Objective To calculate the mean absorbed doses at celluar and subcellular levels for uniformly and non-uniformly distributed Auger electron emitters. Methods The energy deposited in cell or nucleus by Auger electrons was analytically calculated using the polynomial representation of energy loss.S-values were subsequently computed for several target-source combinations.The absorbed dose and dose distribution were calculated for spherically symmetric radionuclide distributions depending linearly and exponentially on the radial position.The dose profile as a function of the source radial coordinate was also evaluated for typical cell sizes.The contributions of photon radiation to absorbed dose in cells were ignored. Results The mean absorbed dose and dose distribution depend largely on the size of target cells,the radiation spectrum and intracellular localization and distribution of radionuclides.The contribution of intranuclear radionuclides to mean absorbed dose was larger than that of extranuclear ones. Conclusion Auger electrons can produce high local energy deposition in cells because of their very low energies and extremely short ranges.Our dose calculation method is simple.The results are reliable and can be used in many fields.

Objective To investigate three-dimensional dose distribution for 103Pd radioactive stent.Methods The surface dose,the axial dose and radial dose in surface for 103pd stent (3 mm × 13 mm) were estimated by experimental simulating method, analytic function and MCNP4b code. Three-dimensional dose distribution was calculated by MCNP4b code. Results The surface dose of 103pd stent was 0. 109 and 0. 106 Gy estimated by experimental simulating method and MCNP4b code,between which the difference was less than 3%. The axial dose calculated by analytic function and MCNP4b code was well consistent,and so was the radial dose estimated by the three methods. Dose rate table were estimated by MCNP4b code. Conclnsions Dose distribution for 103 Pd stent estimated by the three methods is relatively accurate. Three-dimensional dose table estimated by MCNP4b may be used to calculate dose for 103Pd stent in animal experiment and clinical application.

Objective To perform thermoluminescent measurements of radial dose function and anisotropy function of a newly designed 192Ir microSelectron-HDR source, and establish evaluation methods for HDR dosimetry.Methods A polystyrene phantom with sylindrical holes in different measure positions was designed to accommodate thermo luminescent dosimeter (TLD) rods and radiation source.TLD rods with similar sensitivity were placed on a semicircle around the source center which had been precisely localized by either radiographic means or dose measurement.Dose-rates were measured at θ = 90° and r = 1-14 cm to calculate radial dose function (gL (r)), while measured along polar angles θ = 0° -165°(interval 15°) at radial distances r = 1 cm, 3 cm and 5 cm to calculate anisotropy function (F(r,θ)).All data were compared with those calculated by Monte Carlo (MC) method.The t-test was used for the statistics.Results The values of gL (r) were 1.007 -0.681 by calculation and 1.007 -0.598 by measurement with r = 1 - 14 cm(t = 0.00 - 2.89, all P > 0.05).The values of F (r,θ) were 0.631 - 1,0.660 - 1 and 0.696 - 1 by calculation, while 0.701 - 1, 0.668 - 1 and 0.629 - 1 by measurement at 1 cm, 3 cm and 5 cm with θ=0° -165°(t=0.40 -1.63, 0.02 -2.10, 0.08 -2.03, all P>0.05).Conclusions The results of radial dose function and anisotropy function measured by TLD measurement are in consistent with those calculated by MC calculations, which can be applied in treatment planning system as original input.

Objective To investigate the effect of endovascular treatment of intracranial ruptured vertebral artery dissecting aneurysms via bilateral vertebral artery approach. Methods The symptoms and imaging results of 5 patients with ruptured vertebral artery dissecting aneurysms were analyzed retrospectively. They were all treated with coil embolization via bilateral vertebral artery approach. The two ends of dissection aneurysms were packed densely,the middle segments were packed loosely,and the arteries were isolated from the blood circulation. Results Of the 5 patients after treated,the clinical symptoms were improved rapidly in 4 patients no abnormal limbs activity and mental disorders. After treatment,the modified Rankin scale (mRS)was 0 in four cases after six-month follow-up. One patient turned clear consciousness after 4 weeks, and their mRS was 3 at 6-month follow-up. Before treatment,DSA showed vertebral artery dilation and stenosis. The mean length of involvement in vertebral arteries was 9. 3 ± 1. 5 mm;after treatment,the dissecting aneurysms of 5 patients did not develop completely,no further bleeding occurred,and no new infarcts were observed. No recurrence of the aneurysms and parent artery recanalization were found at the follow-up after 6 months. Conclusion The occlusion of ruptured vertebral artery dissecting aneurysms via bilateral vertebral artery approach is technically feasible. It may be an effective treatment to prevent rebleeding.

