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1.
Chinese Journal of Stomatology ; (12): 442-450, 2023.
Article in Chinese | WPRIM | ID: wpr-986092

ABSTRACT

Objective: Single-cell RNA sequencing (scRNA-seq) was used to analyze the developing mouse molars, in order to construct a spatiotemporal development atlas of pulp cells, and further to reveal the developmental process and regulatory mechanism of tooth development. Methods: Ten mandibular first molars from C57BL/6 mice in postnatal day (PN) 0 and 3 were respectively dissected and digested to obtain single-cell suspensions. scRNA-seq was performed on 10× Genomics platform. PN 7 mouse molar scRNA-seq data were obtained from our previous study. PN 0, 3, and 7 scRNA-seq data were integrated for following analysis. The initial quality control, mapping and single cell expression matrix construction were performed by Cell Ranger. Quality control, standardization, dimensional reduction and cluster analysis were performed by using Seurat. Monocle was used to generate the pseudotime trajectory. Scillus was used to perform gene ontology analysis. In order to detect the spatiotemporal change of different population of pulp cells, the marker genes of each cluster were demonstrated by RNAscope in situ hybridization. Results: There were twenty-six cell clusters within mouse molars, which were identified as eight different cell types, including dental pulp cells, dental follicle cells, epithelial cells, immune cells, endothelial cells, perivascular cells, glial cells and erythrocytes. We further re-clustered and analyzed dental pulp cells. Cluster 0 were mature pulp cells, which located at the upper portion of crown. The main functions of cluster 0 were osteogenesis and extracellular structure organization. Cluster 1 were apical papilla cells, which located at the apical part of roots, whose main functions were extracellular structure organization and organ development. Cluster 2 were cycling cells, which were actively proliferated, resided in the lower portion of the crown. Cluster 3 and 4 were preodontoblasts and odontoblasts, respectively. Their functions were closely related to biomineralization. The proportion of mature pulp cells increased with the development process, while the proportion of cycling cells and odontoblast lineage decreased. According to the expression pattern of marker genes of each cluster, we constructed a cell atlas of dental pulp. Pseudotime trajectory analysis found there were two development trajectories within dental pulp. They both started from SPARC related modular calcium binding 2 (Smoc2)+ dental papilla cells, then went through DNA topoisomerase Ⅱ alpha (Top2a)+ cycling cells, and finally divided into coxsackie virus and adenovirus receptor (Cxadr)+ mature pulp cells or dentin sialophosphoprotein (Dspp)+ odontoblasts two lineages. Conclusions: scRNA-seq could fully discover the intercellular heterogeneity of cells on transcriptome level, which provides a powerful tool to study the process and regulatory mechanism of organ development.

2.
Chinese Journal of Radiation Oncology ; (6): 333-338, 2023.
Article in Chinese | WPRIM | ID: wpr-993196

ABSTRACT

Objective:To evaluate the usability of Gafchromic HD-V2 film for dose dosimetry in the ultra-high dose-rate (UD) electron beam from a modified medical linac, and to investigate the response between the energy and dose-rate dependence to the film.Methods:The HD-V2 film was utilized to measure the average dose-rate of the UD electron beam. The measured result was compared with those by advanced Markus chamber and alanine pellets. And characteristics of the UD electron beam were also measured by HD-V2 film. Energy dependence of HD-V2 film at three beam energies (6 MV X-ray, 9 MeV and 16 MeV electron beam) was investigated by obtaining and comparing the calibration curves based on the clinical linear accelerator in the dose range of 10-300 Gy. The dose-rate dependence of HD-V2 film was also studied by varying the dose rate among 0.03 Gy/s, 0.06 Gy/s and 0.1 Gy/s, and range of 100-200 Gy/s.Results:The measured average maximum dose-rate of 9 MeV UD electron beam at source skin distance (SSD) 100 cm was approximately 121 Gy/s using HD-V2 film, consistent with the results by advanced Markus chamber and alanine pellets. The measured percentage depth dose (PDD) curve parameters of the UD electron beam were similar to the conventional 9 MeV beam. The off-axis dose distribution of the UD electron beam showed the highest central axis, and the dose was gradually decreased with the increase of off-axis distance. The energy dependence of HD-V2 film had no dependency of 6 MV and 9, 16 MeV while measuring the dose in the range from 20 to 300 Gy. The HD-V2 film had no significant dose-rate dependency at the dose rate of 0.03 Gy/s, 0.06 Gy/s and 0.1 Gy/s for the clinical linear accelerator. Likewise, there was also no dose-rate dependence in the range 100-200 Gy/s in the modified machine.Conclusion:HD-V2 film is suitable for measuring ultra-high dose rate electron beam, independent of energy and dose rate.

