Objective To compare the performance of two different deep learning models,VTcGAN and Pix2pix,in generating synthetic computed tomography(sCT)from magnetic resonance imaging(MRI)of nasopharyngeal carcinoma(NPC),and to evaluate their accuracies in treatment planning dose calculations.Methods MRI and CT images as well as treatment planning data of 115 NPC patients were retrospectively selected,and paired dataset was obtained through rigid image registration,with 105 cases as the training set,and the remaining 10 cases as the test set.Two kinds of models,namely Pix2pix model based on conventional convolutional neural network and the improved VTcGAN model based on Transformer network,were constructed with the consistent structure except for the bottleneck network in the generator.The generated sCT images(sCTPix2pix and sCTVTcGAN)were assessed in terms of image quality,intensity value and dosimetric differences.Results For the cases in test set,the mean error,mean absolute error,peak signal-to-noise ratio,and structural similarity index between the ground truth CT images and the sCTPix2pix were(-0.86±12.42)HU,(40.77±3.06)HU,(33.45±0.62)dB,and 0.928±0.013,respectively;and those between the ground truth CT images and the sCTVTcGAN were(-1.10±8.56)HU,(37.40±2.08)HU,(34.33±0.45)dB,and 0.936±0.009,respectively.For the criterion of 1 mm/1%,the averaged gamma passing rates of sCTPix2pix and sCTVTcGAN were(96.62±1.08)%and(96.88±0.99)%at a dose threshold of 10%,(94.31±1.03)%and(94.72±0.91)%at a dose threshold of 50%,(84.62±1.74)%and(86.06±1.41)%at a dose threshold of 80%,respectively.Conclusion The proposed VTcGAN model is superior to the traditional Pix2pix model in terms of accuracy in generating sCT from MRI of NPC,and it can fulfill the requirements for dose calculation in the MRI-Only workflow.

Objective To compare the performance of two different deep learning models,VTcGAN and Pix2pix,in generating synthetic computed tomography(sCT)from magnetic resonance imaging(MRI)of nasopharyngeal carcinoma(NPC),and to evaluate their accuracies in treatment planning dose calculations.Methods MRI and CT images as well as treatment planning data of 115 NPC patients were retrospectively selected,and paired dataset was obtained through rigid image registration,with 105 cases as the training set,and the remaining 10 cases as the test set.Two kinds of models,namely Pix2pix model based on conventional convolutional neural network and the improved VTcGAN model based on Transformer network,were constructed with the consistent structure except for the bottleneck network in the generator.The generated sCT images(sCTPix2pix and sCTVTcGAN)were assessed in terms of image quality,intensity value and dosimetric differences.Results For the cases in test set,the mean error,mean absolute error,peak signal-to-noise ratio,and structural similarity index between the ground truth CT images and the sCTPix2pix were(-0.86±12.42)HU,(40.77±3.06)HU,(33.45±0.62)dB,and 0.928±0.013,respectively;and those between the ground truth CT images and the sCTVTcGAN were(-1.10±8.56)HU,(37.40±2.08)HU,(34.33±0.45)dB,and 0.936±0.009,respectively.For the criterion of 1 mm/1%,the averaged gamma passing rates of sCTPix2pix and sCTVTcGAN were(96.62±1.08)%and(96.88±0.99)%at a dose threshold of 10%,(94.31±1.03)%and(94.72±0.91)%at a dose threshold of 50%,(84.62±1.74)%and(86.06±1.41)%at a dose threshold of 80%,respectively.Conclusion The proposed VTcGAN model is superior to the traditional Pix2pix model in terms of accuracy in generating sCT from MRI of NPC,and it can fulfill the requirements for dose calculation in the MRI-Only workflow.

