Immune cell membrane-based biomimetic nanomedicine for treating cancer metastasis

Metastasis is the leading cause of cancer-related death. Despite extensive treatment, the prognosis for patients with metastatic cancer remains poor. In addition to conventional surgical resection, radiotherapy, immunotherapy, chemotherapy, and targeted therapy, various nanobiomaterials have attracted attention for their enhanced antitumor performance and low off-target effects. However, nanomedicines exhibit certain limitations in clinical applications, such as rapid clearance from the body, low biological stability, and poor targeting ability. Biomimetic methods utilize the natural biomembrane to mimic or hybridize nanoparticles and circumvent some of these limitations. Considering the involvement of immune cells in the tumor microenvironment of the metastatic cascade, biomimetic methods using immune cell membranes have been proposed with unique tumor-homing ability and high biocompatibility. In this review, we explore the impact of immune cells on various processes of tumor metastasis. Furthermore, we summarize the synthesis and applications of immune cell membrane-based nanocarriers increasing therapeutic efficacy against cancer metastases via immune evasion, prolonged circulation, enhanced tumor accumulation, and immunosuppression of the tumor microenvironment. Moreover, we describe the prospects and existing challenges in clinical translation.

Research on anti-tumor mechanism of attenuated Salmonella typhimurium VNP20009 / 药学学报

Attenuated Salmonella typhimurium VNP20009 is a widely used natural oncolytic bacterium, which has great application potential given its unique characteristics, including clinical safety, tumor targeting specificity, and explicit genome sequence. Here, we show that tumor progression can be effectively reduced by intraperitoneal administration with VNP20009 in a mouse model of melanoma (all animal experiments were conducted in accordance with the Animal Ethics Committee of China Pharmaceutical University); co-culture experiment in vitro demonstrated that VNP20009 can induce the polarization of macrophage M1, accompanied by expression of inflammation-related factors; flow cytometry analysis showed that VNP20009 induced the increase of immune cell infiltration in tumor. Further analysis showed that T cells infiltration in tumor-draining lymph node (TDLN) increased, and VNP20009 induced the activation of CD4+ T cells and CD8+ T cells in tumor. Our results demonstrate that VNP20009 treatment significantly inhibited melanoma tumors by remodeling tumor-associated macrophages to an M1-like phenotype, as well as recruiting and activating cytotoxic T cells, combined with its own antigenic activity to exert anti-tumor immunity.

Enabler of Evidence-based Physical Therapy: Physiotherapy Evidence Database (PEDro) / 中国康复理论与实践

Physiotherapy Evidence Database (PEDro) is a free, web-based database containing randomized controlled trial reports, systematic reviews and evidence-based clinical practice guidelines for physical therapy, which has been searched millions of times a year by users around the world, and may improve the development of evidence-based physiotherapy in China.

Application of CRISPR/Cas9 lentiviral vector in construction of rat hepatic stellate cells with COX-2 gene knockout / 临床肝胆病杂志