3.
Chinese Journal of Radiological Medicine and Protection ; (12): 161-167, 2023.
Article in Chinese | WPRIM | ID: wpr-993068

ABSTRACT

Objective:To compare the effects on DNA strand break induced by ultra-high dose rate (FLASH) electron beam and conventional irradiation, and investigate whether FLASH effect was correlated with a reduction of radiation response.Methods:Aqueous pBR322 plasmid was treated with FLASH (125 Gy/s) and conventional irradiation (0.05 Gy/s) under physioxia (4% O 2) and normoxia (21% O 2). Open circle DNA and linear DNA were detected by agarose gel electrophoresis, and the plasmid DNA damage was quantified with an established mathematical model to calculate the relative biological effect (RBE) of DNA damage. In some experiments, Samwirin A (SW) was applied to scavenge free radicals generated by ionizing radiation. Results:Under physioxia, the yields of DNA strand breakage induced by both FLASH and conventional irradiation had a dose-dependent manner. FLASH irradiation could significantly decrease radiation-induced linear DNA compared with conventional irradiation ( t=5.28, 5.79, 7.01, 7.66, P<0.05). However, when the aqueous plasmid was pretreated with SW, there was no difference of DNA strand breakage between FLASH and conventional irradiation ( P>0.05). Both of the yields of open circle DNA and linear DNA had no difference caused by FLASH and conventional radiotherapy at normoxia, but were significantly higher than those under physioxia. In addition, the yields of linear DNA and open circle DNA induced by FLASH irradiation per Gy were (2.78±0.03) and (1.85±0.17) times higher than those of conventional irradiation, respectively. Conclusions:FLASH irradiation attenuated radiation-induced DNA damage since a low production yield of free radical in comparison with conventional irradiation, and hence the FLASH effect was correlated with oxygen content.

4.
Chinese Journal of Radiological Medicine and Protection ; (12): 87-93, 2023.
Article in Chinese | WPRIM | ID: wpr-993056

ABSTRACT

Objective:To investigate the prognostic value of metabolic parameters of 18F-fluorodeoxyglucose ( 18F-FDG) positron emission computed tomography/computed tomography(PET/CT) in advanced non-small cell lung cancer(NSCLC) treated with first-line immune checkpoint inhibitor (ICI) combined with chemotherapy. Methods:A retrospective study was conducted to evaluate patients with advanced NSCLC who underwent baseline PET/CT before treatment at the Affiliated Cancer Hospital of Zhengzhou University from 2019 to 2021. Receiver operating characteristic (ROC) curve analysis was used to determine the cut-offs for metabolic parameters of PET/CT, including total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), and maximum standard uptake value (SUV max). Kaplan-Meier method, Log-rank test, and Cox regression model were used to calculate the overall survival (OS) and the progression-free survival(PFS). Results:A total of 44 patients were enrolled. Univariate analysis showed that the factors influencing PFS were TMTV and the number of metastatic sites ( χ2=4.19, 11.28, P<0.05) and the factors influencing OS were TMTV and TLG ( χ2=14.96, 6.05, P<0.05). Multivariate analysis suggested that number of metastatic sites was an independent prognostic marker for PFS ( P=0.011) and TMTV was an independent prognostic marker for OS ( P=0.038). Conclusions:TMTV is a prognostic indicator of OS while the number of metastatic sites is a prognostic indicator of PFS in advanced NSCLC patients who received first-line ICI combined with chemotherapy, but further prospective studies are needed.

