ObjectiveTo study of the impact on dose distribution by electron width of energy spectrum and angular distribution using Monte Carlo simulation.MethodsThe simulated electron energy spectrum and angular distributions was as the input parameters and percentage depth dose (PDD) and offaxis curves were simulated by a modified PENELOPE code package. Results PDD and off-axis dose distribution curves are almost the same and are not sensitive to energy spectrum width and angular distribution with the exception of energy spectrum width of 2.5 MeV with obviously different curves.ConclusionsIn the situation of clinical treatment,spectrum and angular distributions can be ignored when their width are not very large.It is helpful to save about 9％ time by using monoenergy beams in treatment planning system development.

ObjectiveTo assess the impact of intense pulsed light (IPL) on the dermatopathological manifestation in a Bama miniature pig model of steroid-induced dermatitis.MethodsFive female Bama miniature pigs aged two months were selected.The white skin areas with white hair at both sides of the neck served as the target area.Halometasone(0.05％) cream was applied to the right target area twice daily for 60 days to establish a model of steroid-induced dermatitis.Then,3 pigs were randomly selected and irradiated with IPL of 25 J/cm2 at the model area with an interval of 3 weeks for 9 weeks,the remaining 2 pigs receiving no treatment served as the natural recovery group.Finally,skin tissues were obtained from the left and right target areas and subjected to haematoxylin and eosin staining for the observation of histopathological changes.ResultsA significant increase was observed in the layer number of keratinocytes and thickness of dermal collagen fiber in the IPL-treated pigs compared with the pigs in natural recovery group (6.27 ± 1.26 vs.2.98 ±0.92,t =3.27,P＜ 0.01; 1.88 ± 0.19 mm vs.0.84 ± 0.15 mm,t =4.25,P＜ 0.01).Moreover,IPL irradiation resulted in the regression of telangiectasis in the dermis.ConclusionIPL may increase skin thickness,relieve flushing and improve skin elasticity efficiently.

[Abstract ] Objective To compare the accuracy between regular computed tomography colonography (CTC)and dual-energy CTC in lesion detection.Methods Twenty-eight patients with clinical suspicious space occupying lesions of the colon were selected.All patients were underwent dual-energy mode contrast-enhanced CT scan and the data were reconstructed with colonography and dual-energy iodine maps methods.The diameter,enhanced computed tomography (CT)value and iodine value were measured.The results of colonoscopy and pathology were taken as gold standard.The sensitivity, specificity,accuracy,positive predictive value and negative predictive value of regular CTC and dual-energy CTC were compared.Variance analysis was performed for measurement data comparison among groups and chi-square test was used for count data analysis.Results Among 28 patients,colorectal lesions were detected in 24 cases by regular CTC,of which four cases were false-positive and one case was false-negative confirmed by colonoscopy and pathology.Colorectal lesions were detected in 20 cases by dual-energy CTC,of which no false-positive and one case was false negative confirmed by colonoscopy and pathology.The contrast enhanced CT value of polyps,adenoma,adenocarcinoma and stool was (38.54± 6.82),(49.16±7.31 ),(52.61 ±5 .93 )and (34.00±1 .41 )Hu,respectively.The enhanced value of adenoma and adenocarcinoma was significantly higher than that of polyps and stool,the differences were statistically significant among groups (F = 10.760,P = 0.001 ).There was no significant difference between polyps and stool (t=1 .44,P =0.188).The sensitivity of regular CTC and dual-energy CTC in lesion detection was 95 .6% (95 %cofidence interval(CI ):77.9%-99.2%)and 95 .6% (95 %CI :77.9%-99.2%),respectively.The specificity was 42.8% (95 %CI :15 .4%-93.5 %)and 100.0% (95 %CI :47.9%-100.0%).Conclusion Compared with traditional CTC,dual-energy CTC would distinguish lesions from stool,help differentiate between benign and malignant tumors and further increase the accuracy of CTC diagnosis.

