Objective To compare the dosimetric and radiobiological differences of helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in craniospinal irradiation. Methods The CT images of 15 patients who received craniospinal irradiation in our hospital were selected. The target volumes and organs at risk (OARs) were contoured, and HT and VMAT plans were designed. The dosimetric parameters of the two plans were compared. A Matlab program based on equivalent uniform dose was developed to calculate the normal tissue complication probability (NTCP). The NTCP values of the two plans were compared. Results The homogeneity index of the target volume in the HT group was better than that in the VMAT group, with values of 0.06 ± 0.01 and 0.08 ± 0.24, respectively, and the difference was statistically significant (P=0.03). However, there was no significant difference in the conformity index of the target volume (P>0.05). There were significant differences in key indicators (D_mean, V₅, D_max) of the lungs, liver, lens, and eyeballs between the two groups (P<0.05). Regarding OARs, the NTCP values of the lens, optic chiasm, lungs, and liver in the HT and VMAT groups were as follows: 0.04 ± 0.03 vs. 0.1 ± 0.06 in the left lens, 0.04 ± 0.06 vs. 0.1 ± 0.07 in the right lens, 0.16 (0.14-0.17) vs. 0.21 (0.18-0.24) in the optic chiasm, 3.89 × 10⁻⁴ (2.45 × 10⁻⁴-7.3 × 10⁻⁴) vs. 8.95 × 10⁻⁴ (5.19 × 10⁻⁴-1.75 × 10⁻³) in the lungs, and 3.45 × 10⁻⁸ (6.0 × 10⁻⁹-1.036 × 10⁻⁷) vs. 9.54 × 10⁻⁸ (1.70 × 10⁻⁸-2.056 × 10⁻⁷) in the liver; the HT group was superior to the VMAT group, and all differences were statistically significant (P<0.05). The NTCP values of the heart in the two groups were 1.35 × 10⁻⁸ (6.34 × 10⁻⁹-2.06 × 10⁻⁹) vs. 5.06 × 10⁻⁹ (2.29 × 10⁻⁹-7.9 × 10⁻⁹), significantly lower in the VMAT group than in the HT group (P<0.05). Conclusion HT has high homogeneity and consistency. The two plans have their own advantages in OAR protection. For OARs with no significant differences in physical dosimetry, NTCP results can be used as a reference. Therefore, comparing the dosimetric parameters and OAR NTCP of HT and VMAT plans can help select the optimal clinical treatment strategy.

