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OBJECTIVE To explore the effects of 5，10-methylenetetetrahydrofolate reductase （MTHFR） gene polymorphism on the adverse reactions in patients with osteosarcoma after the first high-dose methotrexate （HD-MTX） treatment. METHODS A prospective study was conducted to include 53 patients with osteosarcoma treated with HD-MTX at the first admission in General Hospital of Eastern Theater Command. The dose of MTX was evaluated according to the polymorphism of rs1801133 in the METHFR gene and demographic factors， then whole pharmaceutical monitoring was conducted. The data on liver toxicity， renal toxicity， hematological toxicity， and gastrointestinal reaction were collected after the first chemotherapy cycle. Single factor analysis and binary Logistic regression analysis were used to analyze the correlation between MTX dose， 24 h blood drug concentration， and rs1801133 locus genotype with four adverse reactions. RESULTS The MTX dosage in patients with CC wild type was significantly higher than that in TT mutant type （7.97 g/m2 vs. 6.98 g/m2， P＝0.030）， but this difference did not affect the 0 h and 24 h blood drug concentrations of MTX. The above four adverse reactions were not related to the dose of MTX. The results of binary Logistic regression analysis showed that carrying one T allele increased the risk of developing hematological toxicity by 4.13 times（95% confidence interval：1.35-12.62，P＝0.013）. When 24 h plasma concentration threshold of MTX was set to 2.65 µmol/L， the sensitivity and specificity of predicting liver function damage were 53.33% and 86.96%， respectively； when the threshold was set to 7.28 μmol/L， the sensitivity and specificity of predicting renal damage were 100% and 81.63%. CONCLUSIONS The polymorphism of the rs1801133 in the MTHFR gene is associated with hematological toxicity of MTX. Patients who take HD-MTX for the first time and carry the T allele have a high risk of hematological toxicity. The 24 h plasma concentration of MTX is related to liver toxicity and renal toxicity. In addition， monitoring the 24 h blood drug concentration can predict liver and renal toxicity， and take early intervention.
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Man in his 70s, who had suffered from idiopathic thrombocytopenic purpura (ITP), was admitted to our hospital with chest pain at rest. Coronary angiography revealed obstruction of the right coronary artery and triple vessel disease. Because a bleeding tendency was expected during coronary artery bypass grafting, we performed percutaneous coronary intervention to the culprit lesion first, and then intravenous immunoglobulin and high dose dexamethasone were tried. His platelet count rose from 49,000 to 103,000/mm3, so we performed coronary artery bypass grafting. The patient had no postoperative hemorrhagic complications. We believe that high dose dexamethasone therapy is useful for patients with ITP who need surgery immediately.
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OBJECTIVE To discuss the factors affecting the blood concentration of high-dose methotrexate （HD-MTX） and the occurrence of adverse drug reactions （ADR） when treating lymphoma with HD-MTX. METHODS From July 2020 to November 2021， the information of HD-MTX patients who had been monitored for HD-MTX blood drug concentration in the First Affiliated Hospital of Guangdong Pharmaceutical University was collected by retrospective analysis， such as medical record number， age， sex， height， body mass， chemotherapy plan， dosage； test indexes such as alanine transaminase， aspartate transaminase， total bilirubin， creatinine clearance （CrCl）， albumin （ALB） and other indexes were also collected before and after administration. The blood concentrations （c6 h， c24 h， c48 h） of HD-MTX were recorded， drug information of proton pump inhibitors （PPIs） was extracted and used， and ADR occurring within 48 h after administration were all evaluated. Single factor analysis， multiple linear regression and χ2 test were used to analyze the influential factors. RESULTS A total of 133 patients were included in this paper. The results of the single factor analysis of HD-MTX blood drug concentration showed that age， CrCl had an effect on c 6 h （P＜0.05）； age， CrCl and ALB had an effect on c24 h （P＜0.05）； age， body mass index （BMI）， CrCl， combined use of PPIs and ALB had an effect on c48 h （P＜0.05）. The results of multiple linear regression analysis showed that age and CrCl had no effect on c 6 h （P＞0.05）， age was the main influential factor of c 24 h （P＜0.05）， and CrCl and combined use of PPIs were the main influential factors of c48 h （P＜0.05）； the coefficient of variance expansion was between 1 and 3.5， indicating that the analysis results were acceptable. The overall incidence of adverse reactions was 51.13%， of which the blood and lymphatic system reactions were the most common. The results of the influential factors of ADR showed that age， BMI， liver function and CrCl had effect on the incidence of ADR （P＜0.05）. CONCLUSIONS During the process of HD-MTX in the treatment of lymphoma， the patient’s age， CrCl and combined use of PPIs should be considered， and the patient’s blood concentration should be monitored； at the same time， the age of patients， BMI， liver function and CrCl have an impact on the incidence of ADR.