Objective To conduct the 7th investigation by Chinese Society of Radiation Oncology,Chinese Medical Association,and to further investigate the current situation of radiotherapy in mainland China,reasonably allocate personnel and equipment resources,and promote the development of radiotherapy in China.Methods From October 8,2015 to December 2015,the office for investigation of radiotherapy information was established,the list and contact information of radiotherapy units were provided by each province,and a special data submission system was used for a complete,rapid,and efficient investigation through the Internet.Results As of January 20,2016,there were 1 413 radiotherapy units in the mainland China with 52,496 employees in total,among which there were 15 839 radiotherapy physicians (4824 with senior professional titles),8 452 technical therapists (260 with senior professional titles),3 292 physicists (562 with senior professional titles),and 938 maintenance engineers (120 with senior professional titles).In the aspect of radiotherapy equipment,there were 1930 linear accelerators,96 Co-60 teletherapy units,173 X-knife units,212 γ-knife units,382 Ir-192 brachytherapy units,436 Co-60 brachytherapy units,1 051 X-ray simulators,1 353 CT simulators,642 MRI simulators,978 sets of multileaf collimators,1922 sets of treatment planning systems,and 974 sets of radiotherapy network systems.As for quality control devices,there were 1 792 dosimeters,2 143 ionization chambers,935 two-dimensional array dosimeters,540 threedimensional dosimetric verification systems,596 three-dimensional water tanks,844 anthropomorphic phantoms,and 1 168 water equivalent phantoms.In the aspect of therapeutic situation,there were 102,170 beds (including beds in departments of oncology in general hospitals),76612 episodes per day,and 919339 episodes per year.Conclusions The results of this investigation show significant increases in radiotherapy units,personnel,and equipment in recent years in mainland China.The distribution of radiotherapy units and equipment and the structure of radiotherapy personnel are becoming more reasonable,but there are still some problems.In some regions,current radiotherapy equipment cannot meet the medical needs,and there is a lack of professional technical personnel.

ObjectiveTo compare the calculation precision of the collapsed cone convolution (CCC) algorithm and pencil beam convolution (PBC) algorithm in TPS in heterogeneous tissue.Methods We made two virtual lung phantoms,one is single field phantom,In this case the photon beam incident into the phantom,the other is the two fields phantom and a cubic'tumor' was placed in the centre of the phantom.two opposite photon beams incident into the phantom.We calculated the dose of the'tumor' and the lung with the CCC and PBC algorithm.We compared the results in both case with if obtained from Monte Carlo (MC) method.ResultsIn the single field phantom,the photon beam incident from the high-density tissue to the low-density lung equivalent tissue,compared with the result of MC algorithm PBC algorithm overestimated the lung equivalent tissue dose (t =3.90,P =0.012) and the result of CCC algorithm is close to it ( t =2.25,P =0.087 ).In the two fields phantom,tumor boundary dose calculated by CCC algorithm and the MC algorithm are lower than that of the PBC algorithm (t =2.43,3.18,P =0.038,0.011 ),and the difference increase when the field size decrease, the beam energy increase and the density of the inhomogeneity decrease.ConclusionsWe had better use the CCC algorithm when calculating the dose of the tumor surrounded by low-density tissue or the tumor behind the low-density tissue,such as the lung cancer,esophageal cancer etc.

Objective To investigate the effect of apolipoprotein E gene knock-out(ApoE KO) and high-fat diet on morphology and the expression of mortalin in hippocampal CA_3 neurons of mice, and to explore the impact of these factors on memory and Alzheimer's disease.Methods Ten wild-type and 10 ApoE KO mice were fed with common chow as the control group and the KO group respectively while 10 ApoE KO mice were fed with high fat diet.Twelve weeks later, the weight and the lid of these mice were measured.The brain tissues were observed using HE staining, nissl staining, protargol staining,immunohistochemistry staining and image analysis by computer.Results In the ApoE KO group, weight,total cholesterol, triglyceride, low-density lipoprotein cholesterol were higher than those in the control group,and these changes were more significant in ApoE KO high-fat diet group.The nissl was higher in the ApoE KO group (0.301±0.031) and in ApoE KO high-fat diet group (0.261±0.020) than those in the control group (0.341±0.035, F=18.068, P<0.05).The mortalin in the ApoE KO group (0.322±0.060) and in ApoE KO high-fat diet group (0.391±0.041) were higher than the control group (0.256±0.061, F=15.230, P < 0.05).Conclusions ApoE KO and high-fat diet can reduce nissl, and improve the expression of mortalin.This protein may be involved in the pathogenesis of Alzheimer's disease.