ObjectiveTo obtain HSC-T6 cells with stable expression of Cas9 protein and HSC-T6-COX-2-/- cells with COX-2 gene defect by transfecting HSC-T6 cells with CRISPR/Cas9 lentiviral vector, and to provide a good method for further functional research and new strategies for the clinical treatment of liver fibrosis. MethodsThe COX-2 gene-specific sgRNAs (COX-2-sgRNA-1, COX-2-sgRNA-2, COX-2-sgRNA-3) were designed, synthesized, and connected to the GV371 vector, and the recombinant plasmid and the packaging plasmid were transfected into 293T cells to form lentivirus particles; the fluorescence method was used to measure virus titer. The most appropriate amount of the virus was calculated based on MOI. Lenti-Cas9-puro was transfected into HSC-T6 cells, and HSC-T6-Cas9 cells were screened out by puromycin; Lenti-COX-2-sgRNA-EGFP was transfected into HSC-T6-Cas9 cells to obtain HSC-T6-COX-2-/- cells. Cruiser enzyme digestion and Western blot were used to verify gene knockout at the gene and protein levels. An analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsSequencing verified that the COX-2-sgRNA expression vector was constructed successfully. Recombinant expression plasmids and packaging plasmids were transfected into 293T cells to form lentivirus particles, and the fluorescence method showed a virus titer of ＞1×108. HSC-T6 cells with stable expression of Cas9 protein and HSC-T6-COX-2-/- cells with COX-2 gene defect were successfully constructed. The HSC-T6-Cas9 group had significantly higher relative mRNA expression of LV-Cas9-Puro than the CON group (541.93±105.76 vs 1.00±0.02, t=12.995, P＜0.01). Cruiser enzyme digestion and Western blot showed that the CRISPR/Cas9 lentivirus expression vectors played a role in the target, among which COX-2-sgRNA-2 knockout had the most significant effect, and this group had a significant reduction in the protein expression level of COX-2 compared with the CON group and the NC group (both P＜0.05), suggesting that COX-2-sgRNA was active. ConclusionA CRISPR/Cas9 lentivirus vector is successfully constructed for COX-2 target gene, and HSC-T6-COX-2-/- cells with stable COX-2 gene knockout are obtained.

Effect of cyclooxygenase-2 inhibitors on the expression of the Acsl gene family in the ileum of rats with nonalcoholic fatty liver disease / 临床肝胆病杂志

ObjectiveTo investigate the effect and significance of cyclooxygenase-2 (COX-2) inhibitors on the expression of the Acsl gene family in the ileum of rats with nonalcoholic fatty liver disease (NAFLD). MethodsA total of 45 Sprague-Dawley rats were randomly divided into normal control group (15 rats given normal diet), NAFLD model group (15 rats given high-fat diet), and nimesulide group (15 rats given high-fat diet and nimesulide). All rats were sacrificed after 12 weeks of feeding, and then blood samples were collected from the inferior vena cava to measure total cholesterol (TC) and triglyceride (TG). HE staining and oil red O staining were performed for the liver to evaluate the degree of hepatic steatosis in each group, and quantitative real-time PCR was used to measure the mRNA expression of the Acsl family genes in the ileum. An analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsCompared with the normal control group, the NAFLD model group had significant increases in serum TC and TG and marked hepatic steatosis (all P＜0.05); compared with the NAFLD model group, the nimesulide group had significant reductions in serum TC and TG and degree of hepatic steatosis (all P＜0.05). Compared with the normal control group, the NAFLD model group had a significant increase in the expression of COX-2 in the ileum (P＜0.05), and compared with the NAFLD model group, the nimesulide group had a significant reduction in the expression of COX-2 in the ileum (P＜005). Compared with the normal control group, the NAFLD model group had significant increases in the mRNA expression of Acsl3 and Acsl5 in the ileum (both P＜0.05), and compared with the NAFLD model group, the nimesulide group had significant reductions in the mRNA expression of Acsl3 and Acsl5 (both P＜0.05). ConclusionThe COX-2 inhibitor nimesulide can regulate the expression of the Acsl gene family in the ileum of rats with NAFLD, suggesting that COX-2 inhibitors may inhibit the progression of NAFLD through the Acsl gene.

Research progress on diagnosis of glaucoma associated with corneal refractive surgery / 国际眼科杂志(Guoji Yanke Zazhi)

@#Given the popularity of corneal refractive surgery and an aging population of patients who have undergone this procedure, those patients will likely require the diagnosis, follow-up, and management of glaucoma in the future. Since glaucoma examination metrics such as intraocular pressure depend largely on corneal properties, patients who plan to undergo corneal refractive surgery must also undergo a thorough glaucoma examination in order for the ophthalmologist to monitor the development and progress of glaucoma. This article presents an overview of related research on the diagnosis of glaucoma before and after corneal refractive surgery in order to provide reference for clinical work.

