Objective On the premise of meeting the image quality requirements of simulated location for pediatric radiotherapy,the simulated localizable CT parameters are optimized through phantom scanning to reduce the radiation dose.Methods CatPhan700 phantom was used to simulate the child's body,Philip 24-row large-aperture spiral simulated localizable CT was performed,and the CT images were obtained by scanning the phantom at different mAs and tube voltages.The mAs range was set at 60-400 mAs,the scanning was performed every 20 mAs interval,and the kV was set at 80,100,and 120 kV.Image evaluation was carried out using parameters such as image noise(N10 and mean SD),uniformity,low contrast resolution,high contrast resolution,and the stabilities of HU values of Air,Acrylic,50%bone,LDPE,20%bone,Teflon,Polystyrene,DelrinTM,Lung,PMP and Water.The CTDIVol and DLP automatically calculated by the simulated localizable CT system were read to evaluate the radiation dose.Results At 100 kV,as mAs increased,both CTDI and DLP showed upward trends,and the fitting results were linear correlated,with slopes of 0.034 5 and 0.932 4.Image noise was decreased nonlinearly with the increasing mAs.When mAs increased from 60 to 140 mAs,N10 decreased from 0.25%to 0.14%,and SD reduced from 3.74 HU to 2.54 HU.When mAs reached 180 mAs or higher,N10 fluctuated between 0.1%and 0.12%,the mean SD fluctuated between 2.0 and 2.5 HU,and the downward trends obviously slowed down.When mAs increased from 60 to 200 mAs,the low contrast resolution of the image dropped from 0.53 to 0.29.The image uniformity,high contrast resolution and HU values of different substances were less affected by mAs.The image quality of 100 kV and 200 mAs scanning was close to that of 120 kV scanning,but the image quality of 80 kV scanning failed to meet the clinical requirements.Conclusion In order to reduce the radiation dose as much as possible,the mAs should be set at 200 mAs when the tube voltage is set at 100 kV for a simulated cylinder with a diameter of 20 cm.In the actual simulation scanning for pediatric radiotherapy,the scanning parameters should be fine-tuned according to the phantom results and the actual physical characteristics of children to satisfy the optimization principle for radiation protection.

Objective:To verify the feasibility of using Elekta accelerated go live (AGL) standard process for the acceptance of multiple accelerators.Methods:The beams of three accelerators were adjusted by PTW Beamscan three-dimensional water tank to reach the AGL standard. Dose verification was performed for three accelerators that met AGL standards. A simple field test example from Cancer Hospital Chinese Academy of Medical Sciences was used to compare the MapCheck 3 surface dose measurement results with the surface dose calculated by the same accelerator model. Images of 10 patients including head and neck, esophagus, breast, lung and rectum were randomly selected. volumetric-modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) treatment techniques were used for planning design, and the measured dose of ArcCheck was compared with the planned dose calculated by the same accelerator model. One-way ANOVA was used to statistically analyze the passing rates of two-dimensional and three-dimensional dose verification.Results:The 6 MV X-ray percentage depth dose at 10 cm underwater (PDD 10) of three accelerators was 67.45%, 67.36%, 67.47%, and the maximum deviation between the three accelerators was 0.11%. The 6 MV flattenting filter free (FFF) mode X-ray PDD 10 was 67.33%, 67.20%, 67.20%, and the maximum deviation between the three accelerators was 0.13%. All required discrete point doses on each energy 30 cm×30 cm Profile spindle of the three accelerator X-rays deviated less than ±1% from the standard data. Absolute γ analysis was performed on the results of MapCheck 3 two-dimensional dose matrix validation. Under the 10% threshold of 2 mm/3% standard, the average passing rate of the test cases in Cancer Hospital Chinese Academy of Medical Sciences was above 99%, and the difference was not statistically significant ( P>0.05). Absolute γ analysis was performed on the ArcCheck verification results. Under the 10% threshold, the pass rate of 2 mm/3% was all above 95%, the maximum average passing rate of the three accelerators with different energy and different treatment techniques was 0.28% (6 MV, VMAT), 0.19%(6 MV FFF, VMAT), 0.56% (6 MV, IMRT) and 0.05% (6 MV FFF, IMRT), and the difference was not statistically significant ( P>0.05). Conclusion:Compared with traditional accelerator acceptance process, the acceptance time of each accelerator is shortened by 4-6 weeks by using the AGL standard process, and the radiotherapy plan of patients can be interchangeably executed among different accelerators.

