response have also expanded to the genetic level, indicating that the over-expression of genes and the generation and increase of immune response media are likely to be the key reasons for the disorder of immune inflammatory response. The author reviews the research progress of immune inflammatory response mechanism and related clinical intervention after severe trauma, in order to summarize the previous research results and explore the future research direction.

Objective To study the influence of elicitors on growth and baicalin biosynthesis in hairy root of Scutellaria baicalensis(HRSB).Methods The elicitors from the solution of Ca2+,Mg2+,Co2+ and fungal elicitors extracted from Aspergillus niger,A.oryzae,and Armillaria mellea were cocultivated with HRSB and the content of baicalin was determined by HPLC.Results Every elicitor has different influences on the growth and baicalin biosynthesis.When the concentration of A.niger was 40 mg/L,A.oryzae was 20 mg/L,and the Co2+ is 1.53?10-4 mmol/L,the content of baicalin increased respectively to 9.18%,8.81%,and 8.62%.Conclusion Elicitors could improve some specific secondary metabolic synthesis.The test implies that the elicitors of A.niger,A.oryzae,and Co2+ could effectively improve the synthesis of baicalin.