The clinical data from 16 patients who underwent surgery for acute type A aortic dissection under ultra-fast-track anesthesia (UFTA) in the Second Affiliated Hospital of Nanjing Medical University from August 2023 to December 2023 were collected, and the experience of anesthesia management was analyzed and summarized. UFTA strategy was to reduce inflammation and perform multi-organ protection in the perioperative period through cardiopulmonary bypass methods, medications, etc. According to the process of operation, the long-term and short-acting anesthetic drugs were accurately used to achieve the patient′s awakening immediately after the operation. Deep anesthesia extubation, remifentanil infusion techniques, and nasal high-flow ventilation were used to enable patients to be removed from the endotracheal tube with low stress under the premise of safety. All the patients successfully completed anesthesia induction and anesthesia maintenance. The average surgery duration was (413±92) min, the average anesthesia duration was (480±100) min, the cardiopulmonary bypass time was (168±42) min, the cardiac arrest time was (119±36) min, and the deep hypothermic circulatory arrest lasted (24±5) min. Of these patients, 14 underwent deep hypothermic circulatory arrest combined with unilateral cerebral perfusion via the right axillary artery, and 2 underwent deep hypothermic circulatory arrest combined with retrograde cerebral perfusion via the superior vena cava. All the patients had their tracheal tubes removed within 30 min postoperatively, with blood gas analysis and hemodynamics being within or close to normal ranges. The average postoperative intensive care unit stay time was 6 (3, 11) days, and the total length of hospital stay was (23±8) days. The total hospitalization time extended 20 days in 7 patients due to postoperative complications. All the patients recovered and were discharged. In conclusion, the application of UFTA strategy is safe and feasible in the patients with acute type A aortic dissection, allowing for immediate extubation in the operating room.

Objective:To investigate the role of apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) in ferroptosis of mouse dendritic cells (DCs) under simulated sepsis, providing evidence for improving immunosuppression in sepsis caused by wound infection.Methods:This study was an experimental research. The mouse DC line DC2.4 in the logarithmic growth phase (with passages 3-10) was used for the experiments (with each sample size of 3). The sepsis model was established by treating DCs with 1 μg/mL lipopolysaccharide (LPS, same concentration throughout) for 0 (untreated), 6, 12, 24, 48, and 72 h. Western blotting was used to detect the protein expressions of APE1 and anti-ferroptosis proteins glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) in cells, flow cytometry was employed to detect reactive oxygen species (ROS) levels in cells, and live-cell imaging technology was used to measure cell lipid peroxidation levels. DCs successfully transfected with lentivirus containing APE1 short hairpin RNA sequence were divided into APE1-knockdown+phosphate buffer solution (PBS) group and APE1-knockdown+LPS group. DCs successfully transfected with empty lentivirus were divided into empty vector+PBS group and empty vector+LPS group. After stimulation with PBS or LPS and 24 h of culture, corresponding assays were conducted as above. DCs transfected with lentivirus containing APE1 overexpression RNA sequence were divided into APE1-overexpression+PBS group and APE1-overexpression+LPS group. DCs transfected with empty lentivirus were divided into empty vector+PBS group and empty vector+LPS group. After stimulation with PBS or LPS and 24 h of culture, corresponding assays were conducted as above. A total of 88 male C57BL/6J mice aged 6-8 weeks were divided into corn oil+sham injury group, corn oil+cecal ligation and puncture (CLP) group, inhibitor+sham injury group, and inhibitor+CLP group ( n=22) according to the random number table. Mice in the two inhibitor groups were gavaged with APE1 inhibitor E3330 (1 mg/mL in concentration) at 40 mg/kg per day, while mice in the two corn oil groups were gavaged with an equal amount of corn oil daily. Two weeks later, mice in the two CLP groups underwent CLP surgery to establish a sepsis model, while mice in the two sham injury groups underwent sham injury. Sixteen mice from each group were selected to observe survival within 7 d post-surgery. At 24 h post-surgery, CD11c-positive magnetic beads were used to extract spleen DCs from the remaining six mice in each group for corresponding assays ( n=3) as above. Results:Compared with that of LPS treatment at 0 h, APE1 protein expression significantly increased in cells at 6 h of LPS treatment ( P<0.05), APE1 and GPX4 protein expressions significantly decreased at 24, 48, and 72 h of LPS treatment, SLC7A11 protein expression significantly decreased at 24 h of LPS treatment ( P<0.05), while the ROS level in cells ( P<0.05) and cell lipid peroxidation level significantly increased at 24, 48, and 72 h of LPS treatment. After 24 h of culture, the GPX4 protein expression of cells in APE1-knockdown+LPS group was significantly lower than that in APE1-knockdown+PBS group ( P<0.05), while the ROS level in cells ( P<0.05) and cell lipid peroxidation level were significantly higher than those in APE1-knockdown+PBS group and empty vector+LPS group. After 24 h of culture, APE1, SLC7A11, and GPX4 protein expressions of cells in APE1-overexpression+LPS group were significantly higher than those in empty vector+LPS group ( P<0.05), while the ROS level in cells ( P<0.05) and cell lipid peroxidation level were significantly lower than those in empty vector+LPS group. At 24 h post-surgery, APE1 and GPX4 protein expressions of mice cells in inhibitor+CLP group were significantly lower than those in inhibitor+sham injury group and corn oil+CLP group ( P<0.05); the ROS level of mice cells in corn oil+CLP group (12 693±913) was significantly higher than that in corn oil+sham injury group (4 205±805, P<0.05), while the ROS level of mice cells in inhibitor+CLP group (18 085±223) was significantly higher than that in inhibitor+sham injury group (4 381±787) and corn oil+CLP group (with P values all <0.05); the cell lipid peroxidation level of mice in inhibitor+CLP group was significantly higher than that in inhibitor+sham injury group and corn oil+CLP group. Within 7 d post-surgery, the survival ratio of mice in inhibitor+CLP group was significantly lower than that in inhibitor+sham injury group ( χ2=22.67, P<0.05). Conclusions:Under simulated sepsis, the APE1 expression in mouse DCs is decreased, and oxidative stress and ferroptosis are enhanced; knocking down the APE1 exacerbates DC ferroptosis, while APE1 overexpression effectively reduces DC ferroptosis. The inhibition of APE1 expression in DCs is closely associated with poor prognosis in sepsis.