A multicenter survey of antibiotic use in very and extremely low birth weight infants in Hunan Province / 中国当代儿科杂志

OBJECTIVE@#To investigate the current status of antibiotic use for very and extremely low birth weight (VLBW/ELBW) infants in neonatal intensive care units (NICUs) of Hunan Province.@*METHODS@#The use of antibiotics was investigated in multiple level 3 NICUs of Hunan Province for VLBW and ELBW infants born between January, 2017 and December, 2017.@*RESULTS@#The clinical data of 1 442 VLBW/ELBW infants were collected from 24 NICUs in 2017. The median antibiotic use duration was 17 days (range: 0-86 days), accounting for 53.0% of the total length of hospital stay. The highest duration of antibiotic use was up to 91.4% of the total length of hospital stay, with the lowest at 14.6%. In 16 out of 24 NICUs, the antibiotic use duration was accounted for more than 50.0% of the hospitalization days. There were 113 cases with positive bacterial culture grown in blood or cerebrospinal fluid, making the positive rate of overall bacterial culture as 7.84%. The positive rate of bacterial culture in different NICUs was significantly different from 0% to 14.9%. The common isolated bacterial pathogens Klebsiella pneumoniae was 29 cases (25.7%); Escherichia coli 12 cases (10.6%); Staphylococcus aureus 3 cases (2.7%). The most commonly used antibiotics were third-generation of cephalosporins, accounting for 41.00% of the total antibiotics, followed by penicillins, accounting for 32.10%, and followed by carbapenems, accounting for 13.15%. The proportion of antibiotic use time was negatively correlated with birth weight Z-score and the change in weight Z-score between birth and hospital discharge (r=-0.095, -0.151 respectively, P<0.01), positively correlated with death/withdrawal of care (r=0.196, P<0.01).@*CONCLUSIONS@#Antibiotics used for VLBW/ELBW infants in NICUs of Hunan Province are obviously prolonged in many NICUs. The proportion of routine use of third-generation of cephalosporins and carbapenems antibiotics is high among the NICUs.

Urodynamic assessment of bladder storage function after radical hysterectomy for cervical cancer / 中华医学杂志(英文版)

BACKGROUND@#After radical hysterectomy for cervical cancer, the most common complication is lower urinary tract symptoms. Post-operatively, bladder capacity can alter bladder function for a prolonged period. This study aimed to identify factors affecting bladder storage function.@*METHODS@#A multicenter, retrospective cohort study was conducted. Information of patients with stages IA2 to IIB cervical cancer with urodynamic study results were retrospectively collected from nine hospitals between June 2013 and June 2018 according to the inclusion criteria. Demographic, surgical, and oncological data were collected. The univariate and multivariate logistic regression was used to identify clinical factors associated with bladder storage function.@*RESULTS@#Two hundred and three patients with cervical cancer had urodynamic testing post-operatively. Ninety-five (46.8%) patients were diagnosed with stress urinary incontinence (SUI). The incidence of low bladder compliance (LBC) was 23.2%. Twenty-seven (13.3%) patients showed detrusor overactivity (DO). Fifty-seven patients (28.1%) presented with a decreased maximum cystometric capacity (DMCC). The probability of composite bladder storage dysfunction was 68.0%. Multivariate analysis confirmed that laparoscopy represents a protective factor for SUI with an odds ratio of 0.498 (P = 0.034). Patients who underwent a nerve-sparing procedure were less odds to experience SUI (P = 0.014). A significant positive correlation between LBC and DO was observed (P < 0.001). A greater length of the resected vagina and chemoradiotherapy were common risk factors for LBC and DO, while radiotherapy exerted a stronger effect than chemotherapy. Additionally, patients who received chemoradiotherapy frequently developed a DMCC. The follow-up time was not correlated with bladder storage function.@*CONCLUSION@#A nerve-sparing procedure without longer resected vagina is recommended for protecting the bladder storage function.

