Application of a novel modified Blumgart anastomosis in laparoscopic pancreaticoduodenectomy / 中国医师进修杂志

Objective:To investigate the efficacy and safety of a novel modified Blumgart pancreaticojejunostomy in laparoscopic pancreaticoduodenectomy (LPD).Methods:Between May 2021 and January 2022, 13 successive cases from Lihuili Hospital Affiliated to Ningbo University who underwent LPD were enrolled in this retrospective study. The study retrospectively analyzed the demographic characteristics, perioperative outcomes, and pathological results of these cases.Results:Twenty patients underwent LPD success-fully and one required conversion to open surgery. The operative time was (308.6 ± 61.7) min. The duration for PJ was (26.7 ± 4.3) min. The estimated blood loss was (188.1 ± 94.2) ml. The postoperative hospital stay was (14.2 ± 3.5) d. There was one case of biochemical leakage and no case of grade B or grade C pancreatic fistula.Conclusions:The new method is safe, simple and feasible. The novel method could reduce the incidence of pancreatic fistula and other complications after LPD.

Study the change of serum osteosclerotin and Dickkopf-3 expression in elderly patients with intertrochanteric fracture / 中国医师进修杂志

Objective:To investigate the changes of perioperative serum osteosclerosis protein (SOST) and Dickkopf-3 (Dkk-3) in elderly patients with femoral intertrochanteric fracture.Methods:Thirty elderly patients who underwent reduction and fixation of femoral intertrochanteric fracture in Baoding Second Hospital from May 2017 to December 2017 were prospectively selected as the observation group; 30 healthy subjects in the same period were selected as the healthy control group. Enzyme linked immunosorbent assay (ELISA) was used to detect the expression of serum SOST and Dkk-3 at 1 d before operation and at 1, 3, 5 d after operation and compared with the same period of healthy physical examination(normal control group). Spearman rank correlation analysis was used to analyze the correlation between SOST and Dkk-3 and disease activity score (ASDAS) and spinal imaging evaluation score (mSASSS).Results:There was a positive correlation between Dkk-3 level and ASDAS score in the observation group ( r = 0.331, P = 0.012); the level of SOST was negatively correlated with the scores of ASDAS ( r = - 0.162, P = 0.017). The levels of serum SOST and Dkk-3 in the observation group were lower than those in the healthy control group: 1.29(1.00, 2.40) μg/L vs. 1.96(1.63, 2.65) μg/L, (6.11 ± 1.15) μg/L vs. (9.81 ± 1.76) μg/L, P<0.05. The levels of serum SOST and Dkk-3 in the observation group increased first and then decreased on the 1st, 3rd and 5th day after operation. The level of serum Dkk-3 increased to the highest level on the 3rd day after operation, and then decreased gradually, but it was still slightly higher than that before operation. The level of serum SOST in the observation group increased to the highest level 1st day after operation, and decreased at 3rd and 5th day after operation. The perioperative serum levels of SOST and Dkk-3 in the observation group were positively correlated, the correlation coefficient was the largest at 1 day after operation ( r = 0.571) and the lowest before operation ( r = 0.119). Conclusions:The perioperative serum levels of SOST and Dkk-3 in elderly patients with femoral intertrochanteric fracture increased first and then decreased. The change of serum SOST level is more sensitive and can be used as a sensitive index to reflect the change of osteogenic ability.

Mechanisms of cholesterol metabolism imbalance in a PA-induced non-alcoholic fatty liver disease cell model / 中国药科大学学报

