OBJECTIVE: To study effective methods for reducing lung V₅, V₁₀, and mean lung dose (MLD) in the design of volumetric modulated arc therapy for central lung cancer by using different arc configurations and dose-limiting blocks designs. METHODS: Five groups of plans were designed for the enrolled patients. Group A used a full-arc field. Group B used a partial-arc field. Groups C, D, and E used full-arc fields with vertical-length, semi-ring, and triangular dose-limiting blocks added respectively. The dosimetric similarities of target areas and the dosimetric differences in lung V₅, V₁₀, V₂₀, and MLD among the groups were compared. RESULTS: Compared with group A, groups B, C, D, and E had decreased homogeneity and conformity of the target area, but significantly lower V₅ and V₁₀ of the whole lung. The MLD of groups C, D, and E was lower than that of group A. CONCLUSION Using a full-arc field combined with dose-limiting blocks can effectively reduce lung V₅, V₁₀, MLD, and monitor units (MU).
Lung Neoplasms/radiotherapy* ; Humans ; Radiotherapy, Intensity-Modulated/methods* ; Radiotherapy Planning, Computer-Assisted/methods* ; Radiotherapy Dosage ; Lung/radiation effects*

Objective:To explore the radiological damage to cells induced by the delayed particles of 9C-ions for heavy ion therapy, as well as the microdosimetric distribution and biological effects of these particles on a single model of V79 Chinese hamster lung cells. Methods:The Monte Carlo program was employed to simulate the endonuclear absorbed doses of α particles with various energies (3-10 MeV) transported in cells (cell radius RC = 10 μm, nucleus radius RN = 5 μm). Then, the result were compared with the S values ( SN←N, SN←Cy, and SN←CS) derived using the medical internal radiation dose (MIRD) method to demonstrate the feasibility of Monte Carlo simulations. Finally, the energy deposition of the delayed particles of 9C-ions generated at three sites (i.e., on the surface and in the cytoplasm and nucleus of the V79 cell model) during their transport in targets was simulated, and the result ing cell surviving fraction was analyzed. Results:Monte Carlo and MIRD method yielded differences in S values of 1.91%-4.95% for SN←N (nucleus to nucleus), 1.48%-5.11% for SN←Cy (cytoplasm to nucleus), and -1.99% to 0.80% for SN←CS(surface to nucleus), indicating highly consistent S values derived using both method(differences < 6%). When a 9C-ion decayed on the surface of the V79 cell model and the produced secondary particles entered the cell, the average endonuclear absorbed dose was 10 -2 Gy orders of magnitude, with a cell surviving fraction of about 88%. In the case where decay occurred in the cytoplasm, the cell surviving fraction was about 80%. However, when the 9C ion decayed in the nucleus, α particles had short ranges and deposited most of their energy in the cell (mean endonuclear absorbed dose: 0.1 Gy). In this case, severe cell damage was induced, with the cell surviving fraction reducing to about 53%. Conclusions:9C-ions emit secondary charged particles due to decay, among which α particles cause great damage to cells when entering the nucleus and trigger evident biological effects.

Objective:To understand the epidemiological characteristics and spatiotemporal distribution of viral encephalitis in children and adolescents in Henan Province from 2012 to 2023.Methods:The information about viral encephalitis cases from October 1, 2012 to July 26, 2023 were collected from Zhengzhou Children's Hospital (National Children's Regional Medical Center),Henan Provincial Children's Hospital for the analyses on temporal distribution the cases, the severe illness rate, age distribution, pathogen type and imaging findings of the cases.Results:A total of 6 276 cases of viral encephalitis were included in this study after excluding cases with incomplete information. The cases mainly originated from Zhengzhou (38.96%), followed by Zhoukou (9.93%), Xuchang (8.68%), Zhumadian (7.90%) and Pingdingshan (7.39%). The cases in boys accounted for 62.13% and the cases in girls accounted for 37.87%. Most cases (72.45%) occurred in age group 7-13 years. The overall rate of severe illness cases was 4.51% from 2012 to 2023. There were significant differences in severe illness cases among different areas and years ( χ2=5.33, P=0.021; χ2=48.14, P<0.001). Enteroviruses were mainly detected (31.57%), in which Coxsackie virus was predominant (58.37%). Imaging findings showed that cerebral hemisphere damage was most common in children and adolescents with viral encephalitis (54.93%). Conclusions:From 2012 to 2023, more cases of viral encephalitis occurred in boys in Henan. Children and adolescents aged 7-13 years were the main affected group. The prevention of enteroviruses infection, especially Coxsackie virus, needs to be strengthened. Special attention should be paid to the prevention of cerebral hemisphere damage after viral encephalitis diagnosis.

