OBJECTIVE To develop a magnetic resonance(MRI) imaging radiomics and clinical factor model to predict recurrence and metastasis in patients with primary stage Ⅱ-Ⅳa nasopharyngeal carcinoma(NPC) and to validate its predictive effect on adjuvant chemotherapy(AC) outcomes. METHODS A retrospective analysis was performed on 135 patients with stage Ⅱ to Ⅳa NPC diagnosed in Longgang Otolaryngology Hospital of Shenzhen City from February 2018 to October 2021. After receiving standard synchronous radiotherapy and chemotherapy at our hospital,some patients received induction chemotherapy and/or AC based on cisplatin/nedaplatin. The imaging features of enhanced MRI sequences were extracted using PyRadiomics platform. Using the least absolute shrinkage and selection operator(LASSO) algorithm to filter features associated with recurrence or metastasis,a clinical radiomics model(CRM) was constructed by Cox multivariate analysis in a training cohort and validated in a validation cohort. All patients were divided into high-risk and low-risk groups based on the model's median Rad score. Kaplan-Meier survival curves were used to compare 3-year recurrence or metastasis free survival(RMFS) in patients with AC in high-risk group and low risk-group. RESULTS A total of 960 imaging features were extracted. The CRM consists of 9 features(6 imaging features and 3 clinical factors). In the training cohort,the area under the CRM curve(AUC) of 3-year RMFS was 0.867(P<0.001),and the sensitivity and specificity were 90.32％ and 79.66％,respectively. In the validation cohort,the AUC was 0.836(P<0.001) and the sensitivity and specificity were 100.0％ and 71.43％,respectively. The 3-year RMFS in high-risk and low-risk groups was 42.86％(27/63) and 94.44％(68/72)(log rank=50.818,P<0.001),respectively. Among CRM high-risk patients,3-year RMFS was significantly better in patients who received AC than those who did not(log rank=6.204,P=0.013). CONCLUSION CRM based on 3 clinical factors and 6 MRI features provides a non-invasive method for predicting the prognosis of NPC,which may help guide treatment decisions for clinical adjuvant chemotherapy,but further external verification is needed.

Objective:To evaluate the feasibility of predicting lung cancer target position by online optical surface motion monitoring.Methods:CT images obtained in different ways of stereotactic body radiotherapy (SBRT) plans from 16 lung cancer cases were selected for experimental simulation. The planned CT and the original target position were taken as the reference, and the 10 phases of CT in four dimension CT and each cone beam (CBCT) were taken as the floating objects, on which the floating target location was delineated. The binocular visual surface imaging method was used to obtain point cloud data of reference and floating image body surface, while the point cloud feature information was extracted for comparison. Based on the random forest algorithm, the feature information difference and the corresponding target area position difference were fitted, and an online prediction model of the target area position was constructed.Results:The model had a high prediction success rate for the target position. The variance explainded and root mean squared error ( RMSE) of left-right, superior-inferior, anterior-posterior directions were 99.76%, 99.25%, 99.58%, and 0.0447 mm, 0.0837 mm, 0.0616 mm, respectively. Conclusion:The online monitoring of lung SBRT target position proposed in this study is feasible, which can provide reference for online monitoring and verification of target position and dose evaluation in clinical radiotherapy.