@#Liver cholesterol metabolism disorder plays an important role in the development of non-alcoholic fatty liver disease (NAFLD).In order to reveal the molecular mechanism of cholesterol homeostasis imbalance induced by saturated fatty acids, HepG2 cells were stimulated with palmitic acid (PA).Lipids accumulation was analyzed by Oil Red O staining, intracellular triglyceride and cholesterol quantification.The level of genes and proteins related to cholesterol homeostasis was measured by RT-qPCR and western blotting.Additionally, intracellular bile acids and mitochondrial oxysterols were detected by LC-MS/MS.The results demonstrated that intracellular lipids such as TG and TC were significantly increased in the model with PA stimulation.Although no significant difference was detected in genes related to cholesterol synthesis and uptake, the protein expression of ABCG5 and LXRα were significantly down-regulated, indicating a decrease in cholesterol efflux.Meanwhile, the gene expression of STARD1 and CYP7B1, which are responsible for bile acid alternative synthesis, were markedly enhanced, along with a significant increase of cholesterol and 27-OHC in mitochondria and CDCA in cells.These results suggested that PA overload may disrupt cholesterol homeostasis by inhibiting cholesterol efflux and promoting bile acids synthesis.

N6-Methyladenosine Methyltransferase METTL3 Alleviates Diabetes-Induced Testicular Damage through Modulating TUG1/Clusterin Axis

Background@#The present study investigated the regulatory effects of N6-methyladenosine (m6A) methyltransferase like-3 (METTL3) in diabetes-induced testicular damage. @*Methods@#In vivo diabetic mice and high glucose (HG) treated GC-1 spg cells were established. The mRNA and protein expressions were determined by real-time quantitative polymerase chain reaction, Western blot, immunofluorescence and immunohistochemistry staining. Levels of testosterone, blood glucose, cell viability, and apoptosis were detected by enzyme-linked immunosorbent assay, MTT, and flow cytometry, respectively. Molecular interactions were verified by RNA immunoprecipitation and RNA pull-down assay. Histopathological staining was performed to evaluate testicular injury. @*Results@#METTL3 and long non-coding RNA taurine up-regulated 1 (lncRNA TUG1) were downregulated in testicular tissues of diabetic mice and HG-treated GC-1 spg cells. METTL3 overexpression could reduce the blood glucose level, oxidative stress and testicular damage but enhance testosterone secretion in diabetic mouse model and HG-stimulated GC-1 spg cells. Mechanically, METTL3-mediated m6A methylation enhanced the stability of TUG1, then stabilizing the clusterin mRNA via recruiting serine and arginine rich splicing factor 1. Moreover, inhibition of TUG1/clusterin signaling markedly reversed the protective impacts of METTL3 overexpression on HG-stimulated GC-1 spg cells. @*Conclusion@#This study demonstrated that METTL3 ameliorated diabetes-induced testicular damage by upregulating the TUG1/clusterin signaling. These data further elucidate the potential regulatory mechanisms of m6A modification on diabetes-induced testicular injury.

Progress in molecular signal pathway of dental fluorosis / 中华地方病学杂志

Dental fluorosis is a manifestation of chronic oral fluorosis caused by excessive fluoride intake in childhood. At present, the molecular mechanism of dental fluorosis is still unclear. Ameloblasts are the most sensitive cells to fluoride in tooth tissue. Fluoride affects the proliferation and secretion of ameloblasts through the role of key molecules in the molecular signal pathways, leading to the formation of dental fluorosis. This paper reviews the relationship between the molecular signal pathways [mitogen-activated protein kinase (MAPK), transforming growth factor-β (TGF-β)/Smad, Wnt, Foxo1/Runx2], stress pathways (endoplasmic reticulum stress and oxidative stress) and the occurrence of dental fluorosis in recent years, in order to deeply understand the pathogenesis of dental fluorosis at the molecular level, and provide new ideas for the prevention and treatment of dental fluorosis.