5.
Chinese Journal of Radiation Oncology ; (6): 519-524, 2022.
Article in Chinese | WPRIM | ID: wpr-932699

ABSTRACT

Objective:To analyze the failure patterns and influencing factors of stereotactic ablative radiotherapy (SABR) for early-stage non-small cell lung cancer (ES-NSCLC).Methods:113 cases of ES-NSCLC treated with SABR from 2012 to 2020 in our hospital were retrospectively analyzed. The failure patterns, recurrence time, recurrence site and influencing factors were analyzed. Kaplan-Meier method was used to calculate the local recurrence rate, regional lymph node recurrence rate and distant metastasis rate. Univariate analysis was performed by Log-rank test, and multivariate analysis was performed by Cox model.Results:The median follow-up time was 58 months (range: 6-108 months), and a total of 45 patients (39.8%) recurred. The median recurrence time was 36 months. Distant metastasis (DM) occurred in 31 patients (27.4%) and DM alone in 24 patients (21.2%). Local recurrence (LR) was developed in 12 patients (10.6%) and LR alone in 7(6.2%). Regional lymph node recurrence (RR) occurred in 11 patients (9.7%) and RR alone in 6 patients (5.3%). LR combined with RR was observed in 1 case (0.9%), LR combined with DM in 3(2.7%), LR combined with RR and DM in 1(0.9%), and RR combined with DM in 3(2.7%). The 1-, 2-, 3-, 4-and 5-year recurrence rates were 5.4%, 16.6%, 27.5%, 44% and 51.2%, respectively. Univariate and multivariate analyses suggested that EGFR mutation was an influencing factor of high recurrence rate.Conclusion:ES-NSCLC patients treated with SABR alone have a high recurrence rate, and DM is the most common mode of failure. Follow-up consolidation therapy is recommended, especially for EGFR mutation-positive NSCLC patients.

6.
Chinese Journal of Radiation Oncology ; (6): 49-54, 2022.
Article in Chinese | WPRIM | ID: wpr-932627

ABSTRACT

Objective:To propose an automatic planning approach for Eclipse15.6 planning system based on Eclipse scripting application programming interface (ESAPI) and evaluate its clinical application.Methods:20 patients with nasopharyngeal carcinoma and 20 cases of rectal cancer were selected in the clinical planning. The developed automatic planning script SmartPlan and RapidPlan were used for automatic planning and dosimetric parameters were compared with manual planning. The differences were compared between two groups by using Wilcoxon signed rank test. Results:The dosimetric results of automatic and manual plans could meet clinical requirements. There was no significant difference in target coverage in nasopharyngeal carcinoma planning between two groups ( P>0.05), and automatic plans were superior to manual plans in organs at risk sparing ( P<0.05). Except for the homogeneity index of PTV and the maximum dose of bowel in rectal cancer plans, the other dosimetric parameters of the automatic plans were better than those of the manual plans (all P<0.05). Conclusions:Compared with the manual plans, the automatic plans have the same or similar target coverage, similar or better protection of organs at risk, and more convenient implementation. The developed SmartPlan based on ESAPI has clinical feasibility and effectiveness.

7.
Chinese Journal of Radiation Oncology ; (6): 1022-1027, 2022.
Article in Chinese | WPRIM | ID: wpr-956947

ABSTRACT

Objective:To investigate the feasibility of transforming conventional medical accelerator to achieve ultra-high dose rate required to achieve Flash radiotherapy (Flash-RT), and to understand the physical properties of the Flash-RT beam.Methods:By transforming the Varian 23CX medical accelerator, the radiation average dose rate at the isocenter was not less than 40 Gy/s. The relevant physical measurement scheme was designed to accurately measure the actual radiation dose rate of different source skin distance (SSD) conditions, the percent depth dose (PDD) curve and the off-axis dose distribution of the beam.Results:The average dose rate of 9 MeV electron beam after the transformation was measured using the HD-V2 type film, the average dose rate of 3 s was 97.9 Gy/s, and the average dose rate of 6 s was 99.27 Gy/s. When the SSD was 100 cm, 80 cm and 60 cm, the average dose rate of 9 MeV electron beam after the transformation was 99.3 Gy/s, 168 Gy/s and 297.5 Gy/s, respectively. After the transformation, the R100 of the 9 MeV beam was 2.2 cm underwater, R50 was 3.87 cm underwater, the electron range Rp was 4.58 cm, and the maximum possible energy Ep,0 on the phantom surface was 9.28 MeV. These parameters were slightly higher than those of the conventional 9 MeV beam, manifested with slight increase in the surface dose and widening high dose flat area. The overall deposit dose distribution exhibited the highest central axis and the increase in dose declines from the axis distance. Under the condition that the field size was 20 cm×20 cm and the SSD was 100 cm, the FWHM of the vertical and horizontal off-axis dose distribution curves were 16.6 cm and 16.4 cm, respectively. Conclusion:By transforming conventional medical accelerator, the average dose rate of the beam at the isocycle meets the requirement of Flash-RT, and the average dose rate under the condition of 60 cm SSD is much higher than the requirement of at least 40 Gy/s for Flash-RT.

