ABSTRACT
At present,precise radiotherapy has been widely used through the development with many years,but the existing technique still is limited by the limitation of tolerance dose of normal tissues,which cannot achieve the optimal goal of treating tumor.Flash radiotherapy(Flash-RT)is one kind of radiotherapy technique that uses the beam with ultra-high dose rate(UHDR)to conduct irradiation,which can furthest treat tumors while significantly reduce radiation injury of normal tissues.But until now,the biological mechanism,key physical parameters and triggering mechanism of Flash-RT are still unclear,and its principle and clinical translational application are still in the stage of research.This review clarified the technological advance and clinical translational application of Flash-RT research through summarized the relevant research of Flash-RT.
ABSTRACT
The Flash radiotherapy(Flash-RT),which is the key breakthrough in the basic field of radiotherapy technique,which is expected to cause a new major transformation in the field of radiotherapy.In this paper,we reviewed the latest research advances of the application and the mechanism exploration of Flash-RT in tumor treatment.Current studies have found that both the Flash-RT with electron beams and photon and the Flash-RT with proton can reduce injury of normal tissue than radiotherapy with conventional dose-rate,but the relevant mechanisms are not yet clearly understood,which includes but not limited to oxygen depletion,DNA damage,cellular senescence,apoptosis and immune response.The difference of Flash-RT injury between tumor tissue and normal tissue further reduces the limitations of radiotherapy,and reduces the adverse reaction and complication compared with conventional radiotherapy,which has wide application prospects.
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Objective:To explore the regulatory effect of glutathione S-transferase P1(GSTP1) on the radiosensitivity of mouse Lewis lung cancer (LLC) cells.Methods:GSTP1-shRNA lentivirus and negative control lentivirus were used to respectively infect the LLC cells, and stable transgenic strains were selected. Real-time PCR and Western blot were conducted to quantitatively measure the expression levels of GSTP1 mRNA and protein in the LLC cells to verify the knockdown effect. The cell counting kit-8(CCK-8) assay was used to detect cell viability after irradiation. The colony formation assay was utilized to assess the cell proliferation ability after irradiation. Flow cytometry was performed to assess the level of cell apoptosis after irradiation. The tumor-bearing mice were established and irradiated to detect the changes in the tumor volume after irradiation. TUNEL staining was employed to detect the level of tumor apoptosis after irradiation. Immunofluorescence was used to detect the number of CD 4+ CD 8+ T cells in the tumor after irradiation. Results:Real-time PCR and Western blot showed that after shRNA lentivirus interference, the expression levels of GSTP1 mRNA and protein were significantly down-regulated. Down-regulation of GSTP1 reduced cell viability and proliferation, and increased the rate of cell apoptosis after irradiation. The tumor volume of the tumor-bearing mice after irradiation in the GSTP1 knockdown group was significantly smaller than that in the NC group, whereas the tumor apoptosis rate was significantly higher and the number of infiltrating CD 4+ CD 8+ T cells in the tumor was remarkably higher compared with those in the control group. Conclusion:Knockdown of GSTP1 can significantly increase the radiosensitivity of LLC cells and enhance the infiltration of lymphocytes in tumor tissues.
ABSTRACT
The segmentation of organs at risk is an important part of radiotherapy. The current method of manual segmentation depends on the knowledge and experience of physicians, which is very time-consuming and difficult to ensure the accuracy, consistency and repeatability. Therefore, a deep convolutional neural network (DCNN) is proposed for the automatic and accurate segmentation of head and neck organs at risk. The data of 496 patients with nasopharyngeal carcinoma were reviewed. Among them, 376 cases were randomly selected for training set, 60 cases for validation set and 60 cases for test set. Using the three-dimensional (3D) U-NET DCNN, combined with two loss functions of Dice Loss and Generalized Dice Loss, the automatic segmentation neural network model for the head and neck organs at risk was trained. The evaluation parameters are Dice similarity coefficient and Jaccard distance. The average Dice Similarity coefficient of the 19 organs at risk was 0.91, and the Jaccard distance was 0.15. The results demonstrate that 3D U-NET DCNN combined with Dice Loss function can be better applied to automatic segmentation of head and neck organs at risk.