Establishment of prediction model for severe acute pancreatitis complicated with abdominal hypertension / 中华胰腺病杂志

Objective:To construct the prediction model of SAP complicated with intra-abdominal hypertension (IAH), and evaluate the prediction efficiency of the model.Methods:The clinical data of 322 SAP patients admitted to the emergency department of Cangzhou Hospital of Integrated Chinese and Western Medicine in Hebei Province from January 2017 to December 2021 were retrospectively analyzed. They were divided into IAH group ( n=153) and control group ( n=169) according to whether they had IAH complications or not. The clinical characteristics and laboratory test results of the two groups were compared. Multifactor logistic step-up regression was used to analyze the risk factors of SAP patients complicated with IAH. A nomogram model for predicting SAP complicated with IAH was established by using R software. The receiver operating characteristic curve (ROC) of the model was plotted, and the area under the curve (AUC) was calculated to evaluate its prediction efficiency. Calibration chart, Hosmer-Lemesshow test and decision curve analysis were used to evaluate the prediction accuracy and clinical application value of the model. The Bootstrap method was applied to verify the model internally. Results:In IAH group, cases with body mass index, CRP, procalcitonin (PCT), WBC, acute physiological and chronic health assessmentⅡ (APACHEⅡ) score, modified CT Severity Index score (MCTSI), incidence of complications (abdominal effusion, abdominal infection, gastrointestinal dysfunction, shock, multiple organ dysfunction syndrome), mechanical ventilation, the number of high-volume fluid reactivation (24 h≥4 L) were more than those in control group; serum albumin and serum calcium in IAH group were lower than those in control group, and the differences were statistically significant (all P value <0.05). Multivariate logistic regression analysis showed that serum albumin ( OR=0.815, 95% CI 0.710-0.937), CRP ( OR=1.005, 95% CI 1.002-1.008), MCTSI ( OR=2.043, 95% CI 1.695-2.463), complication of gastrointestinal dysfunction ( OR=4.179, 95% CI 2.170-8.049), and high-volume fluid resuscitation ( OR=4.265, 95% CI 2.269-8.015) were independent risk factors for IAH in SAP.The Nomogram prediction model was established using the five factors above as parameters, and the AUC value for predicting IAH complication was 0.886. The Hosmer-Lemesshow test showed a high consistency between the prediction results and the actual clinical observation results ( P=0.189). The results of decision curve analysis showed that the prediction probability of the model was between 10% and 85%, which could bring more benefits to patients. Conclusions:The early prediction model of SAP with concurrent IAH is successfully established, which can better predict the risk of SAP with concurrent IAH.

Elevated Levels of Naturally-Occurring Autoantibodies Against the Extracellular Domain of p75NTR Aggravate the Pathology of Alzheimer's Disease / 神经科学通报·英文版

The extracellular domain (p75ECD) of p75 neurotrophin receptor (p75NTR) antagonizes Aβ neurotoxicity and promotes Aβ clearance in Alzheimer's disease (AD). The impaired shedding of p75ECD is a key pathological process in AD, but its regulatory mechanism is largely unknown. This study was designed to investigate the presence and alterations of naturally-occurring autoantibodies against p75ECD (p75ECD-NAbs) in AD patients and their effects on AD pathology. We found that the cerebrospinal fluid (CSF) level of p75ECD-NAbs was increased in AD, and negatively associated with the CSF levels of p75ECD. Transgenic AD mice actively immunized with p75ECD showed a lower level of p75ECD and more severe AD pathology in the brain, as well as worse cognitive functions than the control groups, which were immunized with Re-p75ECD (the reverse sequence of p75ECD) and phosphate-buffered saline, respectively. These findings demonstrate the impact of p75ECD-NAbs on p75NTR/p75ECD imbalance, providing a novel insight into the role of autoimmunity and p75NTR in AD.

Application of project-based learning in clinical teaching of radiation physics for radiotherapy residents / 中华放射肿瘤学杂志

Objective:To observe the effect of project-based learning (PBL) in the clinical teaching of radiation physics.Methods:Thirty-two residents specializing in radiotherapy were included in the study. In the experimental group ( n=16), PBL was adopted, while traditional clinical teaching method was employed in the control group ( n=16). After the rotation, the assessment was conducted, as well as a questionnaire survey was performed, including five aspects: overall satisfaction, understanding of radiation physics knowledge, learning motivation, learning burden, and learning efficiency. Results:The assessment score in the experimental group was 86.31±5.41, which was higher than 75.28±5.91 in the control group, and the difference was statistically significant. Residents in the experimental group were satisfied with the effect of PBL.Conclusion:Compared with the traditional teaching method, PBL can improve the learning motivation, efficiency, and performance of radiotherapy residents, which is highly recognized by the residents.