Objective:To propose a markerless beam's eye view (BEV) tumor tracking algorithm, which can be applied to megavolt (MV) images with poor image quality, multi-leaf collimator (MLC) occlusion and non-rigid deformation.Methods:Window template matching, image structure transformation and demons non-rigid registration method were used to solve the registration problem in MV images. The quality assurance (QA) plan was generated in the phantom and executed after manually setting the treatment offset on the accelerator, and 682 electronic portal imaging device (EPID) images in the treatment process were collected as fixed images. Meanwhile, the digitally reconstructured radiograph (DRR) images corresponding to the field angle in the planning system were collected as floating images to verify the accuracy of the algorithm. In addition, a total of 533 images were collected from 21 cases of lung tumor treatment data for tumor tracking study, providing quantitative results of tumor location changes during treatment. Image similarity was used for third-party verification of tracking results.Results:The algorithm could cope with different degrees (10%-80%) of image missing. In the phantom verification, 86.8% of the tracking errors were less than 3 mm, and 80% were less than 2 mm. Normalized mutual information (NMI) varied from 1.182±0.026 to 1.202±0.027 ( P<0.005) before and after registration and the change of Hausdorff distance (HD) was from 57.767±6.474 to 56.664±6.733 ( P<0.005). The case results were predominantly translational (-6.0 mm to 6.2 mm), but non-rigid deformation still existed. NMI varied from 1.216±0.031 to 1.225±0.031 ( P<0.005) before and after registration and the change of HD was from 46.384±7.698 to 45.691±8.089 ( P<0.005). Conclusions:The proposed algorithm can cope with different degrees of image missing and performs well in non-rigid registration with data missing images which can be applied in different radiotherapy technologies. It provides a reference idea for processing MV images with multi-modality, partial data and poor image quality.

Abstract: Objective To investigate the clinical features and risk factors for severe tsutsugamushi disease, so as to provide reference for diagnosis and differentiation of severe tsutsugamushi disease as soon as possible. Methods The clinical data of 178 cases of inpatients with tsutsugamushi disease admitted to the Guangzhou Eighth People's Hospital, Guangzhou Medical University from January 2016 to September 2021 were collected and analyzed according to their gender, age, underlying diseases, clinical characteristics at admission, laboratory examination results within 24 hours of admission and epidemiological history. The patients were divided into the severe group and the non-severe group according to the diagnostic criteria. The data of clinical characteristics, laboratory examination and prognosis of the two groups were compared. Multivariate logistic regression analysis was performed on the variables with statistical significance and the receiver operating characteristic curve (ROC) was drawn. Results A total of 178 patients were included in this study, with 37 in the severe group and 141 in the non-severe group. Compared with the non-severe group, the age of the severe group was older, the underlying diseases were more, the incidence of dyspnea and the levels of white blood cell, total bilirubin, aspartate aminotransferase, lactate dehydrogenase, cystatin C, uric acid and serum creatinine were significantly increased, the levels of platelet and albumin were significantly decreased (all P<0.05). The dyspnea [odds ratio (OR value)=8.93, 95% confidence interval (CI): 1.200-66.424; P=0.032], total bilirubin (OR=1.091, 95%CI: 1.028-1.159; P=0.004) and serum creatinine (OR=1.052, 95%CI: 1.004-1.102; P=0.033) were independent risk factors for severe tsutsugamushi disease. The area under ROC curve of total bilirubin and serum creatinine were 0.777 and 0.764, respectively (both P<0.01), indicating high predictive value for severe tsutsugamushi disease. The optimal cut-off value for total bilirubin was 23.01 µmol/L, with a sensitivity of 54.10% and a specificity of 90.60%; the optimal cut-off value for creatinine was 126.45 µmol/L, with a sensitivity of 43.20% and a specificity of 100.00%. The case fatality rate of severe tsutsugamushi disease was 2.70%. Conclusions The patients with severe tsutsugamushi disease are older, and have more underlying diseases. Dyspnea, increased total bilirubin and elevated serum creatinine are independent risk factors for severe tsutsugamushi disease, which can help in the early identification of severe tsutsugamushi disease early.