Objective:To explore the feasibility of applying ArcherQA to independent dose verification of MR-guided online adaptive radiotherapy (ART) plans performed on Elekta Unity 1.5 Tesla (T) magnetic resonance-linear accelerator (MR-Linac).Methods:The dose calculation accuracy of ArcherQA under a specific magnetic field was validated using a homogeneous water phantom. A total of 32 patients who received MR-guided online ART on Elekta Unity were randomly selected by lottery, with 32 offline plans and 177 online plans for five treatment sites (brain, mediastinum, liver, kidney, and vertebral body) enrolled. Finally, the γ pass rates (threshold: 10%; criteria: 3 mm/3% and 2 mm/2%) were compared among the result upon independent dose verification of ArcherQA, measurements of ArcCheck, and calculations using the Monaco treatment planning system (TPS) to quantitatively evaluate the accuracy and efficiency of ArcherQA in independent dose verification of online plans on Elekta Unity.Results:ArcherQA was proven accurate in calculating the dose distribution of therapeutic photon beams under the specific magnetic field. With the 3 mm/3% criterion, the γ pass rates of verification result exceeded 99% in all square fields of a water phantom. Under the stricter 2 mm/2% criterion, the γ pass rates also surpassed 95% in all square fields except 20 cm × 20 cm field. Regarding the verification of treatment plans, the ArcherQA result were found to be highly consistent with those measured or calculated using ArcCheck and Monaco TPS, with the average γ pass rates exceeding 99% under the 3 mm/3% criterion and above 97% under the 2 mm/2% criterion. ArcherQA was acceptably efficient for independent dose verification of online plans, with 50 to 150 s, (108 s on average) required to complete the independent dose verification of 177 online plans.Conclusions:ArcherQA allows for accurately and efficiently calculating the dose distribution of therapeutic photon beams under a specific magnetic field, establishing it as an effective supplementary tool for independent dose calculation of MR-guided offline and online ART plans, thereby ensuring the safety of patient treatment plans.

Objective:To explore the relationship between childhood trauma and anxiety in vocational school students, and to analyze the mediating role of emotion dysregulation.Methods:A cross-sectional survey was conducted in one vocational school in Ganzhou, all students completed a series of questionnaires, including the childhood trauma questionnaire (CTQ), difficulties in emotion regulation scale (DERS), and generalized anxiety disorder scale (GAD-7).The cut-off score for anxiety symptom was set GAD-7≥5.The data were analyzed using SPSS 23.0 and SPSS macro program PROCESS V4.0.Results:(1) The rate of anxiety in vocational school students was 42.96%, and girls were 27.1% higher than boys ( OR=1.271, 95% CI=1.095-1.474).(2) The CTQ (44(38, 51)) and DERS (98(89, 111)) in students with anxiety were both significantly higher than those in students without anxiety (39(34, 45), 81(73, 90), Z=-17.910, -33.859, both P<0.001).(3) Regression analysis showed that girls ( β=0.240, OR=1.271, 95% CI=1.095~1.474), childhood trauma ( β=0.028, OR=1.028, 95% CI=1.019~1.037), and emotion dysregulation ( β=0.076, OR=1.080, 95% CI=1.073-1.086) were significant predictors for anxiety.(4) Path analysis and mediating effect showed that childhood trauma positively predicted anxiety ( β=0.059, 95% CI=0.048-0.071) and emotion dysregulation ( β=0.802, 95% CI=0.749-0.854), and emotion dysregulation positively predicted anxiety ( β=0.139, 95% CI=0.132-0.145).Emotion dysregulation had a significant mediating effect (effect value=0.112, 95% CI=0.101-0.121) in the relationship between childhood trauma and anxiety, with the indirect effect accounting for 65.50% of the total effect. Conclusion:The incidence of anxiety symptoms is high among vocational school students, and childhood trauma not only directly affects anxiety symptoms, but also indirectly affects anxiety symptoms through emotion dysregulation.