Objective:To investigate the effects of stimulator of interferon gene (STING) on ferroptosis mediated by acyl-CoA synthetase long-chain family member 4 (ACSL4) in mouse dendritic cells (DCs) under sepsis, providing a basis for improving the dysregulation of immune response in sepsis caused by factors such as wound infection.Methods:This study was an experimental research. The mouse DC line DC2.4 in the logarithmic growth phase (with passages 3-10) were divided into lipopolysaccharide (LPS) stimulation 0 h (unstimulated) group, LPS stimulation 6 h group, LPS stimulation 12 h group, LPS stimulation 18 h group, and LPS stimulation 24 h group according to the random number table (the same grouping method below), which were cultured with 1 μg/mL LPS (the same concentration below) for the corresponding time. The protein expressions of phosphorylated STING (p-STING), STING, and ACSL4 in cells were determined by Western blotting. DC2.4 successfully transfected with lentivirus containing STING gene small interfering RNA (hereinafter referred to as siSTING) were divided into siSTING+phosphate buffer solution (PBS) group and siSTING+LPS group. DC2.4 successfully transfected with empty lentivirus were divided into empty vector+PBS group and empty vector+LPS group. After being stimulated with PBS or LPS and cultured for 24 hours, the protein expressions of p-STING, STING, and ACSL4 in cells were determined as above. Cell lipid peroxidation degrees were observed using the lipid peroxidation assay kit, and cell apoptosis rates were detected using flow cytometry. The sample numbers in the above cell experiments were all 3. Eighty male C57BL/6J mice aged 6 to 8 weeks were divided into sham surgery+normal saline (NS) group, cecal ligation and puncture (CLP)+NS group, sham surgery+C-176 group, and CLP+C-176 group, with 20 mice in each group. Mice in the two C-176 groups were intraperitoneally injected with C-176, while mice in the two NS groups were intraperitoneally injected with an equivalent volume of NS. One hour later, sham surgery was performed on the mice in the two sham surgery groups, and CLP surgery was performed on the mice in the two CLP groups to establish a sepsis model. At 24 h post-surgery, 10 mice from each group were sacrificed to extract spleen DCs, and protein expression, lipid peroxidation, and apoptosis rates were detected as above ( n=3). Hematoxylin-eosin staining was performed to observe pathological damage in the heart, liver, lung, and kidney tissue. The remaining 10 mice in each group were observed for survival within 7 days after surgery. Results:The protein expressions of p-STING, STING, and ACSL4, as well as the p-STING/STING ratio in DC2.4 in LPS stimulation 24 h group were significantly higher than those in LPS stimulation 0 h group ( P<0.05). After 24 h of culture, the protein expressions of p-STING, STING, and ACSL4 in DC2.4 in siSTING+LPS group and empty vector+PBS group were significantly lower than those in empty vector+LPS group ( P<0.05); the lipid peroxidation degrees of DC2.4 in siSTING+LPS group and empty vector+PBS group were weaker than those in empty vector+LPS group. The apoptosis rates of DC2.4 in empty vector+PBS group, empty vector+LPS group, siSTING+PBS group, and siSTING+LPS group were (15.7±3.0)%, (37.8±2.9)%, (13.1±2.1)%, and (20.6±1.8)%, respectively. The apoptosis rates of DC2.4 in empty vector+PBS group and siSTING+LPS group were significantly lower than that in empty vector+LPS group ( P<0.05). At 24 h post-surgery, the protein expressions of p-STING and ACSL4, and the p-STING/STING ratio in spleen DCs of mice in CLP+NS group were significantly higher than those in sham surgery+NS group and CLP+C-176 group ( P<0.05); the protein expression of STING in spleen DCs of mice in CLP+NS group was significantly higher than that in sham surgery+NS group ( P<0.05); the lipid peroxidation degrees of spleen DCs of mice in CLP+C-176 group and sham surgery+NS group were weaker than that in CLP+NS group. The apoptosis rates of spleen DCs of mice in sham surgery+NS group and CLP+C-176 group were significantly lower than that in CLP+NS group ( P<0.05), and the apoptosis rate of spleen DCs of mice in CLP+C-176 group was significantly higher than that in sham surgery+C-176 group ( P<0.05). Pathological tissue damage in the heart, liver, lung, and kidney of mice in CLP+NS group was significantly worse than that in sham surgery+NS group, while such damage in the above organs of mice in CLP+C-176 group was significantly alleviated compared with that in CLP+NS group. The survival ratio of mice in CLP+NS group within 7 days after surgery was significantly lower than that in sham surgery+NS group ( χ2=8.30, P<0.05). Conclusions:Under sepsis, STING activation in mouse DCs is significant, which enhances ACSL4-mediated ferroptosis. Inhibiting STING activation can significantly reduce ACSL4-mediated ferroptosis level in mouse DCs under sepsis, thereby improving the survival rate of septic mice.