8.
Chinese Journal of Radiation Oncology ; (6): 1004-1010, 2022.
Article in Chinese | WPRIM | ID: wpr-956944

ABSTRACT

Objective:To analyze the clinical efficacy of different treatment modalities and prognostic factors of patients with Masaoka-Koga stage Ⅲ thymoma.Methods:Clinical data of patients diagnosed with Masaoka-Koga stage Ⅲ thymoma admitted to Affiliated Cancer Hospital of Zhengzhou University from January 2000 to December 2018 were analyzed retrospectively. A total of 133 patients had complete treatment and follow-up data. Kaplan-Meier method was used to calculate the cumulative survival rate, log-rank method was used to compare the survival between two groups, and Cox regression model was used for multivariate analysis.Results:The median follow-up time was 50 months (3-221 months). The median overall survival (OS) was 51 (3-221) months, and the median disease-free survival (DFS) was 45 (2-221) months. The survival rate in the radical surgery group was better than that in the palliative surgery group. The 5- and 10-year OS rates in radical surgery group were 88.2% and 74.4% respectively, while in palliative surgery group were 51.8% and 32.4% respectively ( P<0.001). The 5- and 10-year DFS rates in radical surgery group were 72.2% and 45.5%, respectively, while in palliative surgery group were 32.3% and 16.1% respectively ( P=0.001). The OS in the surgery combined with radiotherapy group was better than that in the surgery alone group. The 5- and 10-year OS rates in the radical surgery group were 82.8% and 64.2% respectively, while in the palliative surgery group were 55.8% and 50.2% ( P=0.033). There was no significant difference in DFS between two groups ( P=0.176). Multivariate analysis showed that age < 50 years old ( HR=0.264, P=0.001), radical resection ( HR=0.134, P<0.001), surgery combined with radiotherapy ( HR=2.778, P=0.009) were independently associated with better OS. Age < 50 years old ( HR=0.550, P=0.046), radical resection ( HR=0.555, P=0.042), and invasion of single organ ( HR=0.111, P=0.003) were independently associated with better DFS. Conclusions:OS and DFS in patients undergoing radical surgery are significantly better than those in their counterparts treated with palliative surgery, which is the most important factor affecting prognosis. Surgery combined with radiotherapy yields better OS. It is necessary to design a rigorous and reasonable multicenter prospective study to evaluate the efficacy of various treatment modalities and prognostic factors.

9.
Chinese Journal of Radiation Oncology ; (6): 949-954, 2022.
Article in Chinese | WPRIM | ID: wpr-956938

ABSTRACT

Esophageal squamous cell carcinoma is one of the most common malignant tumors in China. Neoadjuvant chemoradiotherapy combined with surgery significantly improved the survival rate of locally advanced operable esophageal squamous cell carcinoma, but approximately half of the patients had poor or no efficacy. To accurately predict the efficacy of neoadjuvant chemoradiotherapy in patients with esophageal squamous cell carcinoma and select the dominant population of neoadjuvant chemoradiotherapy, many studies on biomarkers have emerged, which have promoted the progress of neoadjuvant therapy for esophageal squamous cell carcinoma to some extent. In this article, the studies on biomarkers predicting the efficacy of neoadjuvant chemoradiotherapy in esophageal squamous cell carcinoma were reviewed.

10.
Chinese Journal of Radiation Oncology ; (6): 843-847, 2022.
Article in Chinese | WPRIM | ID: wpr-956922

ABSTRACT

In recent years, the application of immune checkpoint inhibitors (PD-1/PD-L1/CTLA-4, etc.) in the treatment of non-small cell lung cancer (NSCLC) has developed rapidly. However, the response rate of immune checkpoint inhibitors alone is as low as 15%-30%. There are still many problems in clinical practice, such as limited benefit population, lack of effective biomarkers and treatment resistance, etc. Compared with conventional fractionated radiotherapy, stereotactic body radiation therapy (SBRT) has the characteristics of higher single dose, less irradiation times and stronger immune activation ability. It has shown good anti-tumor effect in patients with advanced NSCLC oligometastasis. The combination of immune checkpoint inhibitors and SBRT is the development trend of tumor therapy. Preclinical and clinical studies show that SBRT can enhance the efficacy of immunotherapy in patients with NSCLC. In the initial study, single-lesion SBRT was first recommended to reduce potential toxicity. However, more and more studies have confirmed the feasibility and necessity of multi-lesion SBRT. In this review, we not only elucidated the mechanism and the latest progress upon combined use of SBRT and immune checkpoint inhibitors in advanced NSCLC oligometastasis, but also explored the basic and clinical research of multi-lesion SBRT combined with immunotherapy, aiming to guide clinical practice.