Radiation shielding for the intraoperative radiotherapy using low energy X-rays / 中华放射医学与防护杂志

Objective:To assess the shielding requirements of low energy X-ray intraoperative radiotherapy room under the domestic and foreign standards and guidelines, to measure the sured transmission factors for a range of shielding materials, the ambient dose equivalent rate around concerned positions and the shielding effect of protective devices, so as to provide references for shielding design of such radiotherapy units and applications of radiological protection devices.Methods:The required shielding thicknesses for a treatment room with INTRABEAM intraoperative radiotherapy system were calculated under the Chinese national standard GBZ 121, IPEM report No. 75 and NCRP report No. 151, respectively. The transmission factors for a range of shielding materials including solid water slab, shielding sheet and shielding apron were measured. Moreover, the ambient dose equivalent rates were measured under the simulated working conditions and the shielding effectiveness of a lead screen was evaluated.Results:The required lead thicknesses calculated under different standards and guidelines were less than 0.6 mm for all the concerned points, with the differences at sub-millimeter level. The low energy X-rays generated by this equipment attenuated rapidly in the shielding materials. The measured transmission factors of 0.05 mm lead equivalent shielding sheet and 0.25 mm lead equivalent shielding apron were 0.068 and 0.003 8, respectively. When the radiation was delivered using spherical applicator without any attenuation, the ambient dose equivalent rates at 1 m and 2 m from the X-ray source were 10.7 and 2.6 mSv/h, respectively. The corresponding measurement values decreased to 3.8 and 0.9 μSv/h, respectively, when the spherical applicator was inserted into a small water tank. Meanwhile, the ambient dose equivalent rate at 2 m was reduced to the background level when using protective screen.Conclusions:The shielding requirements for a low energy X-ray intraoperative radiotherapy facility are minimal, with low effective energy of X-rays generated by this equipment, but the dose rate close to the unshielded radiation source is high. The shielding scheme of treatment room should be optimized in design and the protective device should be used in a reasonable way.

Preoperative prediction of Ki-67 expression status in breast cancer based on dynamic contrast enhanced MRI radiomics combined with clinical imaging features model / 中华放射学杂志