Objective To investigate the surgical method and clinical outcome using the free anterolateral thigh flap with the medial gastrocnemius artery as the recipient artery for the repair of complex wounds in the lower leg. Methods A retrospective analysis was conducted on the clinical data of 11 patients with complex wounds in the lower leg admitted to Suzhou Ruihua Orthopedic Hospital from October 2020 to September 2022. All patients had extensive skin and subcutaneous soft tissue defects in the lower leg and received free anterolateral thigh flap repair with the medial gastrocnemius artery as the recipient artery. The skin of donor site was directly sutured. Results All 11 free skin flap survived in 11 patients, and both the donor and recipient sites healed in stage I. All patients were followed up after discharge, with a follow-up time of 12 to 35 months. The follow-up results at 12 months postoperatively showed good wound healing, good flap appearance and elasticity, restoration of normal knee and ankle joint function, and independent living ability. The donor site wounds healed well without significant scar hyperplasia. At the last follow-up, the flap sensory function was graded as S₃ in 2 patients and S₂ in 9 patients. The functional score of the affected limb was excellent in 5 patients and good in 6 patients, with an excellent and good rate of 100%. Conclusion The medial gastrocnemius artery has a suitable vessel caliber for anastomosis and a constant location. The use of the free anterolateral thigh flap with this artery as the recipient artery for the repair of severe wounds in the lower leg can effectively cover soft tissue defects and avoid injuring the residual main vessels in the lower leg, resulting in satisfactory outcomes.

Alzheimer's disease（AD） is an irreversible neurodegenerative disease with clinical manifestations such as memory impairment， aphasia， impaired visuospatial skills， executive function impairment， and personality changes. AD has brought a heavy burden to the family and society due to its unrevealed pathogenesis and the lack of therapeutic approaches. Saponins， a group of oligoglycosides whose aglycones are triterpenes or spirosteroids， are divided into triterpene saponins and steroidal saponins， which have a variety of biological activities. At present， there is no systematic review on the anti-AD effect of saponins. According to the literature published in recent years， the authors summarized the studies of saponins in improving AD based on animal experiments. The results indicated that saponins enhanced learning ability and improved cognitive impairment by inhibiting amyloid β-protein （Aβ） cascade activity， suppressing microtubule-associated protein （tau） hyperphosphorylation， inhibiting neuronal oxidative stress， inhibiting inflammatory factors， regulating apoptosis， inhibiting cholinergic neuronal degeneration， promoting mitochondrial autophagy， regulating intestinal flora， and enhancing energy metabolism， which in turn improved the pathological state of AD animal models. The therapeutic effects of different saponins on AD are different. The present study discussed the effect of different aglycones and sugar chains on the anti-AD activity based on saponins and anti-AD effect to provide new ideas and a theoretical basis for the development and utilization of saponins.

Objective:To explore the relationship between rumination and depression and suicide attempts, and the mediating effect of rumination between depression and suicide attempts in adolescents with depressive disorder.Methods:Clinical interviews and questionnaires were conducted on 331 adolescents aged 11-18 with depressive disorders.Depressive symptoms were assessed with patient health questionnaire-9 (PHQ-9). Rumination was assessed with ruminative responses scale-10 (RRS-10), and Chinese version of the sociality module of MINI5.0 was used to assess suicide.SPSS 23.0 software was applied to descriptive statistics, Chi-square test, t-test, Spearman correlation analysis and hierarchical regression analysis, and the SPSS macro program PROCESS V 3.4 was used for Bootstrap mediating effect. Results:The incidence of suicide attempts in adolescents with depressive disorder was 53.78%, which was significantly higher in girls (59.48%) than that in boys (40.40%), and the difference was significant ( χ2=10.16, P<0.01). In contrast to the non-suicide attempt group, suicide attempt group had higher scores on PHQ-9((11.08±9.26) vs (14.43±7.49), t=-3.634, P<0.01), brooding ((10.76±3.89) vs (12.44±3.87), t=-3.926, P<0.01), reflection ((10.05±3.54) vs (11.20±3.33), t=-3.044, P<0.01) and rumination total score ((20.81±6.78) vs (23.64±6.42), t=-3.898, P<0.01). Regression analysis revealed that girl ( β=0.175, t=3.228, P=0.001), depressive symptoms ( β=0.168, t=3.082, P=0.002), rumination ( β=0.138, t=2.364, P=0.019) were risk factors for suicide attempts.Rumination played a complete mediating effect between depressive symptoms and suicide attempts (effect value=0.013, 95% CI=0.003-0.027). Depression symptoms significantly and positively predicted rumination ( P<0.01), and rumination significantly and positively predicted suicide attempts ( P<0.05). Conclusion:The incidence of suicide attempts was high in adolescents with depressive disorders.Depressive symptoms affect suicide attempts mainly through rumination.Clinicians should assess the rumination of adolescents with depressive disorders.In addition, clinicians should implement concurrent psychotherapy to adjust the cognitive response and reduce rumination, in order to improve the mental health and reduce suicide attempts.