Objective:To analyze the epidemiological and clinical characteristics of patients with tsutsugamushi disease in Guangdong Province from 2016 to 2021, and to provide a reference for clinical diagnosis, treatment, scientific prevention and control of tsutsugamushi disease.Methods:A retrospective analysis was conducted to collect the information of patients with tsutsugamushi disease admitted to Guangzhou Eighth Hospital Affiliated to Guangzhou Medical University from 2016 to 2021, including the basic information, epidemiological characteristics, clinical manifestations, auxiliary examinations, complications, misdiagnosis at first diagnosis and treatment outcomes.Results:Among 155 patients with tsutsugamushi disease, there were 75 males (48.39%) and 80 females (51.61%), with an e age of (54.41 ± 13.78) years old, and 30 cases (19.35%) had other underlying diseases. The peak time of onset was from June to September. There were 97 local patients (62.58%) in Guangzhou, and 58 cases (37.42%) in other prefecture-level cities; 76.77% (119/155) had a history of field activities before the onset of the disease. 36.13% (56/155) were farmers. The most common clinical manifestations were fever (100.00%, 155/155), chills and/or shivering (77.42%, 120/155), headache and/or dizziness (74.19%, 115/155), fatigue (65.81%, 102/155), eschar or ulcer (92.90%, 144/155), and lymphadenopathy (49.68%, 77/155). The laboratory test results mainly showed a decrease in eosinophils (81.94%, 127/155), a decrease in hematocrit (78.71%, 122/155), a decrease in hemoglobin (52.26%, 81/155), a decrease in platelet count (50.97%, 79/155), a decrease in albumin (92.26%, 143/155), an increase in lactate dehydrogenase (90.32%, 140/155), an increase in adenosine deaminase (88.39%, 137/155), and an increase in alanine aminotransferase (85.16%, 132/155), elevated aspartate aminotransferase (85.16%, 132/155), and elevated procalcitonin (52.90%, 82/155); 30 cases (19.35%) were positive for the Weil-Felix Test. There were 95 cases (61.29%) with abnormal chest imaging results, and 34 cases (21.94%) with abnormal abdominal ultrasound or CT results. Common complications were toxic hepatitis, pulmonary infection, organ failure, and acute kidney injury, etc. The misdiagnosis rate of the initial diagnosis of this disease was 75.48% (117/155). Doxycycline and symptomatic and supportive therapy were given, 154 patients (99.35%) were cured or improved and discharged from hospital.Conclusions:Tsutsugamushi disease is prevalent in summer and autumn in Guangdong Province. Before the onset, most of the patients have a history of field activities. Farmers are susceptible people. Its clinical manifestations are diverse, and can affect multiple systems and organs. There are many complications, and doxycycline can be used for anti-infection treatment, with a high cure rate.

Objective:To evaluate the changes in the systemic circulation and microcirculation in the patients undergoing gastrointestinal surgery under general anesthesia in Xining area.Methods:A total of 27 patients, aged 18-60 yr, underwent gastrointestinal surgery under general anesthesia in Xining area (2 260 m), of long lived (more than two generations) Han nationality, with no alternating life between plateau and plain, with no cardiopulmonary abnormalities, were enrolled.Anesthesia was induced with midazolam, sufentanil, etomidate, and cisatracurium and maintained with propofol, remifentanil and cisatracurium.At 5 min before induction of anesthesia (T 1), 10 min after induction of anesthesia (T 2), 1 h after start of operation (T 3), immediately after the end of operation (T 4), and 30 min after recovery from anesthesia (T 5), systemic circulation indexes including cardiac output (CO), stroke volume (SV), stroke volume variability (SVV), systemic vascular resistance index (SVRI), and mean arterial pressure (MAP) and heart rate (HR) were recorded, and sublingual microcirculation indexes including total vascular density (TVD), perfused vessel density (PVD), portion of perfused vessels (PPV), and microvascular flow index (MFI) were determined by sidestream dark field imaging. Results:Systemic circulation Compared with the baseline at T 1, CO and HR were significantly decreased at T 2-4, SVV was decreased at T 5, SVRI was increased at T 3 and T 4, and MAP was decreased at T 2 ( P<0.05). Compared with those at T 2, CO and SV were significantly increased at T 5, SVV was decreased at T 5, SVRI was increased at T 3 and T 4, and MAP was increased at T 4 and T 5 ( P<0.05). Compared with those at T 3, SV was significantly decreased at T 4, CO was increased at T 5, and SVV and SVRI were decreased at T 5 ( P<0.05); Compared with those at T 4, CO, SV and HR were significantly increased at T 5, and SVV and SVRI were decreased at T 5 ( P<0.05). Microcirculation Compared with those at T 1, TVD, PVD, PPV and MFI were significantly decreased at T 2-4, and PPV and MFI were decreased at T 5 ( P<0.05). Compared with those at T 2, TVD was significantly increased at T 5, PVD was increased at T 4 and T 5, and PPV was increased at T 3 and T 4 ( P<0.05). TVD was significantly higher at T 5 than at T 3( P<0.05). TVD was significantly higher at T 5 than at T 4 ( P<0.05). Conclusions:The density of microcirculation and blood flow rate are decreased after induction of general anesthesia and during anesthesia operation, which are most significant at the initial stage after induction, and decoupling between systemic circulation and microcirculation occurs during operation and anesthesia resuscitation in the patients at high altitude.