Objective:To investigate the value of preoperative prediction of Ki-67 expression status in breast cancer based on multi-phase enhanced MRI combined with clinical imaging characteristics prediction model.Methods:This study was retrospective. A total of 213 breast cancer patients who underwent surgical treatment at Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between June 2016 and May 2017 were enrolled. All patients were female, aged 24-78 (51±10) years, and underwent routine breast MRI within 2 weeks prior to surgery. According to the different Ki-67 expression of postoperative pathological results, patients were divided into high expression group (Ki-67≥20%, 153 cases) and low expression group (Ki-67<20%, 60 cases). The radiomic features of breast cancer lesions were extracted from phase 2 (CE-2) and phase 7 (CE-7) images of dynamic contrast enhanced (DCE)-MRI, and all cases were divided into training and test sets according to the ratio of 7∶3. The radiomic features were first selected using ANOVA and Wilcoxon signed-rank test, followed by the least absolute shrinkage and selection operator method regression model. The same method of parameters selection was applied to clinical information and conventional imaging features [including gland classification, degree of background parenchymal enhancement, multifocal/multicentric, lesion location, lesion morphology, lesion long diameter, lesion short diameter, T 2WI signal characteristics, diffusion-weighted imaging (DWI) signal characteristics, apparent diffusion coefficient (ADC) values, time-signal intensity curve type, and axillary lymph nodes larger than 1 cm in short axis]. Support vector machine (SVM) was then used to construct prediction models for Ki-67 high and low expression states. The predictive performance of the models were evaluated using receiver operating characteristic (ROC) curves and area under cueve(AUC). Results:Totally 1 029 radiomic features were extracted from CE-2 and CE-7 images, respectively, and 9 and 7 best features were obtained after selection, respectively. And combining the two sets of features for a total of 16 features constituted the CE-2+CE-7 image best features. Five valuable parameters including lesion location, lesion short diameter, DWI signal characteristics, ADC values, and axillary lymph nodes larger than 1 cm in short axis, were selected from all clinical image features. The SVM prediction models obtained from the radiomic features of CE-2 and CE-7 images had a high AUC in predicting Ki-67 expression status (>0.70) in both the training set and the test set. The models were constructed by combining the CE-2, CE-7, and CE-2+CE-7 radiomic features with clinical imaging features, respectively, and the corresponding model performance in predicting Ki-67 expression status was improved compared with the models obtained by using the CE-2, CE-7, and CE-2+CE-7 radiomic features alone. The SVM prediction model obtained from CE-2+CE-7 radiomic features combined with clinical imaging features had the best prediction performance, with AUC of 0.895, accuracy of 84.6%, sensitivity of 87.9%, and specificity of 76.2% for predicting Ki-67 expression status in the training set and AUC of 0.822, accuracy of 70.3%, sensitivity of 76.1%, and specificity of 55.6% in test sets.Conclusion:The SVM prediction model based on DCE-MRI radiomic features can effectively predict Ki-67 expression status, and the combination of radiomic features and clinical imaging features can further improve the model prediction performance.

Molecular mechanism of fluoride toxicity to ameloblasts based on bioinformatics method / 中华地方病学杂志

Objective:To explore the molecular mechanism of fluoride toxicity to ameloblasts.Methods:Mouse ameloblast cell line (LS8 cells) was taken and divided into control group [0.0 mmol/L sodium fluoride (NaF)] and fluoride exposed group (1.6 mmol/L NaF) according to the final concentration of NaF. Transcriptome sequencing was performed to screen differentially expressed genes (DEGs), and gene ontology (GO) analysis and gene set enrichment analysis (GSEA) were performed on DEGs. The STRING database was used to construct the protein-protein interaction (PPI) network of DEGs, and Cytoscape 3.8.0 software was used to visualize the PPI network to screen key modules and key genes. At the same time, real-time fluorescence quantitative PCR was used to detect the mRNA expression level of key genes, and the key genes were verified by gene expression database (GEO database).Results:Compared with the control group, there were 709 DEGs in the fluoride exposed group, including 223 up-regulated genes and 486 down-regulated genes. The GO analysis of DEGs mainly involved molecular functions such as receptor-ligand activity, cell adhesion molecule binding, structural components of extracellular matrix, cellular components such as collagen of extracellular matrix, receptor complex, membrane raft, biological processes such as external packaging structure organization, extracellular structure organization, and extracellular matrix organization. The GSEA of the whole gene set found that the interleukin-17 (IL-17) signaling pathway, ribosome biogenesis in eukaryotes, and the nuclear factor kappa-B (NF-κB) signaling pathway were activated, while fatty acid degradation, pyruvate metabolism and fatty acid metabolism were inhibited. After constructing PPI network, three key modules and four key genes [typeⅠcollagen α1 (Col1a1), typeⅠcollagen α2 (Col1a2), typeⅤcollagen α1 (Col5a1) and fibrinogen 1 (Fbn1)] were obtained. Compared with the control group, the mRNA expression levels of Col1a1, Col1a2, Col5a1 and Fbn1 in LS8 cells of the fluoride exposed group were significantly decreased ( P < 0.05), which was consistent with the change trend of gene expression in the GEO database. Conclusion:Key genes such as Col1a1, Col1a2, Col5a1, Fbn1, and signaling pathways such as IL-17 and NF-κB, which are screened by bioinformatics method, may be closely related to the toxic effects of fluoride on ameloblasts.

