Transmission X-ray tubes are relatively new devices characterized by portability,suitability for miniaturization,and low requirements for shielding,making them ideal radiation sources for kilovoltage X-ray therapy.However,their application in radiotherapy remains underexplored.An electron target model of a transmission X-ray tube is developed using the Monte Carlo toolkit TOPAS 3.8.1.The study investigates the effect of tungsten target thickness on X-ray output efficiency,finding that a tube voltage of 50 kV and a tungsten thickness of 1.4 μm yields the highest emission efficiency.Based on the energy spectrum at this optimal efficiency,polynomial fitting approach is applied to determine the corresponding aluminum filter thickness for mean energies ranging from 20 keV to 35 keV,achieving a mean fitting error of 0.91%.Next,the study simulates dose deposition in a water phantom for spectra with different mean energies and various source-to-surface distances,and plots percent-depth-dose curves,relative normalized dose-depth curves,and relative normalized dose histograms under each treatment condition.Finally,the simulated results are compared with experimental data from the intraoperative radiotherapy system Intrabeam and the superficial X-ray therapy unit SRT-100,obtaining average relative errors of 3.71%and 4.38%,respectively.These findings provide a theoretical foundation for further optimization of transmission X-ray tubes in kilovoltage radiotherapy.

Transmission X-ray tubes are relatively new devices characterized by portability,suitability for miniaturization,and low requirements for shielding,making them ideal radiation sources for kilovoltage X-ray therapy.However,their application in radiotherapy remains underexplored.An electron target model of a transmission X-ray tube is developed using the Monte Carlo toolkit TOPAS 3.8.1.The study investigates the effect of tungsten target thickness on X-ray output efficiency,finding that a tube voltage of 50 kV and a tungsten thickness of 1.4 μm yields the highest emission efficiency.Based on the energy spectrum at this optimal efficiency,polynomial fitting approach is applied to determine the corresponding aluminum filter thickness for mean energies ranging from 20 keV to 35 keV,achieving a mean fitting error of 0.91%.Next,the study simulates dose deposition in a water phantom for spectra with different mean energies and various source-to-surface distances,and plots percent-depth-dose curves,relative normalized dose-depth curves,and relative normalized dose histograms under each treatment condition.Finally,the simulated results are compared with experimental data from the intraoperative radiotherapy system Intrabeam and the superficial X-ray therapy unit SRT-100,obtaining average relative errors of 3.71%and 4.38%,respectively.These findings provide a theoretical foundation for further optimization of transmission X-ray tubes in kilovoltage radiotherapy.

Objective To develop a rapid and accurate Monte Carlo program(simplified code for dosimetry of carbon ions,SPEEDO)for carbon ion therapy.Methods For electromagnetic process,type Ⅱ condensed history simulation scheme and continuous slowing down approximation were used to simulate energy straggling,range straggling,multiple scattering,and ionization processes.For nuclear interaction,5 types of target nuclei were considered,including hydrogen,carbon,nitrogen,oxygen,and calcium.The produced secondary charged particles followed the same condensed history framework.The study simulated the transport of carbon ions in 4 materials(water,soft tissues,lung,and bone),and the calculated doses were validated against TOPAS(a Monte Carlo simulation software for radiotherapy physics),followed by a comparison with dose measurements in a water phantom from the HIMM-WW(a medical heavy-ion accelerator facility in Wuwei).Results SPEEDO's simulation results showed good consistency with TOPAS.For each material,in the voxel region where the physical dose was greater than 10％of the maximum dose point,the relative maximum dose error of both was less than 2％.At treatment energy of 400 MeV/u,SPEEDO's computation time was significantly less than that of TOPAS(13.8 min vs 105.0 min).SPEEDO's calculation results also showed good agreement with HIMM-WW measurements in terms of lateral dose distribution and integrated dose depth curve.Conclusion SPEEDO program can accurately and rapidly perform Monte Carlo dose calculations for carbon-ion therapy.

