Objective:To explore and compare the image quality and radiation dose between the spiral scanning and the axial scanning for skull phantom based on specific conditions.Methods:The position of the orbitomeatal base line(OBL)of the skull phantom was marked,and the different angles of elevation of skull were adjusted.The angles between OBL and bed surface were respectively set as 90°,100°,110° and 120°.The axial scanning and spiral scanning were respective adopted to conduct 24 times of image acquisition when the computed tomography dose index(CTDIvol)of fixed volume were respectively 40,50 and 60 mGy.The cross section of axial scanning was vertical to OBL,and the images of spiral scanning used the reconstructed technique of image quality enhancement(IQE)of removing spiral artifacts to conduct reconstruction along the OBL direction.The CT value(HU)and standard deviation(SD)of the bilateral cerebellum,temporal lobe,frontal lobe and parietal lobe of the phantom were measured,and the signal-to-noise ratio(SNR)of each lobe of the phantom was calculated.The CTDIvol and dose-length product(DLP)were recorded,and the effective dose(ED)of lens was calculated.Results:The differences of the SNR values of cerebellum and occipital lobe(R),cerebellum and occipital lobe(L),temporal lobe(R),temporal lobe(L),frontal lobe(R),frontal lobe(L),parietal lobe(R)and parietal lobe(L)between two kinds of scanning models were significant(F=6.48,5.83,7.00,6.20,7.30,8.26,5.72,5.83,P<0.05),respectively.There was significant difference in lens DLP between the two kinds of scanning models(F=10.96,P<0.05).The spiral scanning and IQE reconstructed technique were used to conduct image acquisition and processing.The SNR value of spiral scanning imaging was better than that of axial scanning,and the reconstructions of coronal and sagittal positions could be conducted,and the radiation doses of lens were similar,but the DLP value of spiral scanning was slightly higher than that of axial scanning at the same CTDIvol.Conclusion:Using the IQE reconstruction technique of spiral scanning can obtain satisfactory CT sectional images of skull under the situations that machine cannot change scanning angle or the scanning of axial position is unable to conduct cooperation.

Objective:To investigate the radiation dose and detection efficiency of artificial intelligence (AI) system for solid nodules in chest phantom with different scanning protocols.Methods:A total of 60 simulated nodules with different CT values and diameters were uniformly placed in each lung lobe and lung segment of the anthropomorphic chest phantom. GE Revolution evo CT was used to scan the chest phantom. 64 groups of images with different scanning parameters were collected at the tube voltage of 80, 100, 120, 140 kV, different noise indexes (NI 10-40 with interval 2), and other fixed parameters. The detection result of simulated nodules were recorded on AI software, and the detection rate and false detection rate were calculated, respectively, for different shapes of nodules. The mean volume CT dose index (CTDI vol) and dose length product (DLP) of each scan were recorded. Results:There were no statistically significant differences in the detection rate and false detection rate of spherical nodules and irregular nodules at different tube voltages( P > 0.05), but there were and statistically significant with different noise indices ( F=10.57, 17.77, 9.33, P < 0.001). Different tube voltages had no statistical significance for CTDI vol and DLP ( P > 0.05), while different noise indices had statistical significance for CTDI vol and DLP ( F=59.87, 60.92, P < 0.001). The detection rates of nodules were moderately or weakly correlated with noise indices, CTDI vol and DLP ( r=0.43, 0.56, -0.58, -0.78, P<0.05), but no correlation with tube voltage ( P>0.05). Conclusions:Scanning protocol has an impact on AI detection efficiency of pulmonary nodules. Reasonable scanning parameters should be selected according to different image quality requirements in clinical practice.

Objective:To investigate the effects of organ dose modulation (ODM) on image quality and radiation dose to lens during sinus CT scanning.Methods:The GE Revolution EVO CT was used to scan the anthropomorphic head with ODM turned off as the control group and ODM turned on as the observation group. With different parameter combinations of tube voltage (140, 120, 100 kV), noise index (N17, N18), pitch (0.531, 0.969 at 20 cm collimation width, 0.516, 0.984 at 40 mm collination width), 24 series of images were acquired respectively. The tube current (mA) valuesat the anterior (A), left (L), posterior (P) and right (R) positions, volume CT dose index (CTDI vol) and dose length product (DLP) were recorded. Average CT values (AV), standard deviation (SD), signal-to-noise ratio (SNR), contrast to noise ratio (CNR) and image quality factor (FOM) of ROI were calculated. Double blind method was used to evaluate the edge sharpness, soft tissue level, noise and artifact on a subjective scale of 3 points. Results:For the combinations of different scanning parameters, the radiation dose of the observation group was lower than that of the control group. The tube current attheposition A for the observation group was lower than that of the control group, and the difference was statistically significant ( t=2.28, P<0.05). The differences oftube currentsatposotions of L, P and R, CTDI vol and DLP values in twogroupswere not statistically significant ( P>0.05). There were no significant differences in SD, SNR, CNR and FOM between the two groups of images ( P>0.05). There were no significant differences in the subjective scores of edge sharpness, soft tissue gradation, noise and artifacts between the two groups ( P>0.05). Conclusions:ODM technique can effectively reduce the radiation dose of eye lens without decompromising the image quality, which could meet the requirements of diagnosis, and accord with the principle of radiological protection optimization.