Objective To predict whether antiviral therapy is required in patients with chronic hepatitis B virus(HBV)infection and an age of≤30 years by establishing a noninvasive model,and to investigate the diagnostic value of this model.Methods A retrospective analysis was performed for the clinical data of 175 patients with chronic HBV infection who were admitted to Shenzhen Third People's Hospital from January 2017 to January 2023 and met the inclusion criteria,and according to the results of liver biopsy,they were divided into treatment group with 41 patients(with indications for antiviral therapy)and observation group with 134 patients(without indications for antiviral therapy).The two groups were analyzed in terms of the indicators including clinical data,imaging examinations,and serum biochemical parameters.The univariate and multivariate Logistic regression analyses were used to investigate the parameters affecting the indication for antiviral therapy,and different models for predicting the need for antiviral therapy were constructed based on related parameters.The receiver operating characteristic(ROC)curve was used to compare the diagnostic value of different models.The independent-samples t test was used for comparison of normally distributed continuous variables between groups,and the Mann-Whitney U rank sum test was used for comparison of non-normally distributed continuous variables between groups;the chi-square test or the Fisher's exact test was used for comparison of categorical data between groups.Results There were significant differences between the treatment group and the observation group in alanine aminotransferase,ferritin,total cholesterol(CHOL),triglyceride,platelet count,liver stiffness measured by sound touch elastography(STE),and procollagen Ⅲ N-terminal propeptide(PIIIP)(all P<0.05).The multivariate Logistic regression analysis showed that CHOL(odds ratio[OR]=0.4,95％confidence interval[CI]:0.2—1.0),STE(OR=1.5,95％CI:1.0—2.1),and PIIIP(OR=1.1,95％CI:1.0—1.1)were independent predictive factors for the indications for antiviral therapy.Model 1(STE+PIIIP+CHOL),model 2(STE+PIIIP),model 3(STE+CHOL),model 4(PIIIP+CHOL)had an area under the ROC curve of 0.908,0.848,0.725,and 0.725,respectively,while STE,PIIIP,and CHOL used alone had an AUC of 0.836,0.725,and 0.634,respectively,suggesting that model 1 had the largest AUC,with a specificity of 77.34％and a sensitivity of 96.36％,and had a significant difference compared with STE,PIIIP,CHOL,and the models 2,3,and 4(Z=0.21,3.08,3.06,3.23,0.89,and 0.88,all P<0.05).Conclusion The noninvasive model established based on CHOL,STE,and PIIIP has a good value in predicting the need for antiviral therapy in patients with chronic HBV infection and an age of≤30 years.