Objective:To analyze the dosimetric effects on off-center tumour treatment plan resulting from the MR-Linac-based isocenter position radiotherapy plan.Methods:The cases of 19 patients who were treated in Sun Yat-sen University Cancer Center in 2020 were collected in this study. Two different IMRT plans were designed for each patient with off-center tumor both for group A with planned isocenter position as IMRT and group B with planed target center position as geometric center. The conformity index and homogeneity index of target, the dose normal tissue and the number of MU were compared between two plans.Results:The two IMRT plans met clinical dosimetric requirements. No statistical differences were found both in homogeneity index and conformity index ( P>0.05). Also there was no differences found in doses to normal tissues. However, the MU number (1 149±903, t=2.804, P=0.012) in group A was higher than that in group B (970±652). Conclusions:It is feasible to perform MR-Linac-based off-center treatment plan.

Objective:To investigate the feasibilityof the adaptive radiotherapy using high-field MR-Linac systems for head neck cancers and perform the evaluation of target coverage and dose criteria.Methods:This study investigated 128 treatment plans of six patients who were treated on 1.5T MR-Linacsystems in Sun Yat-sen University Cancer Center in 2019, compared the differences in target coverage and dose criteria between the dose accumulation in the adaptive radiotherapy using MR-Linac systems and the reference plans, and evaluated the target coverage and dose criteria of each fraction of adaptive plan based on daily MRI anatomy.Results:There was no significant change in the target coverage and dose criteria for each treatment fraction(<1%). However, the change of lens dose was significant (maximum 98%). In addition, the result showed that there was no significant difference in target coverage and dose criteria between the dose accumulation in adaptive radiotherapy using MR-Linac systems and reference plans.In contrast, the average dose to lens was increased by 31.7%.Conclusions:It is feasible to perform adaptive radiotherapy using 1.5T MR-Linacsystems for head neck cancers according tothe evaluation of target coverage and dose criteria. Additionally, since the actual dose tolens was quite different from the reference plan, the lens exposure should be considered in clinical practice.

Objective:To investigate the impacts of electron streaming effect (ESE) on out-of-field dose distribution in 1.5 T MRI-guided radiotherapy.Methods:Firstly, the Monaco v5.40.1 (Elekta AB, Stockholm, Sweden) treatment planning system (TPS) was implemented to investigate the ESE in a square field (5 cm × 5 cm) at the entry and exit sides of a special homogeneous water phantom. Afterward, a retrospective investigation was conducted into one laryngeal cancer case and one breast cancer case who had been treated on a conventional linear particle accelerator (linac). Then doses were recalculated in the Monaco system using a Unity machine model. Meanwhile, the out-of-field skin dose enhancement induced by ESE was investigated.Results:ESE-induced dose variations were observed at both the entry and exit sides of the phantom surface in the presence of a magnetic field, with the ESE on the exit side notably stronger than that on the entry side. For the laryngeal cancer case, the ESE was not notable and had insignificant impacts on the out-of-field skin dose. In contrast, ESE-induced in-air high-dose region outside the body stretched to the chin area for the breast cancer case. This led to the skin dose escalation of the chin at D1 cm 3 454.6 cGy. After the application of 1 cm bolus, the corresponding skin dose of the chin D1 cm 3 reduced to as low as 113.6 cGy, which is almost equivalent to that in the absence of a magnetic field ( D1 cm 3=92.5 cGy). Conclusions:The ESE in a magnetic field can alter out-of-field dose and lead to local dose enhancement along the electron path. Although the ESE had insignificant impacts on the out-of-field dose of the laryngeal cancer case, it reached the chin area of the breast cancer case. ESE can be effectively shielded by adding protective bolus.