11.
Chinese Journal of Radiological Medicine and Protection ; (12): 738-744, 2022.
Article in Chinese | WPRIM | ID: wpr-956854

ABSTRACT

Objective:To analyze the data of ultra-high dose rate (FLASH) radiotherapy in GEO (Gene Expression Omnibus) database by bioinformatics method, in order to find the hub genes involved in flash radiotherapy induced acute T-lymphoblastic leukemia.Methods:The gene expression profiles of malignant tumors receiving FLASH radiotherapy were downloaded from GEO database. The R software was used to screen the differential expressed genes (DEGs) and analyze their biological functions and signal pathways. The protein-protein interaction (PPI) network of DEGs was analyzed by online tool of STRING, and Hub genes were screened by Cytoscape plug-in. The expressions of screened Hub genes in acute T lymphoblastic leukemia were identified with TCGA (The Cancer Genome Atlas) and GTEx (Genotype-Tissue Expression) database.Results:Based on the analysis of GSE100718 microarray dataset of GEO database, a total of 12 800 genes were found to be associated with radiosensitivity of acute T lymphoblastic leukemia, of which 61 significantly altered DEGs were selected for further analysis. It was found that these genes were involved in the biological processes of metabolism, stress response, and immune response through the pathways of oxidative phosphorylation, unfolded protein response, fatty acid metabolism, and so on. PPI analysis indicated that HSPA5 and SCD belonged to the Hub genes involved in the regulation of FLASH radiosensitivity, and they were significantly highly expressed in acute T lymphoblastic leukemia combined with TRD/LMO2-fusion gene.Conclusions:Through bioinformatics analysis, the Hub genes involved in regulating the sensitivity of FLASH radiotherapy and conventional radiotherapy can be effectively screened, and thus the gene expression profiles can be used to guide the stratification of cancer patients to achieve a precise radiotherapy.

12.
Chinese Journal of Radiological Medicine and Protection ; (12): 504-510, 2022.
Article in Chinese | WPRIM | ID: wpr-956815

ABSTRACT

Objective:To investigate the relationship between lung immune prognostic index (LIPI) and the prognosis of locally advanced non-small cell lung cancer (LA-NSCLC) treated with radiochemotherapy.Methods:A retrospective analysis was conducted for the clinical data of LA-NSCLC patients who received radiochemotherapy in the Affiliated Cancer Hospital of Zhengzhou University from 2013 to 2019. According to the hematologic test result of the derived neutrophil-to-lymphocyte ratio (dNLR) and the lactate dehydrogenase (LDH), the patients were divided into three groups according to their LIPI scores, namely the good-LIPI group with dNLR ≤ 3 and LDH ≤ upper limit of normal (ULN), moderate-LIPI group with dNLR >3 or LDH > ULN, and poor-LIPI group with dNLR >3 and LDH > ULN. Moreover, the overall survival (OS) and the progression-free survival (PFS) were calculated using the Kaplan-Meier method, the Log-rank test, and the Cox regression model.Results:A total of 238 patients were enrolled, and their median follow-up time was 37.1 months, median PFS 16.1 months, and median OS 30.6 months. The OS and PFS of the poor-LIPI group were significantly worse than those of the good- and moderate-LIPI groups ( χ2= 9.04, 2.88, P<0.05). The univariate analysis showed that the factors influencing OS included gender, pathological type, epidermal growth factor receptor (EGFR) mutations, and LIPI ( χ2=6.10, 13.66, 10.58, 9.04, P<0.05), and the PFS was only affected by the LIPI ( χ2=2.88, P = 0.03). Multivariate analysis suggested that EGFR mutations and LIPI were independent prognostic markers for OS ( HR = 1.31, 1.36; 95% CI: 1.03-1.67, 1.05-1.76; P<0.05). Conclusions:The LIPI is a potential prognostic indicator of radiochemotherapy in LA-NSCLC, and this result should be further confirmed by prospective studies.