Objective To explore the safety and efficacy of neoadjuvant chemotherapy(NAC)combined with immunotherapy before radical cystectomy plus pelvic lymph nodes dissection(RC-PLND)for muscle-invasive bladder cancer(MIBC).Methods The clinical data of 101 patients with MIBC who underwent neoadjuvant therapy followed by RC-PLND in the Department of Urology,the First Affiliated Hospital of Xi'an Jiaotong University during Jan.2019 and Dec.2023 were retrospectively analyzed,including 71 patients(70.3％)who received NAC(NAC group)and 30(29.7％)who received NAC combined with immunotherapy(NAC combine immunotherapy group).The clinical and pathological data and adverse events during neoadjuvant therapy were compared.Logistic regression analysis was used to explore the independent predictors of pathological complete response(pCR)and pathological partial response(pPR).Results There were no significant differences in the baseline data between the two groups(P＞0.05).However,the proportion of multiple tumors in patients receiving NAC before surgery was significantly higher than that in the NAC combined immunotherapy group(69.0％vs.46.7％,P=0.034).Compared with NAC group,NAC combined with immunotherapy group had significantly improved rate of pathological downstaging and pPR(60.6％vs.83.3％,P=0.026;45.1％vs.70.0％,P=0.022).Furthermore,the rate of pCR in patients undergoing NAC combined immunotherapy was higher than those undergoing NAC,but the difference was not significant(53.3％vs.33.8％,P=0.067).Logistic regression analysis revealed that clinical T-stage and tumor diameter were independent predictors of pCR and pPR(P＜0.05).In addition,the most common adverse events during neoadjuvant therapy were anemia,decreased white blood cells,nausea,and vomiting,but most of them were grade 1-2 and could be relieved through symptomatic treatment.Conclusion NAC combined with immunotherapy is safe and effective,which can improve the rate of pathological downstaging,pPR and pCR,without increasing the incidence of adverse reactions.

Objective:To investigate the clinical efficacy of redo rectal resection and coloanal anastomosis.Methods:The retrospective and descriptive study was conducted. The clinicopatholo-gical data of 49 patients who underwent redo rectal resection and coloanal anastomosis for the treatment of local recurrence of tumors and failure of colorectal or coloanal anastomosis after rectal resection in the Sixth Affiliated Hospital of Sun Yat-sen University from November 2012 to December 2021 were collected. There were 32 males and 17 females, aged 57(range,31-87)years. Redo rectal resection and coloanal anastomosis was performed according to the patient′s situations. Observa-tion indicators: (1) surgical situations; (2) postoperative situations; (3) follow-up. Measurement data with normal distribution were represented as Mean± SD, and measurement data with skewed distri-bution were represented as M( Q1, Q3) or M(range). Count data were described as absolute numbers or percentages. Results:(1) Surgical situations. All 49 patients underwent redo rectal resection and coloanal anastomosis successfully, with the interval between the initial surgery and the reopera-tion as 14.2(7.1,24.3)months. The operation time and volume of intraoperative bold loss of 49 patients in the redo rectal resection and coloanal anastomosis was 313(251,398)minutes and 125(50,400)mL, respectively. Of the 49 patients, there were 38 cases receiving laparoscopic surgery including 12 cases with transanoscopic laparoscopic assisted surgery, 11 cases receiving open surgery including 2 cases as conversion to open surgery, there were 20 cases undergoing Bacon surgery, 14 cases undergoing Dixon surgery, 12 cases undergoing Parks surgery, 2 cases undergoing intersphincter resection and 1 case undergoing Kraske surgery, there were 20 cases undergoing rectum dragging out excision and secondary colonic anastomosis, 13 cases undergoing dragging out excision single anastomosis, 12 cases undergoing rectum dragging out excision double anastomosis, 4 cases undergoing first-stage manual anastomosis, there were 21 cases with enterostomy before surgery, 16 cases with prophylactic enterostomy after surgery, 12 cases without prophylactic enterostomy after surgery. The duration of postoperative hospital stay of 49 patients was (14±7)days. (2) Postoperative situations. Fifteen of 49 patients underwent postoperative complications, including 8 cases with grade Ⅱ Clevien-Dindo complications and 7 cases with ≥grade Ⅲ Clevien-Dindo complications. None of 49 patient underwent postoperative transferring to intensive care unit and no patient died during hospitalization. Results of postoperative histopathological examination in 23 patients with tumor local recurrence showed negative incision margin of the surgical specimen. (3) Follow-up. All 49 patients underwent post-operative follow-up of 90 days. There were 42 cases undergoing redo rectal resection and coloanal anastomosis successfully and 7 cases failed. Of the 37 patients with enterostomy, 20 cases failed in closing fistula, and 17 cases succeed. There were 46 patients receiving follow-up with the median time as 16.1(7.5,34.6)months. The questionnaire response rate for low anterior resection syndrome (LARS) score was 48.3%(14/29). Of the patients who underwent redo coloanal anastomosis and closure of stoma successfully, there were 9 cases with mild-to-moderate LARS.Conclusion:Redo rectal resection and coloanal anastomosis is safe and feasible for patients undergoing local recurr-ence of tumors and failure of colorectal or coloanal anastomosis after rectal resection, which can successfully restore intestinal continuity in patients and avoid permanent enterostomy.