OBJECTIVE To establish a method for simultaneous determination of venetoclax， busulfan and voriconazole in plasma of patients with acute myeloid leukemia （AML）， and apply it clinically. METHODS Plasma samples were subjected to protein precipitation using acetonitrile and subsequently analyzed by liquid chromatography-tandem mass spectrometry （LC-MS/MS） using venetoclax-D 8 ， busulfan-D 8 and posaconazole as internal standards. The separation was performed on a Phenomenex Kinetex ® C 18 column with a mobile phase composed of 0.1% formic acid solution （2 mmol/L ammonium acetate）-0.1% formic acid in acetonitrile （gradient elution） at a flow rate of 0.8 mL/min. The column temperature was set at 40 ℃， the sample size was 5 μL， and the total run time was 3.10 min. An electrospray ionization source was employed， and positive ion scanning was conducted using multiple reaction monitoring mode. The ion pairs used for quantitative analysis included m/z 868.4→636.3 （venetoclax）， m/z 264.1→151.1 （busulfan）， and m/z 350.1→224.0 （voriconazole）. The above LC-MS/MS method was adopted to determine plasma concentrations of venetoclax and voriconazole in 10 AML patients， as well as plasma concentration of busulfan in 5 patients undergoing conditioning treatment for allogeneic hematopoietic stem cell transplantation. RESULTS The linear ranges of venetoclax， busulfan and voriconazole were 50-10 000， 15-3 000 and 50-10 000 ng/mL， respectively （ R 2 ≥0.999 0）， with lower limits of quantification of 50， 15 and 50 ng/mL， respectively. The RSDs of intra-day and inter-day precision tests for all three analytes were all less than 10%， with accuracy （relative errors） ranging from －10.00% to 12.96%. The average extraction recovery ranged from 92.54% to 100.95%， and the average matrix effect was 89.98%-101.49%. Dilution reliability covered all dilution factors used in the test samples， and the absolute values of relative errors in stability tests were all≤16.25%. The plasma concentrations of venetoclax， busulfan and voriconazole in enrolled patients were 496.20-4 250.45， 233.48-2 002.28 and 475.51-5 710.18 ng/mL， respectively. CONCLUSIONS The LC-MS/MS method established in this study is rapid， sensitive and easy to operate， and can be used for the therapeutic drug monitoring of venetoclax， busulfan and voriconazole.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective:To investigate the independent clinical factors of live birth rate of the first frozen-thawed embryo transfer (FET) cycle after transcervical resection of adhesion (TCRA).Methods:A retrospective case-control study was conducted to analyze the clinical data of patients with intrauterine adhesion (IUA) who received FET in Reproductive Center of Reproductive and Genetic Hospital of CITIC-XIANGYA from January 2019 to June 2022 ( n=6 154). According to the severity of intrauterine adhesions in patients, they were classified into mild adhesions ( n=172), moderate adhesions ( n=5 723), and severe adhesions ( n=259). Based on the FET outcome, the patients were divided into live birth group and non-live birth group. The risk factors and protective factors of live birth were analyzed by multivariate logistic regression. Results:1) No independent factor of live birth was found in the mild IUA group. 2) In the moderate IUA group, the protective factors of live birth included secondary infertility ( OR=1.39, 95% CI: 1.07-1.80, P=0.015), hysteroscopic polypectomy ( OR=1.38, 95% CI: 1.05-1.83, P=0.023), No. of high-quality embryos transferred (one embryo: OR=1.58, 95% CI: 1.37-1.82, P<0.001; two embryos: OR=2.55, 95% CI: 1.80-3.64, P<0.001), two embryos transferred ( OR=1.77, 95% CI: 1.48-2.12, P<0.001), embryo stage (blastocyst transferred, OR=4.93, 95% CI: 3.68-6.63, P<0.001; blastocyst+cleavage transferred OR=1.90, 95% CI: 1.11-3.21, P=0.021), preimplantation genetic testing embryo ( OR=1.42, 95% CI: 1.19-1.69, P<0.001), endometrial thickness before transplantation ( OR=1.11, 95% CI: 1.07-1.15, P<0.001). Risk factors of live birth included female age ( OR=0.94, 95% CI: 0.92-0.96, P<0.001), infertility due to male factor ( OR=0.83, 95% CI: 0.71-0.96, P=0.011), combined repeated implantation failure ( OR=0.60, 95% CI: 0.42-0.87, P=0.007), combined unicornuate uterus/uterus didelphys ( OR=0.25, 95% CI: 0.06-0.79, P=0.033), American Fertility Society score ( OR=0.94, 95% CI: 0.89-0.98, P=0.010), No. of TCRA ( OR=0.83, 95% CI: 0.77-0.90, P<0.001), gonadotropin-releasing hormone agonists down-regulation combined with artificial cycle ( OR=0.56, 95% CI: 0.45-0.69, P<0.001), artificial cycle ( OR=0.62, 95% CI: 0.51-0.76, P<0.001). 3) In the severe IUA group, the risk factor of live birth was artificial cycle ( OR=0.25, 95% CI: 0.07-0.80, P=0.027). Conclusion:The clinical factors that affect the live birth outcome of the first FET cycle after TCRA have different results in patients with different degrees of adhesion. In patients with moderate adhesions, there are 17 clinical indicators that affect the live birth rate. In patients with severe adhesions, the artificial cycle is an independent factor affecting the live birth rate.

Creutzfeldt-Jakob disease(CJD)is a rapidly progressive and fatal neurodegenerative disorder caused by prions,with certain infectivity and iatrogenic transmission risks.With the rapid progress and application of new dia-gnostic biomarkers and detection methods,as well as the construction and improvement of surveillance and reporting systems,the detection of CJD in patients domestically and internationally has shown an increasing trend year by year.Due to its long incubation period and heterogeneity of early symptoms,early identification and diagnosis of the disease is difficult,increasing the risk of transmission within medical institutions.Currently,there is a lack of con-sensus on the infection prevention and control of CJD.In order to timely identify and diagnose CJD as well as effec-tively block its transmission in medical institutions,this consensus summarizes 15 clinical concerns and formulates 24 specific recommendations based on the latest domestic and international research findings and clinical evidence,as well as combines with clinical practice,aiming to standardize healthcare-associated infection prevention and control measures for CJD and reduce its transmission risk in medical institutions.