Objective:To propose a machine learning-based markerless beam′s eye view (BEV) tumor tracking algorithm that can be applied to low-quality megavolt (MV) images with multileaf collimator (MLC)-induced occlusion and non-rigid deformation.Methods:This study processed the registration of MV images using the window template matching method and end-to-end unsupervised network Voxelmorph and verified the accuracy of the tumor tracking algorithm using dynamic chest models. Phantom QA plans were executed after the treatment offset was manually set on the accelerator, and 682 electronic portal imaging device (EPID) images obtained during the treatment were collected as fixed images. Moreover, the digitally reconstructed radiography (DRR) images corresponding to the portal angles in the planning system were collected as floating images for the study of target volume tracking. In addition, 533 pairs of EPID and DRR images of 21 lung tumor patients treated with radiotherapy were collected to conduct the study of tumor tracking and provide quantitative result of changes in tumor locations during the treatment. Image similarity was used for third-party validation of the algorithm.Results:The algorithm could process images with different degrees (10%-80%) of data missing and performed well in non-rigid registration of images with data missing. As shown by the phantom verification, 86.8% and 80% of the tracking errors were less than 3 mm and less than 2 mm, respectively, and the normalized mutual information (NMI) varied from 1.18 ± 0.02 to 1.20 ± 0.02 after registration ( t = -6.78, P = 0.001). The tumor motion of the clinical cases was dominated by translation, with an average displacement of 3.78 mm and a maximum displacement of 7.46 mm. The registration result of the cases showed the presence of non-rigid deformations, and the corresponding NMI varied from 1.21 ± 0.03 before registration to 1.22 ± 0.03 after registration ( t = -2.91, P = 0.001). Conclusions:The tumor tracking algorithm proposed in this study has reliable tracking accuracy and high robustness and can be used for non-invasive and real-time tumor tracking requiring no additional equipment and radiation dose.

Objective:To propose a method of image similarity measurement based on structure information and intuitionistic fuzzy set and measure the similarity between CT image and CBCT image of radiotherapy plan positioning, aiming to objectively measure the setup errors.Methods:A total of four pre-registration images of a nasopharyngeal carcinoma patient on the cross-sectional and sagittal planes and a pelvic tumor patient on the cross-sectional and coronal planes were randomly selected. Five methods were used to quantify the setup errors, including correlation coefficient, mean square error, image joint entropy, mutual information and similarity measure method.Results:All five methods could describe the deviation to a certain extent. Compared with other methods, the similarity measure method showed a stronger upward trend with the increase of errors. After normalization, the results of five types of error increase on the cross-sectional plane of the nasopharyngeal carcinoma patient were 0.553, 0.683, 1.055, 1.995, 5.151, and 1.171, 1.618, 1.962, 1.790, 3.572 on the sagittal plane, respectively. The results of other methods were between 0 and 2 after normalization, and the results of different errors of the same method slightly changed. In addition, the method was more sensitive to the soft tissue errors.Conclusions:The image similarity measurement method based on structure information and intuitionistic fuzzy set is more consistent with human eye perception than the existing evaluation methods. The errors between bone markers and soft tissues can be objectively quantified to certain extent. The soft tissue deviation reflected by the setup errors is of significance for individualized precision radiotherapy.

