Objective To evaluate the efficacy of staged carotid artery stenting and coronary artery bypass grafting in the treatment of coronary heart disease complicated with carotid stenosis. Methods The clinical data of patients with coronary heart disease and carotid stenosis treated in Fuwai Hospital from November 2019 to September 2021 were retrospectively analyzed. All patients underwent staged carotid artery stenting and coronary artery bypass grafting. The incidence and risk factors of severe complications such as myocardial infarction, cerebral infarction and death during the perioperative period and follow-up were analyzed. Results A total of 58 patients were enrolled, including 47 males and 11 females with an average age of 52-77 (64.2±5.6) years. No complications occurred before coronary artery bypass grafting. There was 1 myocardial infarction, 1 cerebral infarction and 1 death after the coronary artery bypass grafting. The early complication rate was 5.2%. During the follow-up of 18.3 months, 1 cerebral infarction and 2 deaths occurred, and the overall complication rate was 10.3%. According to Kaplan-Meier survival curve analysis, patients with symptomatic carotid stenosis (log-rank, P=0.037) and placement of close-cell (log-rank, P=0.030) had a higher risk of postoperative ischemic cerebrovascular event, and patients with previous cerebral infarction had a higher risk of postoperative severe complications (log-rank, P=0.044). Conclusion Staged carotid artery stenting and coronary artery bypass grafting is safe and feasible for the treatment of coronary heart disease complicated with carotid stenosis.

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 investigate the role of three-dimensional dose distribution-based deep learning model in predicting distant metastasis of head and neck cancer.Methods:Radiotherapy and clinical follow-up data of 237 patients with head and neck cancer undergoing intensity-modulated radiotherapy (IMRT) from 4 different institutions were collected. Among them, 131 patients from HGJ and CHUS institutions were used as the training set, 65 patients from CHUM institution as the validation set, and 41 patients from HMR institution as the test set. Three-dimensional dose distribution and GTV contours of 131 patients in the training set were input into the DM-DOSE model for training and then validated with validation set data. Finally, the independent test set data were used for evaluation. The evaluation content included the area under receiver operating characteristic curve (AUC), balanced accuracy, sensitivity, specificity, concordance index and Kaplan-Meier survival curve analysis.Results:In terms of prognostic prediction of distant metastasis of head and neck cancer, the DM-DOSE model based on three-dimensional dose distribution and GTV contours achieved the optimal prognostic prediction performance, with an AUC of 0.924, and could significantly distinguish patients with high and low risk of distant metastasis (log-rank test, P<0.001). Conclusion:Three-dimensional dose distribution has good predictive value for distant metastasis in head and neck cancer patients treated with IMRT, and the constructed prediction model can effectively predict distant metastasis.

Objective:To investigate the predictive value of serum vascular endothelial growth factor (VEGF), squamous cell carcinoma-associated antigen (SCCAg) and miRNA let-7a in lymph node metastasis and postoperative recurrence in patients with laryngeal cancer.Methods:A total of 82 patients with laryngeal cancer in the Second Central Hospital of Baoding from November 2017 to October 2019 were selected as the research subjects, including 18 cases of lymph node metastasis (metastasis group) and 64 cases of non metastasis (non metastasis group). The blood routine was tested before operation, and the baseline data, serum VEGF, SCCAg and miRNA let-7a levels were compared between the two groups. Logistic regression was used to analyze the related influencing factors of lymph node metastasis in patients with laryngeal cancer. The correlation between serum VEGF, SCCAg, miRNA let-7a levels and clinicopathological characteristics was analyzed. The receiver operating characteristic (ROC)curve was used to analyze the value of each index and the combined diagnosis of lymph node metastasis in patients with laryngeal cancer. After 1 year of follow-up, the serum VEGF, SCCAg and miRNA let-7a levels of patients with or without recurrent laryngeal cancer were compared. ROC curve was used to evaluate the value of VEGF, SCCAg, and miRNA let-7a in predicting the recurrence of laryngeal cancer.Results:There were statistically significant differences in tumor node metastasis (TNM) stage, degree of infiltration, degree of differentiation, serum VEGF, SCCAg, and miRNA let-7a levels between the metastasis group and non metastasis group (all P<0.05). Serum VEGF, SCCAg, miRNA let-7a levels in patients with laryngeal cancer were related to TNM stage, degree of infiltration and degree of differentiation (all P<0.05). The combined diagnosis of serum VEGF, SCCAg and miRNA let-7a levels in the diagnosis of lymph node metastasis in patients with laryngeal cancer showed that the diagnostic sensitivity and specificity were 88.89% and 70.31%, respectively. The serum VEGF and SCCAg levels of patients with recurrence after operation were higher than those without recurrence, and the level of miRNA let-7a was lower than those without recurrence (all P<0.05). The sensitivity and specificity of combined serum VEGF, SCCAg and miRNA LET-7a levels in predicting postoperative recurrence of laryngeal cancer were 72.97% and 91.11%, respectively. Conclusions:VEGF, SCCAg, miRNA let-7a in patients with laryngeal cancer have a certain correlation with clinicopathological characteristics, which can assist in the diagnosis of lymph node metastasis and help clinical prediction of postoperative recurrence in patients with laryngeal cancer, and provide a reference for the formulation of clinical treatment plans.