13.
Chinese Journal of Radiation Oncology ; (6): 1286-1291, 2021.
Article in Chinese | WPRIM | ID: wpr-910552

ABSTRACT

Objective:To develop a verification platform based on Monte Carlo (MC) for independent dose verification of volumetric modulated arc therapy (VMAT) plans.Methods:The head model including collimator of Varian TrueBeam linear accelerator was constructed by using EGSnrc/BEAMnrc, and the independent dose verification platform for the patients’ VMAT plans was built based on the head model and an in-house code. The percent depth dose (PDD) curves and off-axis ratios for different field sizes, the dose distribution of two irregular fields and three VMAT plans of the head and neck, chest, and pelvis were simulated using the platform. The simulated results of the PDD curves and the off-axis ratios of different field sizes were compared with the blue water measurement results. The difference between the irregular fields and the actual ArcCHECK measurements was also investigated. Besides, the differences among the MC simulated dose, TPS calculated dose and the ArcCHECK measured dose were analyzed by several methods, such as γ analysis and dose-volume histogram to verify whether the platform could be independently employed for dose verification.Results:The MC simulated results of PDD curves and off-axis ratios from 4 cm×4 cm to 40 cm×40 cm were in good agreement with the measured results. And the γ passing rates between the MC simulation and the ArcCHECK measurement for the irregular fields were above 98.1% and 99.1% for 3%/2 mm and 3%/3 mm, respectively. For VMAT plans of three patients, the γ results between the MC simulated dose and ArcCHECK measured dose were better than 93.8% and 95.9% under the criteria of 3%/2 mm and 3%/3 mm respectively. At the same time, the γ passing rates of nasopharyngeal, lung, and rectal cancers were 95.2%, 98.6% and 98.9% based on 3D γ analysis using TPS calculated dose and MC simulated dose under the criteria of 3%/3 mm; the passing rates of these three were 90.3%, 95.1% and 96.7% for 3%/2 mm, respectively.Conclusions:The simulation results of the MC-based verification platform developed in this study show a good agreement with the actual measurement results, and the simulation results are closer to the real dose distribution using the patients’ data. The preliminary results demonstrate that the platform can be used for accurate independent dose verification of VMAT plans.

14.
Chinese Journal of Radiation Oncology ; (6): 1275-1279, 2021.
Article in Chinese | WPRIM | ID: wpr-910550

ABSTRACT

Objective:To propose an automatic planning method of intensity-modulated radiotherapy (IMRT) for esophageal cancer based on dose volume histogram prediction and beam angle optimization in Raystation treatment planning system.Methods:50 IMRT plans of esophageal cancer were selected as the training set to establish a dose prediction model for organs at risk. Another 20 testing plans were optimized in Raystation using RuiPlan and manual method, and the beam angle optimization and dose volume histogram prediction functions of RuiPlan were used for automatic planning. Dosimetric differences and planning efficiency between two methods were statistically compared with paired t-test. Results:There were no significant dosimetric differences in the conformity index (CI), homogeneity index (HI) of PTV, V 5Gy of both lungs and D max of the spinal cord between automatic and manual plans (all P>0.05). Compared with those in the manual plans, the V 20Gy and D mean of the left and right lungs generated from automatic plans were reduced by 1.1%, 0.37 Gy and 1.2%, 0.38 Gy (all P<0.05), and the V 30Gy, V 40Gy and D mean of the heart in automatic plans were significantly decreased by 5.1%, 3.0% and 1.41 Gy, respectively (all P<0.05). The labor time, computer working time, and monitor unit (MU) number of automatic plans were significantly decreased by 65.8%, 14.1%, and 17.2%, respectively (all P<0.05). Conclusion:RuiPlan automatic planning scripts can improve the efficiency of esophageal cancer planning by dose prediction and beam angle optimization, providing an alternative for esophageal cancer radiotherapy planning.