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Objective:To conduct a meta-analysis to analyze the efficacy and adverse reactions of fractionated high dose rate brachytherapy (HDR-BT) as monotherapy for localized prostate cancer.Methods:Relevant databases were searched to collect the clinical trials on HDR-BT as monotherapy in patients with localized prostate cancer. Included studies were limited to full-text publications of fractionated HDR-BT as monotherapy with a median follow-up of at least 5 years, and adequate reporting of treatment outcomes and adverse reactions data. Stata 12.0 was used for data analysis.Results:According to the inclusion and exclusion criteria, a total of 11 clinical trials involving 2 683 patients with prostate cancer were included in this meta-analysis. The results of the meta-analysis showed that 5-year biochemical recurrence-free survival (bRFS) rate and overall survival (OS) rate were 94% (95% CI: 93% - 96%) and 96% (95% CI: 94% - 98%), respectively. Long-term (≥5 years) cancer-specific survival (CSS) rate and distant metastasis-free survival (DMFS) rate were 99% (95% CI: 98% - 100%) and 98% (95% CI: 98% - 99%), respectively. Long-term (≥5 years) late grade ≥3 grade gastrointestinal and genitourinary adverse reactions rates were 2% (95% CI: 1% - 3%) and 9% (95% CI: 6% - 13%), respectively. Conclusions:Fractionated HDR-BT as monotherapy is an effective treatment for patients with localized prostate cancer. Its long-term efficacy is encouraging, and the treatment is well tolerated and safe.
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In recent years, ultra-high dose rate (FLASH) radiotherapy has become one of the most advanced research topics in the field of radiotherapy. Experimental data indicate that FLASH radiotherapy can significantly reduce the irradiation damage in normal tissues while being as effective as clinical conventional dose rate radiotherapy in tumor control. The oxygen depletion hypothesis is considered as one of the key mechanisms underlying the FLASH effect. In this article, research progress on the discovery, experimental evidence and reaction principle of oxygen depletion was reviewed, the measurement methods and biological effect modeling methods of the oxygen depletion hypothesis were summarized, and the oxygen depletion difference between normal tissue and tumor was also discussed.
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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.