Objective:To explore the clinical characteristics of imported malaria from Africa, and the correlation between blood lipids and disease severity.Methods:The clinical data of 172 imported malaria patients from Africa were collected from January 1, 2018 to January 31, 2021 in Guangzhou Eighth People′s Hospital, Guangzhou Medical University. The general conditions, clinical symptoms, laboratory tests, treatment and prognosis of the patients were analyzed retrospectively. The independent samples t-test, Mann-Whitney U test and binary multivariate logistic regression analysis were used for statistical analysis when appropriate. Results:A total of 172 patients were divided into 39 severe cases and 133 non-severe cases in this study. The main infection species was Plasmodium falciparum, with a total of 153 cases (89.0%), and the severe cases were all falciparum malarias. Compared with the non-severe group, the white blood cell count and triacylglycerol level were increased in the severe group.The differences were both statistically significant ( Z=2.397 and 4.368, respectively; both P<0.05). The hemoglobin, hematocrit, platelet count, high-density lipoprotein cholesterol, apolipoprotein A (ApoA)Ⅰ and ApoAⅠ/apolipoprotein B (ApoB) were significantly decreased in the severe group. The differences were all statistically significant ( Z=-4.473, -4.464, -4.750, -4.826, -5.488 and -4.419, respectively; all P<0.01). The total cholesterol and low-density lipoprotein cholesterol were also reduced in the severe group. The differences were both statistically significant ( t=3.817 and 5.285, respectively; both P<0.01). The area under receiver operator characteristic curve of high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, ApoAⅠ, and ApoAⅠ/ApoB were 0.754, 0.727, 0.730, 0.789 and 0.733, respectively (all P<0.01). When the Youden index was at its maximum, the best cut-off value of ApoAⅠ was 0.535 g/L with sensitivity of the prediction for severe malaria of 79.5% and the specificity of 68.4%. ApoAⅠ had independent predictive value for severe malaria (odds ratio ( OR)=0.013, 95% confidence interval ( CI) 0.002 to 0.086, P<0.01), and stratified according to the best cut-off value, the risk of severe malaria when ApoA Ⅰ<0.535 g/L was 8.396 times of ApoA Ⅰ≥0.535 g/L ( OR=8.396, 95% CI 3.557 to 19.820, P<0.01). The case fatality rate of severe malaria was 2.6%(1/39). Conclusions:The imported malaria patients from Africa are mainly infected with Plasmodium falciparum and the case fatality rate of severe malaria is high. The high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triacylglycerol, ApoAⅠ, ApoAⅠ/ApoB of blood lipids show higher predictive value for severe malaria, among which, ApoAⅠ has independent predictive value for severe malaria. Changes in blood lipids will help to identify severe malaria as early as possible, improve the cure rate, and reduce the risk of death.

Objective: To quantitatively evaluate dose accuracy of radiotherapy for cervical cancer. Methods: A CT image correction algorithm based on image transformation was proposed. Referring to CBCT images, CT images of radiotherapy plan for cervical cancer were corrected to obtain the corrected images which could reflect the actual body position of treatment. The clinical plan was transplanted to the corrected images for dose recalculation as a test plan, and the dosimetry parameters were statistically compared to evaluate the dose accuracy. Results: Both of the target coverage of contrast plans could meet the clinical requirements (>98%), and there was no significant difference in the homogeneity index (P=0.150). The conformability of the test plan was significantly worse than that of the clinical plan (P<0.05). The maximum dose of each organ at risk in the test plan was approximately 30 cGy higher than that of the clinical plan (P<0.05), V₅₀ was slightly higher than that of the clinical plan, whereas the average dose (D_mean) did not significantly differ. Conclusion The CT image correction algorithm based on image transformation can quantitatively evaluate the dose accuracy of radiotherapy for cervical cancer, which provides reference for resolving similar problems in clinical practice.