Research progress on the prognostic value of the ratio of lymphocytes to C-reactive protein in digestive system neoplasms / 国际肿瘤学杂志

Tumor-associated inflammation is closely related to the development of tumors. The ratio of lymphocytes to C-reactive protein (LCR) is a new marker reflecting the inflammatory state of the body, which plays an important role in predicting the prognosis of digestive system neoplasms. Compared with the detection of lymphocytes or C-reactive protein alone, this marker has higher sensitivity and accuracy, and can provide a new direction for clinical diagnosis and treatment of digestive system neoplasms.

Progress of Lymphatic Navigation Technique in Minimally Invasive Surgery for Gastric Cancer / 肿瘤防治研究

The combination of standardized D2 lymph node dissection and lymph node sorting after surgery can improve the survival of patients with gastric cancer and increase the accuracy of staging. With the development of different lymphatic tracers, individualized lymphatic navigation has become a new technical breakthrough in minimally invasive surgery for gastric cancer. Lymph node tracing is an important method to improve the quality of intraoperative lymph node dissection and correct the postoperative pathological stage. This article reviews the application status and progress of lymphatic navigation technology.

Effects of the optimization and upgrading of auxiliary tools on transaxillary dual-plane breast augmentation / 中华医学美学美容杂志

Objective:To improve the multiple-link operation efficiency, effect and satisfaction of transaxillary dual-plane breast augmentation by optimizing and upgrading the configuration of auxiliary tools.Methods:From January 2019 to May 2021, breast augmentation was performed in 130 female patients (aged 32±8 years) in the Cosmetic and Plastic Center of the First Affiliated Hospital of Harbin Medical University. The study was conducted among 63 patients who were eligible for the criteria of high configuration surgery. 67 patients underwent standard configuration surgery. The average operation time, intraoperative blood loss, drainage volume (24 hours after operation), postoperative visual analog scale (VAS) pain score and satisfaction were statistically analyzed.Results:The data of high configuration method and standard configuration method were compared as follows: average operation time was (78.6±12.2) min / (93.1±12.1) min ( t=15.73, P<0.05); the average intraoperative blood loss was (3.1±1.0) ml / (14.4±3.5) ml ( t=13.83, P<0.05); the drainage volume (24 hours after operation) was (37.2±8.2) ml / (61.4±10.9) ml ( t=20.82, P<0.05); the pain score on the first day after surgery was (6.1±1.7) points / (7.5±1.6) points ( t=8.57, P<0.05). The overall satisfaction rate was 97.1±1.6 / 95.6±2.0 ( t=5.58, P>0.001), at 6 months after operation. No severe complications were found during the follow-up period, such as capsular contracture, hematoma, infection and double bubble deformity. Conclusions:The use of ultrasonic knife with delivery bag is an effective optimization and upgrade of the endoscopic assisted transaxillary dual plane breast augmentation. The advantages of this method are obvious, highly efficient, safe, effective and satisfactory. It is worthy of clinical application and promotion.

Disease-modifying therapy for multiply system atrophy / 中华老年医学杂志

Multiple system atrophy(MSA)is a rare and fatal neurodegenerative disease occurring in middle-aged and older people, mainly characterized by autonomic nervous system and motor dysfunction.At present, there is no effective method to prevent or reverse its progression, and its treatment is mostly symptom-based, with limited success.A large number of interventional trials have been conducted to explore new treatments for MSA, but there is no clearly effective disease-modifying therapy, probably as a result of poor understanding of the pathophysiological and physiological mechanisms underlying MSA, which may be influenced by multiple factors.The purpose of this paper is to review the existing intervention trials for disease modification therapy of MSA and to discuss the outlook for new therapeutic targets.