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Objective:To study the effects of FLASH irradiation (FLASH-RT) and conventional irradiation (CONV-RT) on gene expression profile in mouse liver, in order to provide theoretical basis of the potential mechanism of FLASH-RT.Methods:A total of 11 C57BL/6J male mice were divided into healthy control group (Ctrl group), CONV-RT group and FLASH-RT group according to random number table method. Mouse abdomen was treated with 12 Gy CONV-RT or FLASH-RT. Then the mice were killed by neck removal, and the liver tissues were collected to extract total RNA for transcriptome sequencing (RNA-Seq) that was then analyzed by bio-informatics analysis to investigate the changes of gene expression profiles. The mRNA expression levels of Stat1, Irf9 and Rela were verified by quantitative real-time PCR assay.Results:1 762 differentially expressed genes (DEGs) were identified in group FLASH-RT vs. CONV-RT. Among them, 660 genes were up-regulated and 1 102 genes were down-regulated. 1 918 DEGs were identified in groups FLASH-RT vs. Ctrl. Among them, 728 genes were up-regulated and 1 190 genes were down-regulated. 1 569 DEGs were identified in group CONV-RT vs. Ctrl. Among them, 1 046 genes were up-regulated and 523 genes were down-regulated. According to Gene Ontology (GO) analysis, these DEGs from groups FLASH-RT vs. CONV-RT were involved in various functions including defense response to virus, other organisms in cell components, adenylyltransferase activity in molecular function activity. These DEGs from group FLASH-RT vs. Ctrl were involved in various functions including defense response to other oranisms, endoplasmic reticulum chaperone complex, double-stranded RNA binding and so on. These DEGs from group FLASH-RT vs. CONV-RT were involved in several Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including influenza A, Herpes simplex infection and so on. These DEGs from group FLASH-RT vs. Ctrl were involved in several KEGG pathways including influenza A, NOD-like receptor signaling pathway. Stat1 was likely to be activated by FLASH radiation. The quantitative real-time PCR assay showed that FLASH-RT obviously increased the mRNA expressions of Stat1, Irf9 and Rela ( t=6.62, 2.11, 1.67, P<0.05). Conclusions:FLASH-RT and CONV-RT could alter gene expression profiles in mouse liver tissues, and these DEGs are involved in multiple radiobiological functional pathways. In comparison with CONV-RT, FLASH-RT induces a low level of liver injury, which may due to hypoxia radiation resistance.
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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.
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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.
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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.
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@#AIM:To study the effect of vitamin E on the injury of human retinal pigment epithelial(hRPE)cells induced by high-dose blue light, and provide experimental evidence for intercepting blue light damaged hRPE cells. <p>METHODS: The hRPE cell injury model was established with 3000±150Lx blue light. The apoptosis rate and reactive oxygen species(ROS)of the six groups of hRPE cells were detected by flow cytometry at 0, 3, 6, 9, 12 and 24h respectively. Apoptosis and ROS in hRPE cells were detected by cytometry in 0h-irradiation group, 6h-irradiation group, and vitamin E added groups(vitamin E concentration 10, 50, 100μmol/L)before or after 6h-irradiation. The fluorescence intensity of hRPE cells was observed under a fluorescence microscope using Hoechst 33258 staining reagent.<p>RESULTS: Compared with the 0h-irradiation group, the relative amount of reactive oxygen species increased significantly in 3, 6, 9, 12 and 24h groups(all <i>P</i><0.01), the apoptosis rate of hRPE cells increased significantly in 6, 9, 12 and 24h groups(all <i>P</i><0.01), the apoptosis rate of the 3h-irradiation group was not statistically significantly increased(<i>P</i>=0.46). Compared with the 6h-irradiation group, the relative amounts of ROS and apoptotic rate of the six groups of hRPE cells added vitamin E were significantly decreased, and the blue fluorescence of Hoechst 33258 released in the cells gradually decreased, which was concentration dependent(all <i>P</i><0.01),except for apoptosis rate of hRPE cells in the 10 μmol/L vitamin E group before irradiation(<i>P</i>=0.66). Compared with the 0h-irradiation group, the difference in the relative amount of ROS and apoptosis rate of hRPE cells in added groups were statistically significant(all <i>P</i><0.01). At the same concentration of vitamin E, the relative amount of ROS and apoptosis rate of hRPE cells added vitamin E after irradiation were significantly lower than those added vitamin E before irradiation(all <i>P</i><0.01), except for apoptosis rate of hRPE cells in the 10 μmol/L vitamin E group, which had no difference between added before and after irradiation(<i>P</i>=0.08).<p>CONCLUSION: After hRPE cells had been irradiated by blue light, the increase in the relative amount of intracellular ROS was earlier than that of apoptosis. Elimination of intracellular ROS is the idea of intercepting high doses of blue light induced hRPE cell injury. Vitamin E protects RPE cell against damage induced by high doses of blue light, and the effect becomes stronger as the concentration of vitamin E increases, which is better when added after irradiating. However, it doesn't take effect until the concentration reaches a certain level. And the damage can't be completely repaired.
