Objective To investigate the interseed dose attenuation for multiple 125I seeds.Methods Monte Carlo simulation was done by Geant 4 to investigate the dose distribution of single seed and multiple seeds.The results were compared with the dose calculation method from TG43-U1 and examined by experiments.Results The difference of single seed dose distribution between Monte Carlo method and line source model was ± 3％.The difference between Monte Carlo method and experiment result was ± 5％.The interseed dose attenuation of multiple seeds at the interesting points was 3.8％ to 13.2％ and the average interseed dose attenuation was 7.2％.The difference of experiment result and Monte Carlo result was less than 6％.Conclusions The interseed attenuation is about 7％ and the maximum value may be larger than 13％ for multiple seeds.The interseed dose attenuation may be larger in tissue.So it is not accurate to calculate the dose distribution by using TG43-U1.

AIM :To investigate the association of primary open-glaucoma (POAG), intraocular pressure (IOP) and systemic blood pressure in a rural population aged 50 years old or above in Shaanxi Province, China.METHODS: In the population-based, cross-sectional study, 1 775 (83.53%) residents, aged 50 years old or above, from 3 counties of Shaanxi Province, China, undertook an interview with a standard questionnaire and a detailed eye examination, including logarithm of the minimum angle of resolution visual acuity, slit-lamp biomicroscopy, applanation tonometry and dilated fundus examination. Two blood pressure reading in the sitting position were taken. Gonioscopy was performed if a narrower peripheral anterior chamber (less than one fourth of the corneal thickness) was indicated. Automated visual field testing was performed by participants assessed to have suspicion of glaucomatous disc damage or if IOP was 22mmHg or higher.RESULTS: IOP significantly correlated with systemic blood pressure, and both IOP and systolic blood pressure increased significantly with increasing age. No association between POAG and hypertension was found. The frequency of POAG increased significantly with lower diastolic perfusion pressure.CONCLUSION: Data in our study are accordance with those reported in other population-based studies, and confirm that lower diastolic perfusion pressure is a significant risk factor for primary open angle glaucoma.

AIM: To assess the prevalence and risk factors for age-related macular degeneration (AMD) in a rural population in Shaanxi Province of China.METHODS: A total of 2 835 (81.00%) people aged 40 years old or more, from Fuping county, Jingbian county and Yang county of Shaanxi Province, China, underwent a comprehensive interview and a relative eye examination. The present of AMD was classified into neovascular AMD (NV) and pure geographic atrophy (GA) by using direct ophthalmoscopy for fundus examination according to International Classification System.RESULTS: The prevalence (95% CI) of AMD was 3.00% (2.42, 3.71) in this population, of which NV accounted for 1.45% (1.05, 1.98) and 1.55% (1.14, 2.10)for GA. The prevalence of AMD increased significantly with increasing age (P ＜0.001). AMD was present in 0.47% of participants aged 40 to 49 years, rising to 11.90% of participants older than 80 years, of which the corresponding data increased from 0.28% to 4.76% for NV and from 0.19% to 7.14% for GA. No significant difference was found in the prevalence of NA and GA between genders in this population. With multiple logistic analyses, apart from advancing age, only smoking was found to have a strong association with any type of AMD.CONCLUSION: The prevalence of AMD in the rural population of Shaanxi Province of China is lower than that reported from other population-based studies in different provinces of China, less than that reported in whites, more than that reported in blacks. Except increasing age, smoking is also a significant well-known risk factor for AMD.

· AIM: To assess the prevalence and related risk factors for primary angle-closure glaucoma in a rural population for 40 years of age or older in Shaanxi Province.· METHODS: By using a stratified, cluster-based, random sampling technique, 8 500 persons of all ages were selected randomly, including 3 500 those aged 40 years or more, from the North, the South and the Middle of Shaanxi Province in Western China from July to December in 2003. All participants had an interview with a standard questionnaire and those questions related to glaucoma of previous diagnosis and treatment, family history and outbreak history. Then a detailed and relative eye examination was performed, including logarithm of the minimum angle of resolution visual acuity, external eye examination with slit-lamp biomicroscopy and fundus examination. The intraocular pressure was measured with Perkins applanation tonometry to those persons aged 50 years old or more and those with suspected increased IOP. A further examination was performed to those persons with suspicious glaucoma, including repeated tonometric examination, gonioscopy, dark room test, automated visual field testing, et al.·RESULTS: 6 815 of the eligible 8 500 persons of all ages were interviewed and examined from July to December in 2003, a response rate of 80.18%, including 2835 of the eligible 3 500 persons of 40 years old or more with a response rate of 81.00%. According to Van Herick method, the percentage of shallow peripheral anterior chamber was 13.6%, of which 10.4% was in grade 2, 3.0% in grade 1, and 0.2% in grade 0. In this rural population for 40 years of age or older 31 participants were found to have primary angle-closure glaucoma, with the prevalence of 1.09%. With multiple logistic analyses, the prevalence increased significantly with age (P=0.008), whereas no significant difference (Pgender=0.180, Peducation=0.199) was found in the rate with gender and education, although women and illiteracy seemed to be at increased risk of the disease (OR: 1.77, 95%CI,0.77-4.10; OR: 1.71, 95%CT, 0.76-3.87). Of 31 participants, 21 persons (67.74%) had not been previously diagnosed and treated. Of 10 participants previously diagnosed, 6 (60%) had been received peripheral iridectomy; nevertheless, no any other treatments were performed. 48.39% participants suffered from visual impairment in various degrees, of which the percentage of blindness in either eye accounted for 29.03%. Of those with primary angle-closure glaucoma, 22 persons (70.97%) were classified as having chronic from of the disease.· CONCLUSION: In this rural population in Shaanxi Province of China, the rate of occludable angles is 13.6%, more common than that reported previously in other Chinese populations. The prevalence of primary angle-closure glaucoma is close to that from other Asian populations, increasing with age. A majority of glaucoma was undiagnosed and untreated previously.