ObjectiveTo investigate the characteristics of gender difference and the trend of the mortality rate of senile dementia in registered population in Shanghai from year 2002 to 2018， and to provide the basis for formulating relative intervention measures before and after senile dementia from an public-health view. MethodsBased on the collected data of death registration， focused on the senile dementia disease codes F03，G30.0，G30.1，G30.8，G30.9 according to The International Classification of Diseases 10th revision （ICD-10）. We analyzed the characteristics of gender difference in the mortality rate of senile dementia in registered population in Shanghai from year 2002 to 2018. According to ASR， we calculated the standardized mortality rate of senile dementia， and used the chi-square test to compare the difference between the gender mortality rates. The trend and the turning point of the mortality rate of senile dementia were determined by linear regression analysis by Join-point. ResultsThe crude mortality rate of senile dementia in the registered population in Shanghai from year 2002 to 2018 was 5.46/10⁵， 3.50/10⁵ in males and 7.43/10⁵ in females. The standardized mortality rate of senile dementia was 2.61/10⁵， 1.67/10⁵ in males and 3.56/10⁵ in females. The trend of the standardized mortality rate of senile dementia in 17 years decreased ［APC=-5.5（-6.5，-4.5）%，P<0.01］. The trend of the standardized mortality rate of senile dementia decreased in both males ［APC=-4.9（-6.2，-3.6）%，P<0.01］ and females ［APC=-5.9（-6.9，-4.9）%，P<0.01］. The trend of the gender difference decreased ［APC=-6.8（-8.2，-5.3）%，P<0.01］. The mortality rate of senile dementia was higher in females than in males ［（χ²=33.63，P<0.01）］. ConclusionThe mortality rate of senile dementia in females is higher than in males in Shanghai， though the trend of the gender difference decreased. This gender difference is worth of attention.

ObjectiveTo analyze the dynamic response relationship between urban development and mortality rate in Shanghai， and to predict the trend of mortality rate changes. MethodsBy analyzing the total mortality rate （TMR）， gross domestic product （GDP） and socio-demographic index （SDI） in Shanghai from 1978 to 2017， a vector autoregressive （VAR） model was constructed to evaluate the impact of urban development on the mortality rate. ResultsThe fitted R2 of the VAR model was 0.92. The short-term effect of GDP on the improvement of death level was negative， while the long-term effect was positive， and the SDI was negative regardless of the short-term and long-term effects. By the tenth year， GDP and SDI contributed 10.61% and 27.25% to TMR changes， respectively. The model predicted that the mortality rate in Shanghai would be 9.17 per thousand by 2030. ConclusionLong-term economic growth can effectively promote a decline in population mortality. However， as the economy develops vigorously， the adverse effects of declining birth rates and population aging on population health during the era of high-level population development should not be ignored.

Due to the availability of 18F-FDG in PET centers, this article aims to advocate and promote the standardization of 18F-FDG PET brain imaging in dementia in order to improve the reliability, repeatability and comparison of the imaging process and results. It is also provided to guide the PET imaging operation standard and to give suggestions on image interpretation.

Objective To evaluate the application value of three-dimensional speckle tracking imaging (3D-STI) in quantitatively evaluating the left ventricular global strain in recipients within 3 months after renal transplantation. Methods Clinical data including blood pressure, serum creatinine and tacrolimus blood concentration of 34 renal transplant recipients were collected before operation, 7 d, 1 month and 3 months after operation, respectively. Meanwhile, conventional echocardiography and 3D-STI examination were performed. Echocardiographic parameters [left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF)] and 3D-STI parameters [left ventricular global peak longitudinal strain (GPLS), global peak circumferential strain (GPCS), global peak radial strain (GPRS) and global peak area strain (GPAS)] of recipients were collected. The changes of these parameters before operation, 7 d, 1 month and 3 months after operation were statistically compared. The changing characteristic and application value of 3D-STI in quantitatively evaluating the left ventricular global strain in recipients within 3 months after renal transplantation were evaluated. Results LVEF and GPCS did not significantly differ at different time points (all P > 0.05), whereas LVEDV, LVESV, GPLS, GPAS and GPRS significantly differed at different time points from preoperative to within postoperative 3 months (all P < 0.001). GPLS, GPAS and GPRS trended to decline within postoperative 1 month, and slightly increased at 3 months after operation, which was still lower than the preoperative levels. Conclusions Application of 3D-STI may sensitively detect the changes of left ventricular global strain in recipients after renal transplantation when no significant variations are observed in postoperative LVEF. Compared with conventional echocardiography, 3D-STI may more accurately evaluate the changes of left ventricular global strain in recipients after renal transplantation.