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Objective To investigate the association and mechanism between glutathione S-transferase P1(GSTP1) and radiation-induced lung injury.Methods Two effective GSTP1 siRNAs were designed and synthesized.The normal lung epithelial cell line BEAS-2B cells were transfected with GSTP1 siRNA (experimental group,siRNA-1,siRNA-2) and negative control siRNA (negative control group,NC).Western blot was performed to detect the expression levels of GSTP1 protein and EMT-related proteins.CDNB was adopted to evaluate the activity of GSTs.DCFH-DA probe was used for incubation.Flow cytometry was conducted to detect the median fluorescence intensity (MFI) and cellular apoptosis.Annexin-v/PI staining was utilized for incubation.MTT assay was performed to measure the proliferation of BEAS-2B,and the growth curve was drawn based on the results.Results After radiation,compared with the NC group,the ROS level and MFI were significantly higher in experimental group (6774.66±399.60 vs.8759.00±256.96 vs.9967.67±735.11,P<0.05).In the experimental group,the percentage of cellular apoptosis was remarkably higher than that in the NC group (12.3± 1.16 vs.17.38± 1.65 vs.22.88± 1.20,P<0.05).MTT assay demonstrated that the OD values in the experimental group were significantly lower than that in the NC group everyday.Further more,the level of EMT process is higher in the experimental group.Conclusions Interfering with the GSTP1 expression in lung epithelial cells can increase the intracellular ROS level,increase the percentage of cellular apoptosis,and reduce the cell proliferation rate following γ-radiation.Besides,it can also promote the epithelial mesenchymal transition in lung epithelial cells.The down-regulation of GSTP1 protein expression level probably aggravates the radiationinduced lung cell injury and promotes the epithelial mesenchymal transition.
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Objective To develop the information management system in the Department of Radiotherapy,optimize the procedures of radiotherapy, realize the informatization of radiotherapy process management and improve medical efficiency. Methods Multi-digital template was adopted to integrate the information of cancer treatment. The server was equipped with multi-terminal mode to establish the information management system of radiotherapy process. The work authority was assigned according to different positions. The system was connected with radiotherapy plan system (TPS),hospital information system (HIS) and picture archiving and communication system (PACS) to realize the information collection, recording charges, information transmission and plan evaluation and audit in Department of Radiotherapy. Results The information management system optimized the radiotherapy procedures,strengthened connection among different systems, linked the information systems among different departments, standardized the radiotherapy procedures and enhanced the clinical efficiency. Conclusions The application of information management system improves the management level of radiotherapy process, establish a unified standard for cancer treatment and provide complete management plans for the radiotherapy process and quality control. It is a unique and prospective system,which is advantageous in the management of treatment process,systematization of information collection and quality control.
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Objective To assess the effectiveness of the combined treatment model for Wilms'tumor and to improve treatment results.Methods Fifty-five patients diagnosed with Wilms' tumor between July 1981 to June 2010 were analyzed retrospectively.Eighteen patients were diagnosed by preoperative ultrasound-guided fine needle biopsy,and 53 patients were confirmed by postoperative pathology results.Seven cases were in clinical stage Ⅰ,19 cases in clinical stage Ⅱ,21 cases in stage Ⅲ,six cases in stage Ⅳ and two cases in stage Ⅴ.Thirty-five cases had histopathological subtype,30 cases had the favorable type,and five cases had the unfavorable type.Among the 55 patients,kidney tumor resection was performed on 48 cases,wide edge partial nephrectomy was performed on two cases,tumor enucleation was performed on one bilateral renal tumor case,kidney tumor resection with pulmonary metastasectomy was performed on two cases,and two cases had no surgical procedures.Eighteen cases received preoperative chemotherapy,40 cases received postoperative chemotherapy,and 12 cases received postoperative radiotherapy.Patients were grouped according to age,stage,histological type,treatment model,treatment course and whether or not they had radiotherapy.The Kaplan-Meier method was used in the evaluation and comparison of over survival (OS),disease free survival (DFS) and relapse free survival (RFS) of the different groups to reveal the relationship between different grouping factors with the prognosis of Wilms' tumor. ResultsThe median of follow-up was 34 mon ( ranging from 3 to 355 mon).The 3-year OS,5-year OS and 2-year DFS were 77.6%,69.0% and 52.4%,respectively.The differences of OS in different stages ( P =0.006 ),DFS between pure operation group and combined therapy group ( P =0.004 ) and RFS between radiotherapy group and no radiotherapy group ( P =0.03 ) were significant,P < 0.05.ConclusionsThe normative multi-disciplinary treatment model for patients with Wilms' tumor can achieve good results and is well tolerated.
ABSTRACT
Magnetic nanoparticle will become a kind of mean and colloidal solution if it is coated with surfacant.Magnetic nanoparticle has a wide clinical practice because it can produce heat in alternating magnetic fields,especially in malignant tumors thearapy.Magnetic nanoparticle hyperthermia,nano-delivery and magnetic target drug,and intravascular embolization with magnetic particle will bring new hope for tumor patients.