Objective:To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury.Methods:This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded.Results:The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100–6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions:TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.

Objective:To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury.Methods:This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded.Results:The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100–6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions:TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.

Objective:To establish a correlation model between MRI and CT images to generate synthetic-CT (sCT) of head and neck cancer during MRI-guided radiotherapy by using generative adversarial networks (GAN).Methods:Images and IMRT plans of 45 patients with nasopharyngeal carcinoma were collected before treatment. Firstly, the MRI (T1) and CT images were preprocessed, including rigid registration, clipping, background removal and data enhancement, etc. Secondly, the cases were trained by GAN, of which 30 cases were randomly selected and put into the network as training set images for modeling and learning, and the other 15 cases were used for testing. The image quality of predicted sCT and real CT were statistically compared, and the dose distribution recalculated upon predicted sCT was statistically compared with that of real planned dose distribution.Results:The mean absolute error of the predicted sCT of the testing set was (79.15±11.37) HU, and the SSIM value was 0.83±0.03. The MAE values of dose distribution difference at different regional levels were less than 1% compared to the prescription dose. The gamma passing rate of the sCT dose distribution was higher than 92% and 98% under the 2mm/2% and 3mm/3% criteria.Conclusions:We have successfully proposed and realized the generation of sCT for head and neck cancer using GAN, which lays a foundation for the implementation of MRI-guided radiotherapy. The comparison of image quality and dosimetry shows the feasibility and accuracy of this method.

Objective:To compare the accuracy and generalized robustness of three predictive models of knowledge-based treatment strategies for radiotherapy for optimized model selection.Methods:The clinical radiotherapy plans of 45 prostate cancer (PC) cases and 25 nasopharyngeal cancer (NPC) cases were collected, and analyzed using three models (Z, L and S model), proposed by Zhu et al, Appenzoller et al and Shiraishi et al, respectively, to predict the dose-volume histogram (DVH) of bladder and rectum on PC cases and that of left and right parotid on NPC cases. The prediction error was measured by the difference of area under the predicted DVH and the clinical DVH curves (|V (pre_DVH)-V (clin_DVH)|), where a smaller prediction error implies a greater prediction accuracy. The accuracies of these three models were compared on the single organ at risk (OAR), and the generalized robustness of models was evaluated and compared by calculating the standard deviation of the prediction accuracy on different OAR. Results:For bladder and rectum, the prediction error of L model (0.114 and 0.163, respectively) was significantly higher than those values of Z and S models (≤0.071, P<0.05); for left parotid gland, the predicted error of S model (0.033) did not present significant difference from those values of Z and L models (≤0.025, P>0.05); for right parotid gland, S model (0.033) demonstrated significantly higher prediction error than those of Z and L models (≤0.028, P<0.05). Regarding different OAR, S model showed a lower standard deviation of prediction accuracy when comparing to Z and L models (0.016, 0.018 and 0.060, respectively). Conclusions:In the prediction of DVH in bladder and rectum of PC, Z and S models were more accurate than L model. In contrast, Z and L models demonstrated higher accuracy than S model in the prediction of left and right parotid glands of NPC. In respect to different OAR, the generalized robustness of S model was superior than the other two models.