Research progress of graphene and its derivatives in regenerative medicine / 中华整形外科杂志

Graphene is a monatomic layer honeycomb-like crystal formed by bonding of carbon atoms with SP2. As a novel material, graphene and its derivatives are possessed of advantages on mechanical, electrical, optical and thermal properties and have become a hot research interest in multiple fields. Graphene and functionalized derivatives have great potential in medical applications, due to their advantages of not only easy preparation and less spend, but also excellent properties of antibacterial ability and biocompatibility. This review summarized the updated research progress of graphene and its derivatives, and their complexes, in regenerative medicine, including the antibacterial mechanism, biocompatibility and application.

Epidemiological characteristics of malaria from 1951 to 2018 in Sanya city of Hainan Province, China

Objective: To analyze the progress of eliminating malaria and the epidemiological characteristics of malaria in Sanya city, Hainan Province, China, from 1951 to 2018. Methods: This study used the historical data analysis method which belongs to descriptive study to analyze the epidemiological characteristics of malaria. The data were obtained from previous historical records of the Center for Disease Control and Prevention in Sanya. Microsoft Excel 2010 and IBM SPSS 21.0 software were used for data collation and analysis. Results: The malaria prevention and control in Sanya experienced three main stages. Time during 1951-1983 is the period of controlling malaria epidemic, 1984-2009 is the period of regular management, and 2010-2018 is the period of eliminating malaria. From 1951 to 2018, the incidence of malaria showed a long-term trend of gradual decline. The average annual incidence rates were 268.55 per 10 000 people during 1951-1983, 22.96 per 10 000 people during 1984-2009, and 0.026 per 10 000 people during 2010-2018, respectively. The highest incidence of malaria in history was in 1956 and the incidence was 1 030.60 per 10 000 people. From 1951 to 2018, the incidence of malaria was high in all months througout the year, with the highest incidence in July. The distribution characteristics of the insect species were as follows: before 1981, the reported cases were mainly Plasmodium falciparum malaria; from 1981 to 2014, the reported cases were Plasmodium falciparum malaria and Plasmodium vivax malaria; and the local cases were quartan malaria in 2015. As for the characteristics of the vectors: before 1960, Anopheles minimus was the main vector of malaria transmission, and after 1980, Anopheles dirus was the main vector. Conclusions: From 1951 to 2018, the incidence of malaria in Sanya decreased gradually and showed a trend of elimination.

Construction of theoretical model of traditional Chinese medicine intelligent manufacturing / 中国中药杂志

In the process of transforming and upgrading of traditional Chinese medicine( TCM) intelligent manufacturing,the TCM enterprises lack systematic and in-depth research on intelligent manufacturing of TCM,leading to insufficient understanding of relevant concepts,development direction,development content and other aspects,to some extent,causing fuzzy and chaotic phenomena. The theoretical model,as a higher expression level of scientific thinking,has the function of interpretation and prediction,and can provide theoretical basis as well as guide for scientific research. Therefore,this article aims to construct a theoretical model of TCM intelligent manufacturing based on the concept of flexible production and intelligent equipment for some unhealthy phenomena in the development process of TCM intelligent manufacturing. In the TCM intelligent manufacturing system,with theory model as the core,the new-generation information technology was integrated with the TCM manufacturing technology to realize the integration of informationization and industrilization as well as the landing of theoretical model. Then,a 3 D simulation model was established to provide a visual environment for intelligent manufacturing of TCM and simulate the virtual reality throughout the TCM intelligent manufacturing process. The new theoretical model in this paper,to a certain extent,can play a guiding role in the development of TCM intelligent manufacturing,and can also provide reference for the realization of TCM intelligent manufacturing.