Objective To develop a GPU-based Monte Carlo dose calculation module for helical tomotherapy(TOMO),and integrate it into the commercial software ArcherQA to achieve fast and accurate dose verification in clinic.Methods The TOMO treatment head was modeled using TOPAS to obtain phase space files,and a fast weight tuning algorithm was used to simulate particle transport in multi-leaf collimator for improving computational efficiency,and finally,GPU-based Monte Carlo algorithms in ArcherQA were used to simulate particle transport in patients.To verify the model accuracy,the ArcherQA calculated results in water tank were compared with measured data for different open fields.In addition,multiple comparisons among ArcherQA results,TPS results and ArcCHECK results were conducted on 15 clinical cases(5 cases in the head and neck,5 cases in the chest and abdomen,and 5 cases in the whole body).Results In the water tank tests for 40 cm×5.0 cm,40 cm×2.5 cm and 40 cm× 1.0 cm radiation fields,the average global relative errors of the percentage depth dose,transverse dose distribution,and longitudinal dose distribution calculated by ArcherQA with the corresponding measured values were 0.72％,0.66％,and 0.54％,respectively.Over 98％of the voxels had a global relative error of less than 1％.As for 15 clinical cases,in 2％/2 mm criteria,the mean Gamma passing rate was 98.1％between ArcherQA and TPS,99.1％between TPS and ArcCHECK,and 99.4％between ArcherQA and ArcCHECK.The uncertainty of the simulation maintained less than 1％,and the average time taken for calculation based on patient CT vs ArcCHECK phantom was 87 s vs 64 s.Conclusion ArcherQA can be used for independent dose validation for TOMO plans for it can provide fast and accurate dose calculations.

BACKGROUND: Liver biopsy for the diagnosis of non-alcoholic steatohepatitis (NASH) is limited by its inherent invasiveness and possible sampling errors. Some studies have shown that cytokeratin-18 (CK-18) concentrations may be useful in diagnosing NASH, but results across studies have been inconsistent. We aimed to identify the utility of CK-18 M30 concentrations as an alternative to liver biopsy for non-invasive identification of NASH. METHODS: Individual data were collected from 14 registry centers on patients with biopsy-proven non-alcoholic fatty liver disease (NAFLD), and in all patients, circulating CK-18 M30 levels were measured. Individuals with a NAFLD activity score (NAS) ≥5 with a score of ≥1 for each of steatosis, ballooning, and lobular inflammation were diagnosed as having definite NASH; individuals with a NAS ≤2 and no fibrosis were diagnosed as having non-alcoholic fatty liver (NAFL). RESULTS: A total of 2571 participants were screened, and 1008 (153 with NAFL and 855 with NASH) were finally enrolled. Median CK-18 M30 levels were higher in patients with NASH than in those with NAFL (mean difference 177 U/L; standardized mean difference [SMD]: 0.87 [0.69-1.04]). There was an interaction between CK-18 M30 levels and serum alanine aminotransferase, body mass index (BMI), and hypertension ( P  < 0.001, P  = 0.026 and P  = 0.049, respectively). CK-18 M30 levels were positively associated with histological NAS in most centers. The area under the receiver operating characteristics (AUROC) for NASH was 0.750 (95% confidence intervals: 0.714-0.787), and CK-18 M30 at Youden's index maximum was 275.7 U/L. Both sensitivity (55% [52%-59%]) and positive predictive value (59%) were not ideal. CONCLUSION This large multicenter registry study shows that CK-18 M30 measurement in isolation is of limited value for non-invasively diagnosing NASH.
Humans ; Non-alcoholic Fatty Liver Disease/diagnosis* ; Keratin-18 ; Biomarkers ; Biopsy ; Hepatocytes/pathology* ; Apoptosis ; Liver/pathology*

Background/Aims: Chronic hepatitis B (CHB) and fatty liver (FL) often co-exist, but natural history data of this dual condition (CHB-FL) are sparse. Via a systematic review, conventional meta-analysis (MA) and individual patient-level data MA (IPDMA), we compared liver-related outcomes and mortality between CHB-FL and CHB-no FL patients. Methods: We searched 4 databases from inception to December 2021 and pooled study-level estimates using a random- effects model for conventional MA. For IPDMA, we evaluated outcomes after balancing the two study groups with inverse probability treatment weighting (IPTW) on age, sex, cirrhosis, diabetes, ALT, HBeAg, HBV DNA, and antiviral treatment. Results: We screened 2,157 articles and included 19 eligible studies (17,955 patients: 11,908 CHB-no FL; 6,047 CHB-FL) in conventional MA, which found severe heterogeneity (I2=88–95%) and no significant differences in HCC, cirrhosis, mortality, or HBsAg seroclearance incidence (P=0.27–0.93). IPDMA included 13,262 patients: 8,625 CHB-no FL and 4,637 CHB-FL patients who differed in several characteristics. The IPTW cohort included 6,955 CHB-no FL and 3,346 CHB-FL well-matched patients. CHB-FL patients (vs. CHB-no FL) had significantly lower HCC, cirrhosis, mortality and higher HBsAg seroclearance incidence (all p≤0.002), with consistent results in subgroups. CHB-FL diagnosed by liver biopsy had a higher 10-year cumulative HCC incidence than CHB-FL diagnosed with non-invasive methods (63.6% vs. 4.3%, p<0.0001). Conclusions IPDMA data with well-matched CHB patient groups showed that FL (vs. no FL) was associated with significantly lower HCC, cirrhosis, and mortality risk and higher HBsAg seroclearance probability.