· AIM: To assess the prevalence and related risk factors of primary open angle glaucoma (POAG) in a rural population in Shaanxi Province.· METHODS: By using a stratified, duster-based, random sampling technique, 8 500 persons of all ages were selected randomly, from the North, the South and the Middle of Shaanxi Province from July to December in 2003. All participants had an interview with a standard questionnaire and those questions related to glaucoma of previous diagnosis and treatment, family history and outbreak history. Then a detailed and relative eye examination was performed, including logarithm of the minimum angle of resolution visual acuity, external eye examination with slit-lamp biomicroscopy and fundus examination. The intraocular pressure was measured with Perkins applanation tonometry to those persons aged 50years old or more and those with suspected increased IOP. A further examination was performed to those persons with suspicious glaucoma, including repeated tonometric examination, gonioscopy, dark room test, automated visual field testing, et al.· RESULTS: 6 815 of the eligible 8 500 persons of all ages were interviewed and examined from July to December in 2003, a response rate of 80.18%. 9 participants were found to have POAG, with the prevalence of 0.13%, age ranging from 38 to 80 years (mean year:62.0). In those aged 30 years old or more, the prevalence of the disease was 0.23%, 0.28% and 0.39% for those more than 40 and 50 years old, respectively. The rate of suspicious POAG was 0.18% (12 cases) with age ranging from 35 to 77 years (mean year: 54.7). With multiple logistic analyses, the prevalence increased significantly with age (P=0.023). Other than increasing age, myopia was also a strong risk factor for POAG. Of 9participants with POAG, only 2 cases (22.22%) had been previously diagnosed. No one with POAG was received any treatment previously. 66.67% (6 cases) participants with POAG suffered from visual impairment in various degrees secondary to POAG. The percentage of blindness in either eye was 33.33%.· CONCLUSION: The prevalence of POAG is close to that from other Chinese populations, increasing with age. A majority of glaucoma was undiagnosed and untreated previously.

Objective:This study aimed to detect the special methylation profile in peripheral blood for hepatocellular carcinoma (HCC). Methods:The methylation status of 12 tumor suppressor genes (TSGs) in the plasma of 55 HCCs and 54 chronic liver diseases (CLDs) was tested by methylation-specific PCR (MSP). Results:In HCC, the methylation frequencies were 78.18%in APC, 63.64%in cyclin D2, 58.18% in TFPI2, 49.09% in DKK3, 49.09% in GSTP1, 47.27% in p16, 40.00% in Sigma 14-3-3, 18.18% in SFRP2, 16.36% in ppENK, 9.09% in DKK2, 7.27% in NPTX2, and 5.45% in LHX1. In CLD, the methylation frequencies were 27.78% in APC, 22.22%in cyclin D2, 7.41%in TFPI2, 3.70%in DKK3, 16.67%in GSTP1, 37.04%in p16, 37.04%in Sigma 14-3-3, 11.11%in SFRP2, 20.37%in ppENK, 7.41%in DKK2, 7.41%in NPTX2, and 9.26%in LHX1. The methylation frequencies of APC, cyclin D2, TFPI2, DKK3, and GSTP1 were higher in HCC than in CLD (P<0.01). The methylation index (MI) of the five-gene methylation profile was statistically higher in HCC (median, 0.6;IQR, 0.4-0.8) than CLD (median, 0.2;IQR, 0-0.2) (P<0.01). In HCC, MI was statistically related to the patient's age. Older patients with HCC had a higher MI. No significant correlation was observed between MI and other clinicopathological data. Moreover, MI was not related to the disease free survival and the overall survival in HCC. Conclusion:This five-gene methylation profile may be a promising biomarker for the assistant diagnosis of HCC.