15.
Chinese Journal of Radiation Oncology ; (6): 1178-1182, 2021.
Article in Chinese | WPRIM | ID: wpr-910534

ABSTRACT

Objective:To build a systemic and automatic importing scheme for importing CT images and structures into the treatment planning systems (TPSs) of Eclipse and Monaco.Methods:Based on two TPSs of Eclipse and Monaco, the files of CT images and structures were automatically transported from OAR auto-delineation system to the importing directory of these two TPSs using batch script in Windows system. Following the standard importing procedures of these two TPSs, the automatically importing script of CT images and structures were developed using the application of UiBot. Finally, the CT images and structures were imported into these two TPSs opportunely.Results:By comparing the importing time using script and manual methods, the script not only achieved auto-importing CT images and structures into TPSs, but also yielded almost the same efficiency to manual method. The number of imaging layers in most patients was between 130 and 180, and the average manual and automatic importing time within this interval was 76 s and 75 s.Conclusions:Automatic scripts can be developed by using the automation function of UiBot combined with the actual problems of radiotherapy and repeated workflow. The efficiency of radiotherapy work can be significantly improved. Manual and time costs can be saved. It provides a novel alternative for the automation of radiotherapy procedures.

16.
Chinese Journal of Radiation Oncology ; (6): 1065-1070, 2021.
Article in Chinese | WPRIM | ID: wpr-910515

ABSTRACT

Objective:To validate the accuracy of physical model of in-vivo 3D dose verification based on electronic portal imaging device (EPID) using the phantom and preliminarily analyze the clinical application.Methods:Two phantoms (uniform and non-uniform phantoms) were involved in this study. The system of in-vivo 3D dose verification based on EPID was employed to acquire the images of square fields (SF) and combined fields of intensity-modulated radiotherapy (CFIMRT). The physical model of different media was constructed using the system. The factor of γ passing rate under different dose/distance criteria was statistically compared. For clinical cases, the dose-volume histograms were adopted to analyze the dose distribution of target volume and organs at risk (OARs).Results:For the SF in the uniform phantom, the average γ passing rate (3%/3 mm) was (97.49±1.11)%, and (94.06±5.11)% for the SF in the non-uniform phantom ( P>0.05). No statistical significance was noted in IMRT using different delivery methods (all P>0.05). For clinical cases, the average γ passing rate (3%/2 mm) was (97.96±1.84)% in the pre-treatment dose verification, and (90.51±6.96)%(3%/3 mm) for the in-vivo 3D dose verification. For clinical cases, significant dose deviation was observed in OARs with small size and large volume changes. Conclusion:The in-vivo 3D dose verification model based on EPID can be effectively applied in inter-fraction dose verification, providing technical support for adaptive radiotherapy in clinical practice.

17.
Chinese Journal of Radiation Oncology ; (6): 676-681, 2021.
Article in Chinese | WPRIM | ID: wpr-910448

ABSTRACT

Objective:To explore the value of BLADE sequence in determining the target range of esophageal cancer radiotherapy through the correlation and consistency between measured esophageal cancer length on the MRI-BLADE sequence and the surgical pathological specimens.Methods:Clinical data of 36 patients who were pathologically diagnosed with esophageal carcinoma and received preoperative esophageal MRI in the Affiliated Cancer Hospital of Zhengzhou University between January 2016 to June 2019 were collected. The CT, DWI and BLADE sequence images of all participants were collected and imported into the Monaco system, by which the correlation and consistency between the tumor length measured based on these three imaging methods were statistically compared. Furthermore, the differences in gross tumor volume (GTV) delineated by different physicians in different images were compared.Results:The correlation coefficients of the tumor length measured by CT, DWI and BLADE and pathological specimen length were 0.467, 0.723 and 0.896, respectively. The consistency analysis indicated that all the differences between the BLADE sequence and pathological specimen length were within the 95% consistency limit. The consistency and correlation between the BLADE sequence and actual tumor length were significantly better than those between the DWI sequence and CT images (both P<0.05). The volume of DWI and BLADE images obtained by four physicians was significantly smaller than that of CT images (both P<0.05). The differences in GTV delineated by different physicians by these three imaging methods were insignificant (all P>0.05), but the GTV delineated by the four physicians on the BLADE sequence were more similar (all P>0.05). Conclusions:BLADE sequence can help physicians to determine the upper and lower boundaries of esophageal tumors more accurately and reduce the differences in GTV delineation among different physicians. And it can effectively improve the unity of individual′s understanding of the scope of target area delineation, and improve the objectivity of clinicians′ judgment of GTV. BLADE sequence can be used as an important imaging tool for accurate target delineation in radiotherapy.