Correlative study of bufogenin constituents in venom of Bufo bufo gargarizans / 中国中药杂志

As known,simultaneous determination of various chemical indicators is one of the future trends in quality control of traditional Chinese medicines because of the extremely complex chemical compositions. This project is to screen the quality markers that can accurately control the quality of the Bufonis Venenum by exploring the intrinsic correlation of components. In this study,venom of Bufo bufo gargarizans from 17 different sources were used as research samples,and the contents of 7 bufogenin were determined by HPLC-DAD. Then,the data obtained were analyzed by Spearman correlation analysis and principal component analysis( PCA). In addition,a stepwise regression analysis was used to establish a predictive model for the contents of the seven bufogenin components( independent variable) and the total contents of the bufogenin( dependent variable). The results indicated that there is a significant positive correlation between the contents of telocinobufagin and cinobufotalin,and there is a significant positive correlation between the contents of bufalin,cinobufagin and resibufogenin. In contrast,the contents of telocinobufagin and cinobufotalin are negatively correlated with the contents of bufalin,cinobufagin and resibufogenin. However,the correlation between gamabufotalin and bufotalin and other components are not obvious. Furthermore,further study found that there is a correlation between the sum of the contents of bufalin,cinobufagin and telocinobufagin and the total contents of the bufogenin. In fact,the application of bufalin,cinobufagin and telocinobufagin as the quality control indicators of the Bufonis Venenum can better reflect the quality characteristics of the Bufonis Venenum compared with the previous quality control indicators. The conclusions will provide a reference for the revision of the quality standards of the Bufonis Venenum.

Application of double-low technique and iterative reconstruction in 64-slice MSCT pulmonary angiography / 医疗卫生装备

The development of CT and the clinical application of CT pulmonary angiography (CTPA) in diagnosing pulmonary embolism were introduced,and the methods for decreasing CTPA radiation dose and the importance of iterative reconstruction for low-dose scanning were analyzed.The development and application of contrast agent were described,and the ways to reduce contrast agent dose was expounded.Double-low CTPA combined with iterative reconstruction was pointed out to decrease greatly the radiation dose and contrast agent iodine dose while ensured image quality,and thus the damages to the patient by radiation and contrast agent could be lowered at the most.

Study on the correlation between frailty of elderly patients and short-term prognosis after abdominal surgery / 中国实用护理杂志

Objective To study the correlation between preoperative frailty and short-term prognosis after abdominal surgery, and to explore its predictive value. Methods A total of 156 elderly patients undergoing abdominal surgery from July 2017 to December 2017 in Tianjin Third Center Hospital were prospectively observed and classified into non-frail group, pre-frail group and frail group according to the Fried's frailty phenotype before surgery. The postoperative hospital stay and incidence of adverse outcomes were compared among the three groups, and the effect of frailty on the risk prediction model of the American Society of Anesthesiology (ASA) was analyzed. Results The postoperative hospital stay and the incidence of adverse outcomes in the three groups were statistically significant (P<0.05). Negative binomial regression analysis found that preoperative frailty was associated with prolonged postoperative hospital stay (pre-frail incidence rate ratio was 1.428 (95% CI : 1.250-1.974);frail incidence rate ratio was 3.692 (95% CI : 1.282-4.230) .Logistic regression analysis found that preoperative frailty was associated with an increased risk of postoperative adverse outcomes (pre-frail: OR=2.303(95% CI : 1.810-4.127); frail: OR=3.512 (95% CI : 2.054-5.689)). Frailty increased the diagnostic value of the ASA risk prediction model (Z=3.718, P<0.01). Conclusions Frailty of elderly patients is an important predictor of short-term prognosis of abdominal surgery, and it increases the diagnostic value of ASA risk model. The preoperative frailty assessment of elderly patients undergoing abdominal surgery is helpful for preoperative clinical decision-making and prognosis evaluation.