Objective To evaluate diagnostic endoscopic submucosal dissection(D-ESD) for gastric intraepithelial neoplasia(GIN).Methods From January 2012 to May 2016,64 patients with biopsy-proven LGIN who accepted magnifying endoscopy combined with digitalchromoendoscopy(ME-DCE) and D-ESD in Gastrointestinal Endoscopy Center of Nanfang Hospital affiliated to Southern Medical University were retrospectively analyzed in this study.The consistency of ME-DCE prediction with D-ESD pathologic outcome was analyzed by using Kappa test.According to D-ESD pathologic outcome,the two groups were analyzed with independent t-test,chi-square test,or Fisher's exact probability test.Results Sixty-four patients with biopsyproven LGIN were enrolled;25 and 39 patients were predicted by ME-DCE as LGIN and HGIN/differentiated adenocarcinoma respectively;27 and 37 patients were diagnosed as LGIN and HGIN/differentiated adenocarcinoma by D-ESD respectively.ME-DCE prediction was well consistent with D-ESD pathologic outcome(k =0.676).According to pathologic outcome of D-ESD,no significant difference was observed in lesion size,biopsy amount,D-ESD sample size,complete resection rate,operation time period,complications,length of hospital stay,or in-hospital cost(P＞0.05).Conclusion ME-DCE can be proposed when the endoscopic biopsy indicates LGIN.And D-ESD should be performed for definitive diagnosis when the MEDCE indicates HGIN/differentiated adenocarcinoma.

Objective To evaluate the use of double balloon endoscopy(DBE) in diagnosis of ulcerative lesions in small intestine.Methods Data of patients diagnosed as small intestinal ulcer under DBE during September 2003 and December 2007 at Nanfang Hospital were analyzed retrospectively.Results Ulcer in small intestine was detected by DBE in a total of 62 patients,including 48 males and 14 females,aging from 10 to 71 years old( mean 43.9 yr).The main clinical manifestations consisted of small intestinal hemorrhage(38/62,61.3%),abdominal pain(16/62,25.8%),abdominal distention(5/62,8.1%),loss of weight(2/62,3.2%),and diarrhea(1/62,1.6%).The ulcers were diagnosed endoscopically as Crohn's disease(CD) in 53 cases(85.5%),drug induced lesions in 4(6.5%),nonspecific chronic inflammation in 2(3.2%),lymphoma in 2(3.2%) and tuberculosis in 1(1.6%).They were all microscopically diagnosed as chronic inflammation.Of the 62 patients,32(51.6%) underwent surgery.In 30 cases of CD diagnosed by DBE,22 were confirmed by post-surgery pathology(malignant cells were found in 3),while in the other 8 cases,4 were diagnosed as lymphoma,3 as Behcet's disease and 1 as tuberculosis.Meanwhile,the 1 case of tuberculosis and 1 lymphoma diagnosed by DBE were confirmed as CD after operation.The overall accurate diagnosis rate of small intestinal ulcerative lesions by DBE was 68.8%(22/32).Conclusion DBE is valuable in diagnosis of ulcerative lesions in small intestine,but surgery should be included into consideration to confirm the diagnosis when necessary.

Objective To evaluate the effectiveness of single balloon enteroscopy (SBE) in diagno-sing of suspected lesions in small intestine. Methods Data of 23 patients with suspected small intestinal disease, who underwent SBE (Olympus) between February 2009 and August 2009, were retrospectively studied. A total of 34 procedures were performed in 23 patients. The indications for the examination were suspected obscure gastrointestinal bleeding (n = 9), abdominal pain (n = 7), suspected intestinal tumor re-vealed by capsule endoscopy (n = 4), and Crohn disease (n = 3). Results The average preparation time of SBE was less than 5 minutes. The mean procedure time was 61±25 minutes and 67±28 minutes for the oral and anal routes, respectively. Examination of whole length of small intestine was achieved in 6 patients. The diagnostic rate of small-intestinal lesions was 60. 9%, and no severe complications including perforation occurred. Conclusion SBE is safe and easy to prepare and perform, which can be a useful diagnostic and therapeutic tool for suspected small bowel disease.

ObjectiveTo investigate whether the eight- year program students retain the skills from the endoscopy simulator gastroscopy training.Methods4 trainees accepted virtual reality simulator gastroscopy training and performed a standardized VR gastroscopy scenario at the end of training,and after a median 12 months without practice ( retention ).The intensified training was done by trainees based on the differences between the training end and the retention for a median 12 months and the number of intensified training times was found.ResultsThe significant differences existed in the overinsufflation and opeirational force and time.The score at the training end was better than after retention.Through the average 5.5 times intensified trainings the original levels could be reached.ConclusionThrough Endoscopy Simulator the key skills could be retained well and through a litde training the original levels could also be reached.