18.
Chinese Journal of Radiological Medicine and Protection ; (12): 636-640, 2021.
Article in Chinese | WPRIM | ID: wpr-910369

ABSTRACT

As a method for local treatment, radiotherapy plays a key role in the management of tumors. In the past few decades, great progress has been made in radiotherapy technology, with improvements in conformity, homogeneity, and radiotherapy efficiency, and the results are encouraging. Nevertheless, the maximum tolerated dose of normal tissue has limited the further increase in radiotherapy dose in the tumor area. If radiation-induced toxicities can be reduced, a higher radiotherapy dose can be delivered to tumor tissue, so as to achieve a better treatment response. In recent years, the unique FLASH effect of ultra-high-dose-rate radiotherapy (FLASH-RT) is capable of maintaining a consistent tumor response whilst reducing radiation-induced toxicities in normal tissue, and therefore, FLASH-RT has become a research hotspot in the field of radiotherapy across the world. At present, some scholars tend to explain the FLASH effect using the theory of acute oxygen depletion, but the protective effect of FLASH-RT on normal tissue remains to be clarified. In addition, preliminary clinical studies have been conducted for FLASH-RT, and the results are promising. Based on existing evidence, this article elaborates on the research advances in FLASH-RT in the treatment of malignant tumor, so as to provide a reference for the translation and application of this new technique.

19.
Chinese Journal of Radiological Medicine and Protection ; (12): 340-345, 2021.
Article in Chinese | WPRIM | ID: wpr-910318

ABSTRACT

Objective:To explore a new technology that can protect the lungs and heart better by utilizing the dose distribution attributes of the half-field and the characteristics of the VMAT (volumetric modulated arc therapy) technology.Methods:A three-dimensional water tank was used to measure the dose of symmetrical field and half field edge and analyze them comparatively. A total of 50 patients with left breast cancer receiving the postoperative radiotherapy were selected. Among them, 25 patients were performed conserving surgery and 25 patients were performed radical mastectomy. After the operation, all the patients received the prescription dose of 50 Gy in 25 fractions. Based on the Eclipse system, the symmetrical field continuous arc VMAT technology and the semi-field segmented arc VMAT technology were used to design the plan. Besides, the dose suitability data and the treatment efficiency of target areas and organs at risk were compared and analyzed.Results:The radiation size of half-field did not increase with the increased depth in the water mode. The symmetric field gradually enlarged due to the angle of tensor factor, increased to about 2 cm at the depth of 30 cm, and the delivery dose in the half-field was lower than that in the symmetric field. The closer the field edge is, the more obvious it is. Compared with the symmetric field continuous arc plan, the half-field segmental arc VMAT plan significantly improved the delivery dose of the lungs and heart ( t=-4.11, -4.42, P=0.00), in which the mean values of V5, V30, and Dmean for the whole structure of the heart were reduced by 52.5%, 65.5%, and 47%, respectively. The left anterior descending coronary artery, which was closely related to the target area, had a decrease of more than 20%. The mean values of V5, V10, V20, and Dmean of the affected lung were reduced by 21.6%, 24.8%, 25.0%, and 23.2%, respectively. The mean values of the doses of other endangered healthy organs, and the execution time of half-field segment arc plan were also better than the continuous arc plan. Conclusions:For breast cancer radiotherapy, the combination of half-field and VMAT can give full play to the advantages of half-field and VMAT, and significantly reduce the irradiated dose of the heart, affected lung, and healthy side of the breast.

20.
Cancer Research on Prevention and Treatment ; (12): 958-962, 2021.
Article in Chinese | WPRIM | ID: wpr-988478

ABSTRACT

Objective To investigate the correlation between cyclin G1 expression and the efficacy of radiotherapy on HCC. Methods The expression of cyclin G1 in biopsy specimens of 68 patients who received radiotherapy was detected by immunochemistry. The correlation between cyclin G1 expression and clinicopathological characteristics was analyzed by chi-square test. The correlation between cyclin G1 expression and OS or PFS was evaluated by Kaplan-Meier analysis. Univariate and multivariate analyses were used for the relation between clinicopathological characteristics and OS or PFS. Results The expression of cyclin G1 was related to portal vein tumor embolus, clinical stage and alpha fetoprotein. Survival analysis showed that the OS and PFS of patients with low expression of cyclin G1 were significantly higher than those with high cyclin G1 expression (P < 0.05). Multivariate analysis showed that cyclin G1 was an independent risk factor for DFS of patients with HCC. Conclusion High expression of cyclin G1 is an adverse prognostic factor for HCC patients who received radiotherapy.

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