Statistical analysis of duration of each phase of Unity MR-linac in clinical application / 中华放射肿瘤学杂志

Objective:To analyze the duration of each phase of Unity MR-linac in clinical application, aiming to provide reference for clinical optimization of the process time.Methods:Clinical data of 55 patients treated with Unity MR-linac were retrospectively analyzed. All patients were divided into the adapt to position (ATP) and adapt to shape (ATS) groups according to the planning method. The duration of each phase in the treatment process, the name and the time of each sequence, the number of beams, segments and total monitor units (MUs) were recorded and compared between two groups. In addition, the set-up time was counted according to different treatment sites. The time of each sequence and set-up time were expressed as the median M (Q 1, Q 3), and the number of beams, segments and total MUs of each plan were described as the mean±SD. Results:42 patients underwent ATP with a total of 305 treatment sessions: setup time was 3(2, 5) min, MR scanning time was 5(4, 7) min, registration time was 3(3, 4) min, adaptive planning time was 8(4, 12) min, beam on time was 8(6, 11) min, and the total time was 30(25, 36) min. 13 patients received ATS with a total of 65 treatment sessions: setup time was 2(2, 3) min, MR scanning time was 7(5, 8) min, registration time was 4(3, 5) min, time of delineation of target and organs at risk was 12(9, 16) min, adaptive planning time was 11(10, 14) min, beam on time was 10(9, 11) min and the total time was 55(49, 61) min. The set-up time according to treatment sites was 4(2, 4) min in the head and neck, 2(2, 4) min in the chest, and 3(2, 5) min in the abdomen. The number of fields, segments and total MUs during ATP were 8.1±1.7, 49.9±31.2, 846.75±363.44 in the head and neck, 8.0±2.0, 60.7±13.3, 790.21±279.00 in the chest, and 9.7±2.0, 81.2±22.3, 2007.32±1053.81 in the abdomen, respectively. The number of fields, segments and total MUs during ATS in head and neck of one case were 13, 39, 993.07, and 9.5±1.5, 65.5±6.3, 2763.26±835.41 in the abdomen.Conclusions:MR-guided radiotherapy yields huge potential in clinical application. However, there is still much room for the improvement of shortening the process duration.

Clinical dosimetry commissioning of 1.5 T MR-linac / 中华放射肿瘤学杂志

Objective:To introduce the clinical dosimetry commissioning methods and results of the 1.5 T MR-linac.Methods:In May, 2019, an Elekta Unity 1.5 T MR-linac was installed in Cancer Hospital, Chinese Academy of Medical Sciences and dosimetry commissioning was performed with magnetic field compatible measuring instruments. Commissioning items include absolute dose calibration, data acquisition and planning system model verification.Results:Absolute dose calibration in magnetic field should be corrected by magnetic field correction factor. The standard output dose of Unity was 87 cGy. Gamma analysis (3%/2 mm) was performed on the beam collection data and the planning system calculation data. The average pass rate of dose verification of standard field test cases was 96.41%, and the TG119 test case was 98.24%. The IROC end to end test case was 97.5%(7%/4 mm).Conclusions:The planning system model and the beam collection data have good consistency. The dose verification results of the standard field and TG119 test cases meet the general tolerance limit requirements of the AAPM TG218 report, and the verification results of the IROC end-to-end test cases meet the IROC center standards.

The standard adapt-to-shape workflow for prostate cancer on MR-linac—Experience from National Cancer Institute/Cancer Hospital, Chinese Academy of Medical Sciences / 中华放射肿瘤学杂志

With aligned MR registration, the MR-Linac provides superior soft tissue resolution for prostate cancer. No fiducial markers or electromagnetic transponders insertion is needed to guarantee high-precision radiotherapy. The highly-recommended Adapt-To-Shape (ATS) workflow can resolve all the problems encountered during prostate cancer radiotherapy, including prostate volume changes and adjacent organs motion, both inter-fractionally and intra-fractionally. With all the above advantages, MR-Linac performs outstandingly than conventional linac in prostate cancer RT delivery, and probably helps us to reduce the CTV-PTV margin safely in the near future. Nevertheless, it is difficult to implement the ATS workflow in clinical practice. In this article, the standard ATS workflow for prostate cancer was summarized based on our own experience.