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Brachytherapy has played an important role in localized prostate cancer. High-dose-rate brachytherapy has evolved over the decades, as either monotherapy or in combination with external beam, it offers many advantages over other treatment alternatives. Precise control over dose delivery allows for focal dose escalation while sculpting dose around organs at risk to maintain excellent tolerance. The high dose per fraction exploits the low α/β ratio of prostate cancer and triggers transcriptional changes in the tumor genome, thereby enhancing radiation sensitivity. In this article, the development, patient selection, application of techniques, clinical efficacy and adverse events for high-dose-rate brachytherapy were summarized.
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Evidence-based Practice Guideline of Medication Therapy of High-dose Methotrexate in China was published in the British Journal of Clinical Pharmacology in February 2022. The guideline followed the latest definition of clinical practice guideline and the methodology specification for the guideline development of WHO. The Grading of Recommendations Assessment ， Development，and Evaluation （GRADE）approach was applied to rate the quality of evidence and determine the strength of recommendations. Finally ，this guideline presents 28 recommendations covering the whole process of clinical medication of high-dose methotrexate ，involving evaluation prior to administration （liver and renal function ，pleural effusion and ascites ， comedication，genetic testing ），pre-treatment and routine dosing regimen （pretreatment of hydration and alkalization ，urine alkalization，routine dosing regimen ），therapeutic drug monitoring （necessity，method，timing，target concentration ），leucovorin rescue（rescue timing ，rescue regimen ，rescue dose optimization ），and management of toxicities （liver and kidney function monitoring，supportive treatment ，blood purification treatment ）. This article aims to summarize and interpret the recommendations of this guideline ，so as to promote the better promotion and implementation of this guideline and provide comprehensive technical support and suggestions for whole-course individualized administration of high-dose methotrexate in China.
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Objective:To outline clinical features in syndrome of resistance to thyroid hormone(RTH) and thyrotropin-secreting pituitary adenoma(TSH adenoma) based on a case series, and to assess the value of octreotide suppression test and high-dose dexamethasone suppression test(HDDST) in differentiating the two diseases.Methods:A total of 22 cases with RTH and TSH adenoma clinically diagnosed in Xiangya Hospital of Central South University from October 2010 to December 2021 were retrieved. The clinical characteristics of the two diseases and results to different tests were analyzed and summarized.Results:(1) The tumors in TSH adenoma patients were larger than those with RTH complicated with pituitary mass, which presented chiasmatic compression on images( P<0.05). (2) In octreotide suppression test, thyrotropin(TSH) inhibition rate in RTH patients was lower than that in TSH adenoma patients( P<0.05). In HDDST, TSH inhibition rate was higher in patients with RTH than in patients with TSH adenoma( P<0.05). (3) The TSH inhibition rate was calculated by receiver operating characteristic(ROC) curve. The sensitivity and specificity of octreotide suppression test were 91.9% and 55.6%, respectively, and the threshold value of TSH inhibition rate was 64.24%. The sensitivity and specificity of HDDST were 54.4% and 89.0%, respectively, and the threshold value of TSH inhibition rate was 65.73%.The combined sensitivity and specificity of the two tests were 77.8% and 90.9%, indicating better diagnostic value( P<0.05). Conclusions:The combination of octreotide suppression test and HDDST is of clinical value in differentiating RTH from TSH adenoma. TSH adenoma is more aggressive than that of pituitary adenoma with RTH.