Objective:To construct a random forest classification model of DNA double strand breaks (DSB) induced by ionizing radiation and investigate the genome-wide distribution of DSB.Methods:The GRCh38 reference genome was divided into 50 kilobase fragments. Then these genomic fragments were separated into low-level or high-level regions of ionizing radiation-induced DSB according to the sequencing data of MCF-7 cells. The data of eight epigenetic features were used as input. Two thirds of the data were randomly assigned to the training set, and the rest of the data was assigned to the test set. A random forest classification model with 100 decision trees was constructed. The importance of epigenetic features in the classification model was analyzed and displayed.Results:The accuracy score of the random forest classification model on the test set was 99.4%, the precision score was 98.9% and the recall score was 99.9%. The area under the receiver operating characteristic curve was 0.994. Among the eight epigenetic features, H3K36me3 and DNase markers were the most important variables. The enrichments of the two markers in DSB high-level regions were much higher than those in DSB low-level regions.Conclusions:The random forest classification model could precisely predict the genome-wide levels of DSB induced by ionizing radiation in the 50 kilobase window based on epigenetic features. Analysis revealed that these DSB might primarily distribute in the actively transcribed sites in the genome.

Objective:To study the effects of gantry acceleration limitations of a linear accelerator (linac) on the dosimetry of volumetric modulated arc therapy (VMAT) plans, machine efficiency, and dose verification result of VMAT plans and to explore the optimal selection of gantry motion models in the Pinnacle treatment planning system.Methods:Ten cases of nasopharyngeal carcinoma, non-small cell lung cancer, sigmoid adenocarcinoma with retroperitoneal lymph node metastasis, and invasive ductal carcinoma of the breast were each selected for this study. Then two models were set up in the Pinnacle v9.10 treatment planning system, namely the one allowing gantry acceleration and the one limiting gantry acceleration. The same field arrangement, optimized target parameters, and optimized weights of VMAT plans were adopted in the two models, in order to analyze the dosimetric variations in targets and organs at risk (OARs) and compare the differences in treatment time and gamma passing rates.Results:The treatment time of the enrolled patients under the model allowing gantry acceleration was significantly lower than that of the patients under the model limiting gantry acceleration was adopted ( t=-6.751, -0.209, -19.523, -28.999; P< 0.05) and decreased by 15.27%, 18.07%, 19.71%, and 28.75%, respectively. Meanwhile, the conformity and uniformity of target areas were affected, while there was no statistical significance in the gamma passing rates in the validation of VMAT plans ( P>0.05). For the cases of nasopharyngeal carcinoma (NPC), the maximum dose to brainstem PRV increased by 1.25%. For the cases of lung cancer, the maximum dose to the spinal cord and lung V20 increased by 1.19% and 1.21%, respectively, while lung V5 decreased by 1.21%. For the cases of sigmoid adenocarcinoma with retroperitoneal lymph node metastasis, the mean doses to bilateral kidneys, livers, small intestine, and colon all increased. For the cases of breast cancer, lung V10 on the opposite side of cancer increased by 1.66% and the mean dose to the lungs on the same side of cancer decreased by 7.45%. Conclusions:The model allowing gantry acceleration allows the treatment time to be significantly shortened and the treatment efficiency improved. Although this model had the shortcomings such as affecting the conformity and uniformity of target areas to a certain extent and increasing the doses to some OARs, clinical requirements for dosimetry were still met. Therefore, it is recommended to use the model allowing gantry acceleration in the Pinnacle planning system.

Objective: To evaluate the long-term effect and safety of chrono-chemotherapy combined with intensity modulated radiotherapy (IMRT) in locally advanced nasopharyngeal carcinoma (NPC). Methods: 160 patients with locally advanced NPC were randomly divided into a chrono group and conventional group according to random number table. In the first stage, all patients underwent two cycles of induced chemotherapy, consisting of docetaxel, cisplatin and 5-Fu every 21 days. Notably, patients received chrono-moduated chemotherapy according to circadian rhythm in the chrono group, and conventional chemotherapy in the conventional group. Then, 21 days after the completion of first stage, three cycles of concurrent cisplatin chemotherapy every 21 days were given to all patients during IMRT. The median follow-up after the completion of radiotherapy was 31 months. Long-term side effects and the survival of patients were observed. Results: Patients in the chrono group had significantly lower rates of hearing loss (22.72%), dysphagia (0) and neck fibrosis (4.54%) compared with those in the conventional group (39.13%、8.69%, 15.94%, respectively, all P<0.05). Meanwhile, the 1- year overall survival rates (97.0% vs 92.8%), 3-year overall survival rates (80.3% vs 81.2%), 1-year progression free survival rates (95.5% vs 87.0%), 3-year progression free survival rates (71.2% vs 73.9%), 1-year locoregional relapse-free survival rates (97.0% vs 95.7%), 1-year locoregional relapse-free survival rates (92.4% vs 92.8%), 1-year distant metastasis-free survival rates (97.0% vs 98.6%) and 3-year distant metastasis-free survival rates (90.9% vs 91.3%) between the chrono group and the conventional group were not statistically significant (all P>0.05). Conclusions Compared with conventional chemotherapy, chrono-chemotherapy combined with IMRT didn′t affect long-term survival, but reducing the incidence of adverse events in patients with locally advanced NPC.