Preliminary application of MR-Linac in breast cancer radiotherapy in a single academic center / 中华放射肿瘤学杂志

Objective:To describe a prospective study of pre-operative tumor-bed boost performed at the 1.5 T MR-Linac in combination with adjuvant whole breast irradiation, and a first case, with an accentuation on clinical feasibility and safety.Methods:A phase II, single arm study recruiting early stage patients follows a paradigm that first boosts the tumor bed and then undergoes breast conservative surgery in 2 weeks, and last irradiates the whole breast in 6 weeks. The primary endpoint is ≥ grade 2 acute breast toxicity. A 43 years old patient affected by a breast carcinoma, not special type of the right-sided lateral quadrant, staged cT 2N 0M 0, was planned and treated. The dose, 8 Gy for one time, was calculated by Monaco on CT simulation images. Both the air electron stream effect (ESE) and the electron return effect (ERE) at the presence of 1.5 T magnetic field were evaluated. During the pre-treatment evaluation, we carried out adaptation-to-position adjustment. Results:The normal organ dosimetry is within toleration. The Dmax to the skin, the chin and the right upper arm was 8.44 Gy, 28.5 cGy and 17.8 cGy, respectively. There was no increased toxicity from ERE and ESE, and the treatment was well tolerated without > grade 1 acute toxicity. The patient received breast conservative surgery on day 7 without delayed wound healing.Conclusions:This is the first case successfully treated within a clinical trial by pre-operative tumor-bed boost under 1.5 T MR-Linac in our institution. More participants are needed to validate and optimize the paradigm.

Preliminary study of clinical application of magnetic resonance linear accelerator in liver malignancies / 中华放射肿瘤学杂志

Objective:To investigate the workflow, efficacy and safety of MR-Linac in liver malignancies.Methods:Clinical data of 15 patients with hepatocellular carcinomas (HCC) or liver metastases treated with MR-Linac between November 2019 and July 2021 were retrospectively analyzed. The workflow of MR-Linac was investigated and image identification rate was analyzed. Patients were followed up for response and toxicity assessment.Results:Fifteen patients (6 HCC, 8 liver metastases from colorectal cancer, 1 liver metastasis from breast cancer) were enrolled. A total of 21 lesions were treated, consisting of 10 patients with single lesion, 4 patients with double lesions and 1 patient with triple lesions. The median tumor size was 2.4 cm (0.8-9.8 cm). The identification rate for gross tumor volume (GTV) in MR-Linac was 13/15. Although GTV of two patients were unclearly displayed in MR-Linac images, the presence of adjacent blood vessel and bile duct assisted the precise registration. All the patients were treated with stereotactic body radiation therapy (SBRT). For HCC, the median fraction dose for GTV or planning gross tumor volume (PGTV) was 6 Gy (5-10 Gy) and the median number of fractions was 9(5-10). The median total dose was 52 Gy (50-54 Gy) and the median equivalent dose in 2 Gy fraction (EQD 2Gy) at α/ β= 10 was 72 Gy (62.5-83.3 Gy). For liver metastases, the median fraction dose for GTV or PGTV was 5 Gy (5-10 Gy) and the median number of fractions was 10(5-10). The median total dose was 50 Gy (40-50 Gy) and the median EQD 2Gy at α/ β=5 was 71.4 Gy (71.4-107.1 Gy). At 1 month after SBRT, the in-field objective response rate (ORR) was 8/13 and the disease control rate was 13/13. At 3-6 months after SBRT, the in-filed ORR was increased to 6/6. During the median follow-up of 4.0 months (0.3-11.6), 4-month local progression-free survival, progression-free survival and overall survival were 15/15, 11/15 and 15/15, respectively. Toxicities were mild and no grade 3 or higher toxicities were observed. Conclusions:MR-Linac provides a platform with high identification rates of liver lesions. Besides, the presence of adjacent blood vessel and bile duct also assists the precise registration. It is especially suitable for liver malignancies with promising local control and well tolerance.