Objective:To investigate the effect of different additional filters on the image quality and radiation dose in abdominaldigital radiography (DR).Methods:Retrospective analysis was performed on 10 cases of abdominal DR from December 2020 to January 2021 in Fuxing Hospital, and the average mAs was calculated. Using automatic exposure control (AEC) technology, a polymethyl methacrylate (PMMA) slab of the corresponding thickness (18 cm) at the same output of above mAs was confirmed and used as the attenuator to simulate the abdomen. The phantom of CDRAD 2.0 and 17 slices of 10 mm thick PMMA plates (total thickness 18 cm) were placed on the bed. The additional filters were selected as no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mmAl respectively. The AEC levels were selected at -2, -1, 0, 1, and 2 respectively. The images were collected and analyzed by using CDRAD 2.0 software to obtain the image quality factor (IQF inv). The incident air kinetic energy on the surface of the PPMA was measured for each exposure, and PCXMC software was used to estimate the organ dose and effective dose, and a comparative analysis was made. Results:The skin incident doses at no additional filter, 2 mmAl, 0.1 mmCu+ 1 mmAl, 0.1 mmCu+ 2 mm Al were (0.546 1±0.200 8), (0.376 2±0.133 8 ), (0.285 3±0.100 1) and (0.289 9±0.099 2) mGy, respectively. The estimated effective doses were (79.63±29.24)×10 -3, (71.05±25.56)×10 -3, (63.58±22.18)×10 -3 and (67.64±23.11)×10 -3 mSv, respectively. The gonadal doses were (0.058 1±0.020 8), (0.050 0±0.018 0), (0.044 8±0.015 6) and (0.047 7±0.016 3) mGy.The IQF inv values were 4.70±0.61, 4.80±0.84, 4.60±0.55, 4.60±0.60, respectively. There were linear correlations between the effective dose and the skin incident dose under different additional filtration, and the effective doses increased with the increase of the incident doses. The dose was lowest at the addition filtration of 0.1 mmCu+ 1 mmAl. There was no significant difference in the IQF inv between groups( P>0.05). Conclusions:The optimal additional filtration for abdominal DR was 0.1 mmCu+ 1 mmAl with the image quality meeting the requirements of clinical diagnosis, the radiation dose reduced reasonably, and the objective of the optimization of radiographic parameters achieved.

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated proteins (Cas) system is a hotspot of gene editing and gene expression research, in which CRISPR/Cas13 system provides a new direction for RNA interference and editing. In this study, we designed and synthesized the corresponding gRNAs of CRISPR/Cas13a and CRISPR/Cas13b systems in non-homologous end joining (NHEJ) pathway, such as Ku70 and Lig4, and then detected the expression of ku70 and lig4 in HEK293T cells. The CRISPR/Cas13a system could efficiently knockdown the mRNA expression of ku70 and lig4 more than 50%, and CRISPR/Cas13b system also suppressed ku70 and lig4 about 92% and 76%, respectively. Also, CRISPR/Cas13a, b systems could down-regulate Ku70 and Lig4 proteins level to 68% and 53%, respectively. The study demonstrates that the CRISPR/Cas13 system could effectively knockdown the expression of RNA and protein in HEK293T cells, providing a new strategy for gene function and regulation research.
CRISPR-Cas Systems ; DNA Ligase ATP ; genetics ; Gene Expression Regulation ; genetics ; Gene Knockdown Techniques ; HEK293 Cells ; Humans ; Ku Autoantigen ; genetics

With the traffic accident, sudden disaster and safety accidents occur year after year, the injured patients often complicated with multiple injuries, how to maximize the treatment of the injury to improve the survival rate, is an important problem faced by orthopedic surgeons.In recent years, damage control orthopaedics (DCO) technology has been gradually developed, DCO aims to control the patients' primary injury, to prevent further deterioration of the disease, compared with the traditional treatment, it can effectively reduce the second strike and complications, is conducive to the recovery of patients.In this paper, the development of DCO concept, the theoretical basis of DCO, the adaptation of DCO, the implementation steps of DCO and the best time, the application of DCO in the treatment of severe multiple injuries and the prospect of DCO application are reviewed.