Objective:To investigate a time series deep learning model for respiratory motion prediction.Methods:Eighty pieces of respiratory motion data from lung cancer patients were used in this study. They were divided into a training set and a test set at a ratio of 8∶2. The Informer deep learning network was employed to predict the respiratory motions with a latency of about 600 ms. The model performance was evaluated based on normalized root mean square errors (nRMSEs) and relative root mean square errors (rRMSEs).Results:The Informer model outperformed the conventional multilayer perceptron (MLP) and long short-term memory (LSTM) models. The Informer model yielded an average nRMSE and rRMSE of 0.270 and 0.365, respectively, at a prediction time of 423 ms, and 0.380 and 0.379, respectively, at a prediction time of 615 ms.Conclusions:The Informer model performs well in the case of a longer prediction time and has potential application value for improving the effects of the real-time tracking technology.

OBJECTIVE: To explore the genetic basis for a patient with Alport syndrome (AS) and confirm the existence of a splicing variant. METHODS: An AS patient diagnosed at the Affiliated Hospital of Inner Mongolia Medical University on January 8, 2021 for significant proteinuria and occult hematuria was selected as the study subject. Clinical data was collected. Peripheral blood samples were collected for the extraction of genomic DNA. Whole exome sequencing and Sanger sequencing were carried out to identify potential genetic variants. An in vitro experiment was also conducted to verify the abnormal mRNA splicing. Bioinformatic software was used to analyze the conservation of amino acids of the variant sites and simulate the 3D structure of the variant collagen IV protein. Immunofluorescence and immunohistochemistry were carried out on renal tissues from the patient to confirm the presence of AS kidney injury. RESULTS: The patient, a 21-year-old male, had a 24-hour urine protein of 3.53 g/24 h, which fulfilled the diagnostic criteria for proteinuria. His blood uric acid has also increased to 491 μmol/L. DNA sequencing revealed that he has harbored a c.835-9T>A splice variant of the COL4A5 gene, which was not found in either of his parents. In vitro experiment confirmed that the variant has removed 57 bp from the exon 15 of the mRNA of the COL4A5 gene. The deletion may cause loss of amino acid residues from positions 279 to 297, which in turn may affect the stability of the secondary structure of the α5 chain encoded by the COL4A5 gene. The amino acids are conserved across various species. The result of homology modeling indicated that the trimerization of Col-IV with the mutated α5 chain could be achieved, however, the 3D structure was severely distorted. The AS kidney damage was confirmed through immunofluorescence assays. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.835-9T>A variant was classified as likely pathogenic (PVS1_Moderate+PS3_Moderate+PM2_Supporting+PS2+PP3+PP4). CONCLUSION The c.835-9T>A variant of the COL4A5 gene probably underlay the AS in this patient. In vitro experiment has confirmed the abnormal splicing caused by the variant. Histopathological examination of the kidney tissue has provided in vivo evidence for its pathogenicity. Above finding has expanded the mutational spectrum of the COL4A5 gene.
Humans ; Male ; Young Adult ; Amino Acids ; China ; Collagen Type IV/genetics* ; Exons ; Nephritis, Hereditary/genetics* ; RNA Splicing

Objective To analyze the distribution features of the Bragg peak of carbon ion beams in materials using SRIM software, and to explore the use of computed tomography (CT) number to calculate the incident energy of carbon ion beams. Methods SRIM software was used to study the travel of carbon ion beams (100 to 300 MeV/u) in different equivalent materials, and analyze the effects of the incident energy of carbon ion beams and the type and thickness of equivalent materials on the depth of the Bragg peak of carbon ion beams. Origin 2017 was used to analyze the functional relationship between CT number and water-equivalent Bragg peak depth ratio (Di) through data fitting. Results The ratios of the Bragg peak depths in equivalent materials to that in water almost stayed constant with the increase in the incident energy of carbon ion beams. Through the functional relation between CT number and D_i, the Bragg peak depth of a carbon ion beam of a given energy in an equivalent material could be converted to the equivalent Bragg peak depth in water. Conclusion With the water-equivalent Bragg peak depth ratio D_i and CT number of different volume units of human tissues, the equivalent Bragg peak depth in water required for the Bragg peak to fall in the tumor can be accurately calculated, which can be used to reversely infer the needed incident energy of carbon ion beams.