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Objective:To evaluate the 3-year survival outcomes and late injury between the self-designed patent single-channel applicator, which was modified from the traditional tandem applicator and wrapped with a oval-shield alloy around the source channel and standard Fletcher-type applicator in the high-dose-rate brachytherapy for cervical cancer.Methods:Patients initially diagnosed with cervical cancer in the Affiliated Hospital of Southwest Medical University from December 2011 to April 2017 were enrolled and randomly assigned into the external beam radiotherapy (EBRT)+ single-channel intracavitary applicator group (the patent single-channel group) and EBRT+ the Fletcher applicator group. The whole pelvis irradiation was delivered with 6-MV photons via a four-field box variant or anterior and posterior parallel fields. Five to six fractions of intracavitary brachytherapy were performed at a dose of 7 Gy at point A once a week after 30 Gy (Equivalent Dose in 2 Gy at point A: 80-90 Gy). Chemotherapy was given with intravenous injection of cisplatin at a dose of 40 mg/m 2 once weekly during EBRT. Clinical efficacy and safety were evaluated after corresponding treatment. Results:In total, 150 eligible cases were assigned into the Fletcher applicator group and 149 cases into the patent single-channel group. Up to December 2020, all patients had been followed up for 3 years, and the median duration of follow-up was 61 months. In the Fletcher group, the 3-year overall survival, progression-free survival and locoregional failure-free survival was 76.3%, 78.1% and 75.4%, and 83.8%, 80.3% and 85.5% in the single-channel group, respectively. In the Fletcher group, the cumulative rate of grade 3-4 late rectal complications was 3.3% and 6.7% in the single-channel group ( P=0.122). The cumulative rate of grade 3-4 bladder complications was 1.3% in the Fletcher group and 0.7% in the single-channel group ( P=1.000). Conclusion:The self-designed patent single-channel intracavitary applicator yields equivalent long-term clinical efficacy and safety to the standard Fletcher-type three-channel applicator in the HDR brachytherapy for uterine cervical cancer.
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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.
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Objective:To investigate the application of therapeutic grade ionization chamber to rapid measurement of short pulsed and high-dose-rate X-ray.Methods:The half-value layer of pulsed X-ray caused by an electron accelerator was measured by interpolation method and its equivalent energy was estimated. The cumulative doses from a certain amount of pulsed radiation at different distances in the same direction around the equipment were compared using the therapeutic grade ionization chamber and thermoluminescence measurement method . The relationship between the measurement result by using ionization chamber dosimeter and the distances away from source was analyzed. The cumulative doses from a certain amount of pulsed radiation at the same location at different frequencies were compared.Results:In working condition, 100 pulses of radiation were received accumulatively at 1 to 12 meters away from the outer wall of the equipment. The range of air Kerma was 0.08-9.65 mGy measured by using thermoluminescence dometers and 0.08 - 9.85 mGy using the ionization chamber dosimeters, respectively. The difference between both is within 10%. At different frequencies (1-10 Hz), there was no significant difference in X-ray air Kerma from 100 pulses measured by ionization chamber dosimeter at 2 m away from the front of the equipment ( P>0.05). Conclusions:The therapeutic grade ionization chamber dosimeter can be used for the rapid measurement of short pulsed X-ray radiation dose in the range of dose rates and pulse frequencies involved in the experimental accelerator device.
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Septic shock refers to sepsis combined with severe circulatory disorders and cell metabolism disorders, with high incidence, high fatality rate, and dangerous condition.It is one of the leading cause of death in children in pediatric intensive care units.Therefore, early diagnosis and effective treatment of septic shock are very important.Among them, fluid resuscitation is an important part of treatment.However, the research in recent years has a lot of controversy about subsequent fluid balance management issues.This review summarized fluid balance therapy, focusing on the large dose of fluid resuscitation on the prognosis of children with septic shock, aiming to provide a reference for the future improvement of fluid therapy for children with sepsis.