Objective To investigate the albumin(ALB) and total protein(TP) levels among adult Tibetans with different clinical types of hyperlipidemia in Ganzi County and its correlation with serum liver function in-dexes .Methods The serum was collected from 661 volunteers in Ganzi County .The blood lipid metabolism indexes ,liver function indexes and serum protein levels were measured .The hyperlipidemia was performed the clinical typing according to the Guide on Prevention and Treatment of Chinese Adult Dyslipidemia in 2007 . The statistical analysis was conducted by using the one-way ANOVA variance ,Pearson correlation and multi-ple linear regression analytical methods .Results The hypercholesterolemia group ,hypertriglyceridemia group ,mixed hyperlipidemia group and low high-density lipoprotein hyperlipidemia group had 212 ,140 ,85 ,43 cases respectively ,while 181 cases were in the non-hyperlipidemia .The TP level in the patients with mixed hy-perlipidemia was significantly higher than that in the patients with non-hyperlipidemia ,the difference was sta-tistically significant (P<0 .05) .The liver function indexes ALT ,AST and γ-GGT levels in the hypercholes-terolemia group ,hypertriglyceridemia group and mixed hyperlipidemia group were significantly higher than those in the non-hyperlipidemia group ,the difference was statistically significant (P<0 .05) .The serum pro-tein level was strongly correlated with ALT and AST in the hypertriglyceridemia group and mixed hyperlipi-demia group ,the difference was statistically significant (P<0 .05) .TP serving as the dependent variable and ALB ,ALT and AST as independent variables ,the regression analysis showed TP=25 .149+1 .066(ALB)-0 .158(ALT)+0 .268(AST) in hypercholesterolemia ,TP= 28 .211+ 1 .011(ALB) -0 .067(ALT)+ 0 .176 (AST) in mixed hyperlipidemia and TP=37 .86+0 .79(ALB)-0 .079(ALT)+0 .162(AST) in non-hyperlipi-demia .Conclusion TC and TG can induce the damage of liver function in hyperlipidemia ,ALT and AST are the important indicators affecting serum protein level in the patients with hyperlipidemia .In Tibetan adult population of the Ganzi county ,only the TP level change is noticeably among the patients with mixed hyperlip-idemia ,which may be related with strong compensatory ability of liver function in Tibetan population .

Objective:To establish the practice training platform of medical imaging technology conforming to the demand of society and the characteristics of vocational education, and improve the training conditions and promote the quality of higher vocational talent cultivation.Methods: To carry out investigation and expert interviews in various grade hospital; analyze vocation standard and skill training grade; plan and design the layout and function position of hardware for this training platform; and then take practice research for application of this platform.Results: The training platform of medical imaging technology has been established which includes 14 digital training rooms. Every teaching function, such as radiology registration, detection, image processing, diagnostic reporting, report printing and storage capability, could achieve and correspond to a clinical task.Conclusion:This study effectively improves medical imaging technology vocational practice conditions, and has a great significance to improve teaching quality of education and ensure quality of talents cultivation.

Objective: To design a new type of maintenance learning machine of ventilator for teaching and experiment combined with electronic technology course of higher vocational education. Methods: ACM804 ventilator was chosen as prototype machine and the electronic technology course of higher vocational education was chosen as theory basis. The designs of internal circuit and gas circuit of prototype machine were improved, besides, some test points and failure points were designed for teaching in classroom. Results: This machine not only could realize all functions of prototype machine, but also could carry forward test teaching and contribute students to maintain common failure in accordance with course content. Conclusion: Through the design of teaching experiment and using of learning machine, the new machine has achieved better teaching effect for students to grasp machine theory and operate actual circuit.

Objective:To analyze the teaching status of medical imaging equipment and the requirement of medical imaging equipment for graduates majored in medical imaging technique, and then make great progress in the teaching reform of medical imaging equipment.Methods:Discussed with students, conduct investigations and surveys on kinds of hospital in Beijing, and analyzed the survey data.Results: With the analysis of survey, the teaching reform scheme was proposed in the course.Conclusion: To establish the foundation for the teaching reform of medical imaging equipment.