OBJECTIVE: To explore the genetic etiology of a fetus with Cornelia de Lange syndrome type 1. METHODS: Clinical data of the fetus was collected. Genomic DNA was extracted from amniotic fluid and peripheral blood samples of the parents and subjected to low-depth copy number variant sequencing, whole exome sequencing (WES) and Sanger sequencing. Pathogenicity of the candidate variant was predicted based on the guidelines of American College of Medical Genetics and Genomics (ACMG). Minigene assay was used to assess the effect of the variant on mRNA splicing. RESULTS: WES revealed that the fetus has harbored a heterozygous c.5808+5gG>A variant in the intron of the NIPBL gene, which was predicted to affect the mRNA splicing. The same variant was not detected in either parent. The variant was not recorded in ExAC, 1000G and dbSNP databases. Comprehensive analysis showed that the variant was deleterious and may result in skipping of exon 31 during mRNA splicing. CONCLUSION The fetus was diagnosed with Cornelia de Lange syndrome type 1. Splicing variant identified by WES may be verified by minigene assay in vitro, which can provide more evidence for the prediction of its pathogenicity.
Cell Cycle Proteins/genetics* ; De Lange Syndrome/genetics* ; Female ; Fetus ; Humans ; Mutation ; Pregnancy ; Prenatal Diagnosis ; RNA, Messenger

Objective:To investigate the effects of of anti tumor necrosis factor-α (TNF-α) in adjuvant treatment of strangulated intestinal obstruction combined with ischemic intestinal necrosis.Methods:From February 2011 to August 2016 in Huadu District People′s Hospital Affiliated with Southern Medical University, 122 patients with strangulated intestinal obstruction combined with ischemic intestinal necrosis were selected and were equally divided into the experimental group and control group with 61 cases in each group according to the random draw envelope principle. Conventional surgical resection and anastomosis was used in control group, the postoperative anti TNF-α therapy was given for 2 weeks based on the treatment in control group.Results:All patients completed surgery and there were no serious complications during operation.The postoperative anal exhaust time and symptom remission time in experimental group were significantly lower than those in control group: (2.14 ± 0.41) d vs. (6.24 ± 1.28) d and (3.54 ± 0.77) d vs. (6.99 ± 0.91) d ( P<0.05). The incidence of postoperative 14 d complications such as anastomotic leakage, wound infection, anastomotic stenosis and pulmonary infection in the experimental group was 4.9%(3/61), and that of the control group was 18%(11/61), and the incidence of postoperative complications in the experimental group was significantly lower than that in the control group ( P<0.05). The postoperative 1d and 7 d serum TNF-α content in the experimental group was significantly lower than that in the control group ( P<0.05). The postoperative 14 d anal function in the experimental group was significantly better than that in the control group ( P<0.05). MRASP and MSP of postoperative 14 d in experimental group were all significantly higher than those in the control group: (80.24 ± 11.39) mmHg (1 mmHg=0.133 kPa) vs. (76.24 ± 12.11) mmHg, (231.98 ± 45.29) mmHg vs. (226.39 ± 41.87) mmHg ( P<0.05). Conclusions:The anti TNF-α in adjuvant treatment of strangulated intestinal obstruction combined with ischemic intestinal necrosis can promote the recovery of clinical symptoms and inhibit the release of TNF-α. It also can reduce the incidence of postoperative complications and improve gastrointestinal motility of patients.

Objective:To explore the clinical characteristics and establish a corresponding prognostic scoring model in patients with early-stage clinical features of hepatitis B-induced acute-on-chronic liver failure (HBV-ACLF).Methods:Clinical characteristics of 725 cases with hepatitis B-related acute-on-chronic hepatic dysfunction (HBV-ACHD) were retrospectively analyzed using Chinese group on the study of severe hepatitis B (COSSH). The independent risk factors associated with 90-day prognosis to establish a prognostic scoring model was analyzed by multivariate Cox regression, and was validated by 500 internal and 390 external HBV-ACHD patients.Results:Among 725 cases with HBV-ACHD, 76.8% were male, 96.8% had cirrhosis base,66.5% had complications of ascites, 4.1% had coagulation failure in respect to organ failure, and 9.2% had 90-day mortality rate. Multivariate Cox regression analysis showed that TBil, WBC and ALP were the best predictors of 90-day mortality rate in HBV-ACHD patients. The established scoring model was COSS-HACHADs = 0.75 × ln(WBC) + 0.57 × ln(TBil)-0.94 × ln(ALP) +10. The area under the receiver operating characteristic curve (AUROC) of subjects was significantly higher than MELD, MELD-Na, CTP and CLIF-C ADs( P < 0.05). An analysis of 500 and 390 cases of internal random selection group and external group had similar verified results. Conclusion:HBV-ACHD patients are a group of people with decompensated cirrhosis combined with small number of organ failure, and the 90-day mortality rate is 9.2%. COSSH-ACHDs have a higher predictive effect on HBV-ACHD patients' 90-day prognosis, and thus provide evidence-based medicine for early clinical diagnosis and treatment.