Myocardial dysfunction is the most serious complication of sepsis. Sepsis-induced myocardial dysfunction (SMD) is often associated with gastrointestinal dysfunction, but its pathophysiological significance remains unclear. The present study found that patients with SMD had higher plasma gastrin concentrations than those without SMD. In mice, knockdown of the gastrin receptor, cholecystokinin B receptor (Cckbr), aggravated lipopolysaccharide (LPS)-induced cardiac dysfunction and increased inflammation in the heart, whereas the intravenous administration of gastrin ameliorated SMD and cardiac injury. Macrophage infiltration plays a significant role in SMD because depletion of macrophages by the intravenous injection of clodronate liposomes, 48 h prior to LPS administration, alleviated LPS-induced cardiac injury in Cckbr-deficient mice. The intravenous injection of bone marrow macrophages (BMMs) overexpressing Cckbr reduced LPS-induced myocardial dysfunction. Furthermore, gastrin treatment inhibited toll-like receptor 4 (TLR4) expression through the peroxisome proliferator-activated receptor α (PPAR-α) signaling pathway in BMMs. Thus, our findings provide insights into the mechanism of the protective role of gastrin/CCKBR in SMD, which could be used to develop new treatment modalities for SMD.

Chronic alcohol consumption causes liver steatosis, cell death, and inflammation. Melatonin (MLT) is reported to alleviate alcoholic liver disease (ALD)-induced injury. However, its direct regulating targets in hepatocytes are not fully understood. In the current study, a cell-based screening model and a chronic ethanol-fed mice ALD model were used to test the protective mechanisms of MLT. MLT ameliorated ethanol-induced hepatocyte injury in both cell and animal models (optimal doses of 10 μmol/L and 5 mg/kg, respectively), including lowered liver steatosis, cell death, and inflammation. RNA-seq analysis and loss-of-function studies in AML-12 cells revealed that telomerase reverse transcriptase (TERT) was a key downstream effector of MLT. Biophysical assay found that epidermal growth factor receptor (EGFR) on the hepatocyte surface was a direct binding and regulating target of MLT. Liver specific knock-down of Tert or Egfr in the ALD mice model impaired MLT-mediated liver protection, partly through the regulation of nuclear brahma-related gene-1 (BRG1). Long-term administration (90 days) of MLT in healthy mice did not cause evident adverse effect. In conclusion, MLT is an efficacious and safe agent for ALD alleviation. Its direct regulating target in hepatocytes is EGFR and downstream BRG1-TERT axis. MLT might be used as a complimentary agent for alcoholics.

LIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28's role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.
Animals ; Cell Differentiation ; Embryo, Mammalian/metabolism* ; Embryonic Development ; Mice ; Pluripotent Stem Cells/metabolism* ; RNA, Messenger/genetics* ; RNA, Ribosomal ; RNA-Binding Proteins/metabolism* ; Transcription Factors/metabolism* ; Zygote/metabolism*

Cutaneous T-cell lymphomas are a relatively rare group of mature T-cell lymphomas mainly manifesting in the skin, and its common subtype is mycosis fungoides. Total skin electron irradiation is one of the important conventional treatment methods, but there are many disadvantages, such as uneven dose distribution, poor position repetition, and long treatment time, which affect the clinical efficacy and patient prognosis. With the emergence and gradual popularization of helical tomotherapy in recent years, more and more medical institutions are gradually expanding their applications in total skin irradiation due to their ability to treat ultra-long targets and achieve dose-sculpted distribution, aiming to further explore its good or bad, and confirm whether it can replace the traditional total skin electron irradiation. In this article, research progress on total skin irradiation using helical tomotherapy was reviewed, the development of treatment technology, clinical efficacy and current concerns and controversies were illustrated.