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 clinical feasibility of the Unity radiotherapy system guided by magnetic resonance imaging.Methods:Twenty-four patients were enrolled and received a total of 384 fractions of treatment at Unity system. According to the treatment site, all patients were divided into head-neck, abdomen-thorax, pelvic, spine and limb groups. The patients were set-up without external laser. And then, the time required at different stages in online treatment process and the registration error of each fraction were separately calculated. The geometric deformations of MR images were weekly measured by using MR geometric deformation phantom. At last, the Arccheck was used to perform the dose verification of reference plan, online plan and offline plan.Results:The mean duration of radiotherapy in the five groups were 29.1, 27.6, 26.6, 25.6 and 32.0 min, respectively. The set-up errors in the left-right, superior-inferior and anterior-posterior direction in the five groups were: head-neck group (0.08±0.06 cm, 0.16±0.13 cm, 0.08±0.05 cm), abdomen-thorax group (0.23±0.18 cm, 0.50±0.47 cm, 0.12±0.1 cm), pelvic group (0.25±0.19 cm, 0.32±0.25 cm, 0.11±0.09 cm), spine group (0.46±0.38 cm, 0.26±0.26 cm, 0.13±0.07 cm) and limb group (0.33±0.30 cm, 0.34±0.23 cm, 0.08±0.06 cm), respectively. In the central region, the geometric deformation of MR was less than 0.3 mm, and that of the sphere with a diameter of 500 mm was less than 2.1 mm. The meanγ pass rate of the reference plan, online plan and offline plan were 97.92%, 97.84% and 94.58%, respectively.Conclusions:MR-guided radiotherapy has great potential for clinical application, whereas the process of Unity system is relatively complex. The synergy of different departments has a great impact on the treatment, which needs further optimization.

Objective:To characterize the imaging distortion of the 1.5T magnetic resonance imaging-guided linear accelerator (MR-Linac) and to analyze the influence of MR-Linac and peripheral devices on the geometric distortion.Methods:Specialized MRI imaging distortion phantom and analysis software were applied. The baseline of imaging distortion within diameter spherical volume (DSV) around the center of the magnet was established. The influence of the beam generation system, mechanical system and peripheral devices on the imaging distortion was analyzed. The long-term stability of imaging distortion was tested on the MR-Linac.Results:Imaging distortion of the MR-Linac was increased with the increasing distance to the center of the magnet. Within DSV 400 mm, few test points surpassed 1 mm imaging distortion in 3D directions. However, imaging distortion surpassed 2 mm in part of region within DSV 400-500 mm, with the largest distortion over 7 mm. Imaging distortion of the MR-Linac remained unchanged within 7 months after installation. And the influence of the MR-Linac and peripheral devices on the imaging distortion was only observed in the overall largest distortion within DSV 400-500 mm.Conclusions:Cautions should be taken during the application of high-field MR-Linac in patients whose tumor location is over 20 cm from the ISO center. Imaging distortion of the MR-Linac remains stable within 7 months after installation. The influence of the MR-Linac and peripheral devices on the imaging distortion is trivial, which can be neglected in clinical practice.

Objective:To establish an automatic segmentation network based on different receptive fields for gross target volume (GTV) and organs at risk in patients with nasopharyngeal carcinoma.Methods:Radiotherapy data of 100 cases of nasopharyngeal carcinoma including CT images and GTV and organs at risk delineated by the physicians were collected. Ninety plans were randomly selected as the training dataset, and the other 10 plans as the validation dataset. Firstly, the images were subject to three data augmentation methods including center cropping, vertical flipping and rotation (-30°to 30°), and then input into MA_net networks proposed in this study for training. The model performance of networks was assessed by the number of network parameters (NP), floating-point number (FPN), the running memory (RM) and Dice index (DI), and eventually compared with DeeplabV3+ , PSP_net, UNet+ + and U_Net networks.Results:When the input image was in the size of 240×240, MA_net had a NP of 23.20%, 20.10%, 25.55% and 27.11% of these 4 networks, 50.02%, 19.86%, 6.37% and 13.44% for the FPN, 40.63%, 23.60%, 11.58% and 14.99% for the RM, respectively. For the DI of GTV, MA_net was 1.16%, 2.28%, 1.27% and 3.59% higher than these 4 networks. For the average DI of GTV and OAR, MA_net was 0.16%, 1.37%, 0.30% and 0.97% higher than these 4 networks.Conclusion:Compared with those four networks, the proposed MA_net network has slightly higher Dice index with fewer parameters, lower FPN and smaller RM.

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.