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Brachytherapy plays an important role in radical radiotherapy of cervical cancer. At present, most hospitals in China use high-dose-ate brachytherapy, which irradiatevolume by simulating line source with a single approximate point source. Therefore, the dwell positions and dwell times can be optimized appropriately. However, due to various reasons, the initial state of the optimization plan must start from the standard loading pattern, and ensure that the optimized plan basically maintains the pear-shaped dose distribution. This paper introduces the standard loading pattern of intracavitary brachytherapy and intracavitary combined interstitial brachytherapy for cervical cancer through literature review, and expounds the planning optimization model and the constraints in the optimization process, to provide important reference for the planning of brachytherapy for cervical cancer.
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Abstract Objective To compare the effect of high-dose vitamin A (HD Vit-A) use during postmolar follow-up of patients with low and plateauing (L&P) serum human chorionic gonadotropin (hCG) levels, from the moment serum hCG plateaued (P-hCG) to the first normal serum hCG value (< 5IU/L). Methods The present retrospective series case study compared two nonconcurrent cohorts of patients. Control group (CG): 34 patients with L&P serum hCG levels who underwent expectant management for 6 months after uterine evacuation, from 1992 to 2010; study group (SG): 32 patients in similar conditions who received 200,000 IU of Vit-A daily, from the identification of a P-hCG level to the first normal hCG value or the diagnosis of progression to gestational trophoblastic neoplasia (GTN), from 2011 to 2017. The present study was approved by the Ethics Committee of the institution where it was conducted. Results In both groups, the prevalence of persistent L&P serum hCG levels was < 5%. In the SG, hCG levels at plateau were higher (CG = 85.5 versus SG = 195 IU/L; p = 0.028), the rate of postmolar GTN was lower (CG = 29.4% versus SG = 6.3%, p = 0.034) and follow-up was shorter (CG = 14 versus SG = 10 months, p < 0.001). During GTN follow-up, there were no differences in GTN staging or treatment aggressiveness in both groups. High-dose Vit-A use did not have any relevant toxic effect. There were no GTN relapses or deaths. Conclusion The limited use of HD Vit-A seems to have a safe and significant effect on the treatment of postmolar patients with L&P serum hCG levels and may decrease the development of postmolar GTN in this population.
Resumo Objetivo Comparar o efeito de alta dose de vitamina A (VitA) no seguimento pósmolar de pacientes com gonadotrofina coriônica humana (hCG) sérica apresentando valoresbaixoseem platô(L&P). Métodos Estudo retrospectivo de série de casos comparando duas coortes não simultâneas. Grupo controle (CG): 34 pacientes com títulos de hCG sérico L&P submetidos a manejo expectante por 6 meses após o esvaziamento uterino, de 1992 a 2010; Grupo de Estudo (SG): de 2011 a 2017, 32 pacientes em condições semelhantes de hCG receberam Vit-A na dose de 200.000 IU por dia, do momento da identificação dohCG em platôate o primeirohCG normaloudiagnóstico de progressão para neoplasia trofoblástica gestacional (NTG). O presente estudo foi aprovado pelo Comitê de Ética da Instituição na qual foi desenvolvido. Resultados Em ambososgrupos, aprevalência de hCGL&P foi < 5%. No SG, os níveis de hCGemplatô forammaiores (CG = 85.5 versus SG = 195 IU/L; p = 0,028), e foram significantemente menores tanto a prevalência de NTG pós-molar (CG = 29.4% versus SG = 6.3%, p = 0,034) como o tempo de seguimento (CG = 14 versus SG = 10 meses, p < 0.001). Na evolução para NTG não houve diferença no estadiamento da Interna tional Federation of Gynecology and Obstetrics (FIGO, na sigla em inglês) ou na agressividade do tratamento. Com altas doses de Vit-A não houve qualquer efeito tóxico relevante. Não houve casos de recidiva de NTG ou de óbito. Conclusão O uso limitado de altas doses de Vit-A parace ser seguro e apresenta efeitos significativos na evolução de pacientes em controle pós-molar com títulos de hCG sérico L&P, e pode diminuir o desenvolvimento de NTG pós-molar nessa população.