Objective To investigate the imaging features of the calvarial cavernous hemangioma and the surgical efficacy to improve diagnosis and treatment of the calvarial cavernous hemangioma.Methods The clinical information,imaging materials and surgical efficacy from ten cases of calvarial cavernous hemangioma confirmed by pathology and the related literature was reviewed.Results The lesion was located in frontal bone in eight cases,in parietal bone in one case and in occipital bone in one case.The lesions were round-shape hypodensity with clear margin in X-ray.The lesions were hyperdensity or slightly hyperdensity on CT scan,and were osteolytic lesions with a characteristic honeycomb or starburst pattern on bone window.The MRI features were complicated and variable.The lesions were heterogenous and unevenly enhanced signal intensity.Nine patients underwent radical resections and reconstructed immediately by titanium mesh.The patient with tumor in occipital bone underwent radical resection only.Macroscopically,the pathologic bone was a huge purple-red blush mass protruding from the skull surface.Histological examination revealed the diploe with large,thin-walled,dilated blood-filled spaces lined by flattened endothelial cells without evidence of malignancy.No recurrence was noted in any case during a follow-up period from 3 to 24 months.All the patients survived well without recurrence.Conclusions The imaging features of calvarial cavernous hemangioma have a high value in the diagnosis and may provide guidance for the treatment.The radical resection and immediate reconstruction treatment for calvarial cavernous hemangioma is satisfied.

Objective:To evaluate the possible mediation effect of smoking and healthy diet score on the association between educational level and the risk of lung cancer incidence.Methods:After excluding individuals with missing educational levels and cancer information at baseline, 446?772 participants in the UK Biobank (UKB) prospective cohort study were included. Cox regression models were used to investigate the associations of educational level and smoking and healthy diet score with the incidence of lung cancer. Mediating effect analysis was conducted to analyze the mediating effect of smoking and healthy diet score on the correlation between educational level and lung cancer.Results:During a median follow-up of 7.13 years, 1?994 new- onset lung cancer cases were observed. Per 1 standard deviation (5 years) increase in educational level was associated with a 12% lower risk of lung cancer ( HR=0.88, 95% CI: 0.84-0.92). The corresponding level 1-5 in the International Standard Classification for Education (ISCED) were mapped to UKB self‐report highest qualification to estimate the educational level. A higher rank means a higher educational level. Compared with level ISCED-1, the HR(95% CI) of level ISCED-2, ISCED-3, ISCED-4 and ISCED-5 were respectively 0.83 (0.72-0.94), 0.67 (0.53-0.85), 0.76 (0.65-0.89) and 0.72 (0.64-0.80) for lung cancer. Education years were negatively correlated with smoking, with β coefficients (95% CI) being -0.079 (-0.081- -0.077), but positively correlated with healthy diet score ( β=0.042, 95% CI: 0.039-0.045). Analysis of mediating effect indicated that the association of educational level with lung cancer risk was mediated by smoking and healthy diet score, the proportions of mediating effect were 38.952% (95% CI: 31.802%-51.659%) and 1.784% (95% CI: 0.405%-3.713%), respectively. Conclusion:Smoking and healthy diet score might mediate the effect of educational level on the incidence of lung cancer, indicating that improving the level of education can reduce the risk of lung cancer by changing lifestyles such as smoking and diet.

Although genome-wide association studies have identified more than eighty genetic variants associated with non-small cell lung cancer (NSCLC) risk, biological mechanisms of these variants remain largely unknown. By integrating a large-scale genotype data of 15 581 lung adenocarcinoma (AD) cases, 8350 squamous cell carcinoma (SqCC) cases, and 27 355 controls, as well as multiple transcriptome and epigenomic databases, we conducted histology-specific meta-analyses and functional annotations of both reported and novel susceptibility variants. We identified 3064 credible risk variants for NSCLC, which were overrepresented in enhancer-like and promoter-like histone modification peaks as well as DNase I hypersensitive sites. Transcription factor enrichment analysis revealed that USF1 was AD-specific while CREB1 was SqCC-specific. Functional annotation and gene-based analysis implicated 894 target genes, including 274 specifics for AD and 123 for SqCC, which were overrepresented in somatic driver genes (ER = 1.95, P = 0.005). Pathway enrichment analysis and Gene-Set Enrichment Analysis revealed that AD genes were primarily involved in immune-related pathways, while SqCC genes were homologous recombination deficiency related. Our results illustrate the molecular basis of both well-studied and new susceptibility loci of NSCLC, providing not only novel insights into the genetic heterogeneity between AD and SqCC but also a set of plausible gene targets for post-GWAS functional experiments.
Adenocarcinoma of Lung/genetics* ; Carcinoma, Non-Small-Cell Lung/genetics* ; Carcinoma, Squamous Cell/genetics* ; Genetic Heterogeneity ; Genetic Predisposition to Disease ; Genome-Wide Association Study ; Humans ; Lung Neoplasms/genetics* ; Polymorphism, Single Nucleotide