Creutzfeldt-Jakob disease(CJD)is a rapidly progressive and fatal neurodegenerative disorder caused by prions,with certain infectivity and iatrogenic transmission risks.With the rapid progress and application of new dia-gnostic biomarkers and detection methods,as well as the construction and improvement of surveillance and reporting systems,the detection of CJD in patients domestically and internationally has shown an increasing trend year by year.Due to its long incubation period and heterogeneity of early symptoms,early identification and diagnosis of the disease is difficult,increasing the risk of transmission within medical institutions.Currently,there is a lack of con-sensus on the infection prevention and control of CJD.In order to timely identify and diagnose CJD as well as effec-tively block its transmission in medical institutions,this consensus summarizes 15 clinical concerns and formulates 24 specific recommendations based on the latest domestic and international research findings and clinical evidence,as well as combines with clinical practice,aiming to standardize healthcare-associated infection prevention and control measures for CJD and reduce its transmission risk in medical institutions.

Objective To propose a method for mass spectrometry imaging(MSI)super-resolution reconstruction based on a spatially multi-level and self-supervised deep learning network(SMSDL-Net),aiming to improve the resolution of mass spectrometry images.Methods SMSDL-Net firstly registered histological and mass spectrometry images using a nonlinear transformation.Then a multi-branch Vision Transformer(ViT)was utilized to extract hierarchical features of high-resolution histological images in a self-supervised manner.These features were subsequently combined with the paired low-resolution mass spectrometry data to construct a regression network,which could realize the prediction of high-resolution mass spectrometry information.To validate the performance of the proposed method,the results by the method were compared with those of the traditional bicubic interpolation(BI)methods based on interpolation processing and the deepFERE method based on convolution neural network(CNN)for super-resolution reconstruction of magnesium elemental image of metal mass spectrometry of human liver cancer samples,and the method was also applied to a mouse renal adenocarcinoma metabolite mass spectrometry imaging dataset.Results Compared with the traditional BI methods and the deepFERE multimodal method,the method proposed demonstrated the lowest root mean square error(RMSE=0.015),the highest structural similarity index measure(SSIM=0.84)and the highest R-squared value(R2=0.853)in reconstructing mass spectrometry images.The effectiveness of the method and its potential for precise tissue-specific distinction were validated using the mouse renal adenocarcinoma metabolite MSI dataset.Conclusion Compared with traditional single-modal and pixel-wise regression deep learning methods,the method proposed enhances the quality of high-resolution mass spectrometry image reconstruction and can serve as a novel method for super-resolution reconstruction in the field of mass spectrometry imaging.[Chinese Medical Equipment Journal,2025,46(4):1-8]

In recent years,FLASH radiotherapy(FLASH-RT),as a cutting-edge radiotherapy technology,has developed rapidly in basic research and clinical trials.FLASH-RT can deliver ultra-high dose rate(average dose rate≥40 Gy/s,instantaneous dose rate≥100 Gy/s)irradia-tion in a very short time(usually≤500 ms).Under the premise of maintaining equivalent tumor control rates,the normal tissue injury is less than that of conventional irradiation at the same dose,that is known as the FLASH effect.FLASH-RT has unique advantages and is currently the frontier field of radiation oncology.The research and development of FLASH-RT have progressed rapidly in China,this paper elucidated the new challenges and opportunities of FLASH-RT in China.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objectives:We evaluated the clinical significance of unipolar electrogram and bipolar electrogram in guiding radiofrequency ablation for outflow tract ventricular premature contractions(PVC).Methods:Data were collected from 78 patients who underwent successful radiofrequency ablation of PVC.Pre-procedure electrocardiogram showed a LBBB morphology on inferior leads.In the included patients,the right-side ablation was performed at first,and if the ablation failed,the left-side ablation was then performed.According to the location of the successful ablation target,they were divided into unilateral ablation successful group and bilateral ablation successful group.The differences in the earliest bipolar local activation to QRS(LATBi),unipolar-dV/dTmax to QRS(LATUni),and local activation time were compared between the two groups.Furthermore,the electrogram characteristics predicting bilateral ablation were explored.Results:Patients were divided into unilateral ablation group(n=57)and bilateral ablation group(n=21)according to the ablation site.There were statistically significant differences in LATBi(25[21,30]ms vs.14[10,24]ms),LATUni(7[0,17]ms vs.-23[-41,-11]ms),and ΔLATBi-Uni(15[11,25]ms vs.44[25,56]ms)between the unilateral ablation group and the bilateral ablation group(all P<0.05).Multivariate regression analysis suggested that LATBi,LATUni,and ΔLATBi-Uni were independent predictors of the need for bilateral ablation.There was no significant difference between left and right LATBi,LATUni and ΔLATBi-Uni in the bilateral ablation group.LATUni≤-1 was the most accurate parameter for predicting the need for bilateral ablation(AUC=0.941;specificity 80.7%;sensitivity 100%).Conclusions:LATUni≤-1ms is a useful indicator for predicting the need for bilateral PVC ablation in this patient cohort.