Effect of the discrepancy of the dose calculation results of different algorithms on CyberKnife lung tumor treatment plan / 中华放射肿瘤学杂志

Objective To evaluate the effect of the discrepancy of the dose calculation results of different algorithms upon the CyberKnife lung tumor treatment plan,and assess the impact of tumor volume and location on the dose calculation results. Methods Thirty-two cases of lung tumors were treated with MultiPlan 5.2.1 planning system of CyberKnife VSI.Ray Tracing and Monte Carlo algorithms were adopted to calculate the dose distribution, and then the calculation results were statistically compared between two algorithms. Results For the enrolled cases,the calculation results of these two algorithms demonstrated that the deviation range of prescription dose coverage of planning target volume (PTV),conformal index,new conformal index and uniformity index were 0.93%~68. 80%, 0.87%~17. 21%,-212.38%~8. 27% and 0%~15. 17%, respectively. Conclusions In the CyberKnife treatment of lung tumors, the volume and location of tumors exert significant impact on the discrepancies of the dose calculation results of different algorithms. The smaller tumor volume and longer beam heterogeneity path are likely to generate a greater discrepancy. It is recommended to adopt or refer to the calculation results of Monte Carlo algorithm to deliver corresponding treatment.

Validation of a rapid method for synchrony tracking precision detection for the CyberKnife system / 中华放射医学与防护杂志

Objective To establish a rapid synchrony tracking precision detection method for the CyberKnife system by comparing the data between experimental measurements and end to end (E2E) result.Methods The auto quality assurance (AQA) phantom was placed on the synchrony motion plat and irradiated by two orthogonal beams.The concentricity of the beam projection center on the film and the wolfram center were analyzed through AQA software to detect tracking precision.The planning implement time of experimental measurements and E2E was then compared.Results No significant difference was found between the measurement and E2E data (P ＞ 0.05).The time for setting up and modeling in two approaches was identical and the average time for planning implement was 144 and 723 s,respectively.Conclusions The method in our analysis could reduce the procedure time and supplement the AQA and synchrony E2E test,which might be conducted in the morning quality assurance (QA) or weekly QA for CyberKnife system.

Influence of different cultivation measures on the content of three free carbohydrates of Codonopsis Radix / 中国中药杂志

To provide a scientific evidence for the quality control of Codonopsis Radix, a method was established for determining the content of three free carbohydrates of Codonopsis Radix. The developed method showed good linearity. The calibration curves were linear within the range of 2.312 5-18.500 0 μg for sucrose, 1.500 0-12.000 0 μg for glucose, and 2.000 0-16.000 0 μg for fructose, resgectwely. The recoveries varied between 96.31%-101.8%. The method is simple, accurate and reproducible, and can be used for determining the content of sucrose, glucose and fructose of Codonopsis Radix. The results showed that different cultivation measures had an effect on the content of three free carbohydrates of Codonopsis Radix. According to the content of sucrose, using Zhuanggenling>not using Zhuanggenling. While, not pinching, shelving>not pinching, not shelving>pinching, not shelving>pinching, shelving. According to the content of glucose and fructose, not using Zhuanggenling>using Zhuanggenling. While, pinching, shelving>not pinching, not shelving>not pinching, shelving>pinching, not shelving. In consideration of the differences of sweetness and content of the three free carbohydrates in Codonopsis Radix, we recommend that the content of free carbohydrates could be considered as the marker to evaluate the quality of Codonopsis Radix.