Objective: To explore the correlation between microdamage in white matter and radiotherapy dose at early stage after radiotherapy (RT) in patients with nasopharyngeal carcinoma (NPC). Methods: Thirty-three patients who were initially diagnosed with NPC were recruited and received diffusion tensor imaging (DTI) scan and neuro-cognitive scale test within 1 week before RT and the first day after RT. DTI-related characteristic parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (λ_‖), and radial diffusivity (λ_⊥) were calculated based on whole-brain voxel analysis method. Paired t-test was conducted to evaluate statistical significance between pre-RT and post-RT groups. In the subgroup analysis, all the subjects were divided into 3 groups according to the average dose of temporal lobe, and each group was set with an equal dose interval range. The DTI-related parameters of whole brain pre-RT and post-RT in each group were statistically compared. All the statistical results were corrected by FDR with a threshold of P<0.05 and clusters>100. Results: FA, MD, λ_‖ and λ_⊥in the post-RT group significantly differed compared with those in the pre-RT group (P<0.05). The values of FA, MD, λ_‖ and λ_⊥were 0.455±0.016, (9.893±0.403)×10^-4, (13.441±0.412)×10^-4 and (8.231±0.429)×10^-4, respectively. Subgroup analysis showed that the extent and degree of λ_‖ and λ_⊥ changes were exacerbated with the increase of the average dose of temporal lobe after RT. Particularly in high-dose group, the average dose range was 25-35 Gy and the extent of regions with significant changes was significantly larger than those in the medium-dose (15-25 Gy) and low-dose groups (5-15 Gy)(P<0.05). Conclusions DTI can be utilized to detect" normal" brain tissue microdamage in NPC patients at early stage after RT. The average radiation dose of temporal lobe may be one of the reasons for the severity of cerebral microdamage. In the future, DTI technique may be useful for guiding exposure dose of organs at risk during RT planning and to evaluate the cohort with a high risk of cerebral microdamage at early stage after RT, thereby protecting normal cerebral tissues to the maximum extent.

Objective: To compare the efficacy of different decompressions treatment combined with posterior cervical fusion and internal fixation treatment on Chiari I malformation associated with syringomyelia and atlantoaxial instability. Methods: From January 2016 to October 2017, 36 cases of Chiari I malformation associated with syringomyelia and atlantoaxial instability in Linfen People's Hospital were selected in the research.The patients were divided into two groups according to random number table method, with 18 cases in each group.The observation group was given decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment.The control group was given traditional decompression of posterior fossa + posterior cervical fusion and internal fixation treatment.The efficacy, complications occurred within 1 year after operation, JOA score and spinal cord cavity size at different time points before and after operation of the two groups were compared. Results: The total effective rate of the observation group [94.44%(17/18)] was slightly higher than that of the control group [88.89%(16/18)] (χ²=1.957, P>0.05). The total effective rate of the observation group at 1 year after operation was 88.89%(16/18), which was significantly higher than that of the control group [72.22%(13/18)] (χ²=3.498, P<0.05). The incidence rate of complications of the observation group at 1 year after operation was 11.11%(2/18), which was significantly lower than that of the control group [38.89%(7/18)](χ²=11.685, P<0.05). The JOA scores at discharge[(15.97±1.25)point] and 1 year after operation[(15.53±1.19)point] of the observation group were significantly higher than those of the control group[(14.21±1.18)point, (14.06±1.15)point](t=3.815, 3.706, all P<0.05). The spinal cord cavity size at discharge [(2.13±0.64)mm] and 1 year after operation[(2.28±0.69)mm] of the observation group were significantly higher than those of the control group [(3.41±0.76)mm, (3.45±0.78)mm](t=5.743, 5.511, all P<0.05). Conclusion The long-term efficacy of decompression of posterior fossa of small bone window + cerebellar tonsillectomy + posterior cervical fusion and internal fixation treatment on Chiari I malformation associated with syringomyelia and atlantoaxial instability is remarkable, the recovery of spinal cord function and syringomyelia is well and the postoperative complications incidence is relatively low, which is worthy of popularization and application.