Mechanism of treatment effect of Huanglian-Huangqin herb pairs on cerebral ischemia rats based on metabolomic approach / 中国中药杂志

The metabolic effect of Huanglian-Huangqin herb pairs on cerebral ischemia rats was studied by using metabolomic method. The rat model of ischemia reperfusion injury induced by introduction of transient middle cerebral artery occlusion (MCAO) followed by reperfusion. Ultra high performance liquid chromatography-series four pole time of flight mass spectrometry method（UPLC-Q-TOF/MS）, Markerlynx software, and principal component analysis and partial least-squares discriminant analysis were used to analyze the different endogenous metabolites among the urine samples of sham rats, cerebral ischemia model rats, Huanglian groups (HL), Huangqin groups (HQ) and Huanglian-Huangqin herb pairs groups (LQ) was achieved, combined with accurate information about the endogenous metabolites level and secondary fragment ions, retrieval and identification of possible biological markers, metabolic pathway which build in MetPA database. The 20 potential biomarkers were found in the urine of rats with cerebral ischemia, which mainly involved in the neurotransmitter regulation, amino acid metabolism, energy metabolism, lipid metabolism and so on. Those metabolic pathways were disturbed in cerebral ischemia model rats, the principal component analysis showed that the normal and cerebral ischemia model is clearly distinguished, and the compound can be given to the normal state of change after HL, HQ, LQ administration. This study index the interpretation of cerebral ischemia rat metabolism group and mechanism, the embodiment of metabonomics can reflect the physiological and metabolic state, which can better reflect the traditional Chinese medicine as a whole view, system view and the features of multi ingredient synergistic or antagonistic effects.

A Ratiometric Fluorescence Sensing for Carboxylesterase Based on Semiconducting Polymer Quantum Dots / 分析化学

A carboxylesterase ( CaE ) ratiometric fluorescent probe based on semiconducting Poly ( 9 , 9-dioctylfluorenyl-2,7-diyl) (PFO) polymer quantum dots (Pdots) was prepared. The negatively charged PFO Pdots and the positively charged polyethyleneimine ( PEI) formed a nanocomposite Pdots@PEI by electrostatic interaction, and emitted fluorescence at 440 nm and 467 nm. In the presence of CaE, the substrate fluorescein diacetate ( FDA ) was hydrolyed into negatively charged fluorescein molecule, and could get closer to the positively charged Pdots@PEI due to electrostatic interactions, which could induce resonance energy transfer, resulting in the energy donor Pdots@ PEI fluorescence intensity gradually weakened and the fluorescence intensity of the FDA hydrolysis product increased. Based on the fluorescence intensity ratio of Pdots@PEI and the fluorescence enhancement of FDA hydrolysis products, a new method for selective detection of CaE was established. Under the optimal conditions, the linear range of the method on CaE testing was 0. 75-50 U/L with detection limits of 0 . 75 U/L ( S/N=3 ) . This method was used for the detection of the content of CaE in rabbit blood with satisfactory results.

Effect of density heterogeneity on absorbed dose with CyberKnife Synchrony Respiratory Tracking System / 中华放射肿瘤学杂志

Objective To measure the actual absorbed dose of the target in the QUASAR Respiratory Motion Phantom using the CyberKnife Synchrony Respiratory Tracking System, and to evaluate the effect of density heterogeneity on the absorbed dose of tumor gross target volume ( GTV ) . Methods Nine groups were obtained by making different patterns of QUASAR phantom:rib thickness of 0, 20, and 50 mm, and motion amplitudes of 0, 10, and 15 mm. The nine groups were treated with static computed tomography (CT) in different time phases of four-dimensional CT (4DCT) plan, with the same beam and number of monitor units, and the 4D accumulated dose was calculated. The doses of static and 4D plans were calculated using Ray-tracing and Monte Carlo algorithms, and the absorbed doses of GTV in the nine groups were measured at the same time. Results There were a decrease in calculated absorbed dose of GTV and an increase in deviation between the planned and actual dose, with the increases in simulated rib thickness and motion amplitude. Conclusions The density heterogeneity has an impact on the absorbed dose of GTV. Both static CT and 4DCT plan can evaluate the absorbed dose of GTV in case of small rib thickness and motion amplitude, and 4DCT plan with Monte Carlo algorithm may be the optimal method for evaluation of the absorbed dose of GTV in case of large rib thickness and motion amplitude ( deviation<3%)