Objective To calculate the effects of thermoplastic mask on X-ray surface dose.Methods The BEAMnrc Monte Carlo Code system, designed especially for computer simulation of radioactive sources, was performed to evaluate the effects of thermoplastic mask on X-ray surface dose.Thermoplastic mask came from our center with a material density of 1.12 g/cm2. The masks without holes,with holes size of 0. 1 cm× 0. 1 cm, and with holes size of 0. 1 cm × 0. 2 cm, and masks with different depth (0.12 cm and 0.24 cm) were evaluated separately. For those with holes, the material width between adjacent holes was 0. 1 cm. Virtual masks with a material density of 1.38 g/cm3 without holes with two different depths were also evaluated. Results Thermoplastic mask affected X-rays surface dose. When using a thermoplastic mask with the depth of 0. 24 cm without holes, the surface dose was 74. 9% and 57.0% for those with the density of 1.38 g/cm3 and 1.12 g/cm3 respectively. When focusing on the masks with the density of 1.12 g/cm3, the surface dose was 41.2% for those with 0.12 cm depth without holes;57.0% for those with 0. 24 cm depth without holes;44. 5% for those with 0. 24 cm depth with holes size of 0.1 cm ×0.2 cm;and 54.1% for those with 0.24 cm depths with holes size of 0.1 cm ×0.1 cm.Conclusions Using thermoplastic mask during the radiation increases patient surface dose. The severity is relative to the hole size and the depth of thermoplastic mask. The surface dose change should be considered in radiation planning to avoid severe skin reaction.

Objective To establish the population pharmacokinetics(PPK)model of Lamotrigine(LTG)in children with epilepsy in China for promoting individualized dosage regimen. Methods The sparse data of LTG serum concentrations from 60 pediatric patients with epilepsy were collected. One hundred and fourteen serum concentration points were divided into LTG+valproic acid (VPA) group(n=56),LTG+enzymatic inducer(E1)group(n=26),LTG+EI+VPA group(n=16)and single LTG group(n=16).The serum drug concentrations were the clinical routinely tested steadv state concentrations.The LTG PPK parameters were calculated using the non-parametric expectation maximization(NPEM) Program of USC*PACK software,and then a PPK model was established. Based on this model,LTG serum concentrations were predicted with Bayesian fitting program of USC*PACK software.Mean prediction error(MPE)and mean squared prediction error(MSPE) were calculated to evaluate the accuracy and precision of the concentration prediction and to valid the PPK model.Results The greatest likelihood was-192.87.Optimum PPK parameters were:Ka=(1.97 1.66)h~(-1);Vs=(1.07±0.89)L/kg;Kel=(0.05±0.05)h~(-1).The linear regression function Y_(OBS)=-0.09+1.05 Y_(PRED)(R~2=0.98,P<0.001),and determination of coefficient was 0.98.MPE was-0.16 g/mL,and MSPE was 0.28(μg/mL)~2.Conclusion A PPK model of LTG in children with epilepsy in China can be successfully established using the USC*PACK software, based on which LTG serum concentrations can be predicted accurately with a Bayesian approach.

Objective To investigate influence on dose distribution due to cavity and inhomogeneous structures using thermoluminescence dosimeters (TLD) and Chengdu phantoms.Methods A cavity 4 cm × 4 cm × 3 cm was made by a head and neck phantom and a lung phantom was cut into slices which were got a CT scanning and setup in a digital simulator.The TLD were pasted on edge and in the center of cavity structure and inhomogeneous structures.Treatment plans of different radiotherapy technologies were made generated and delivered on a linear accelerator.Then the TLD were read and analyzed.Results There were remarkable cavity effects of conventional single field,opposite fields and IMRT plans with 7 fields for head and neck phantom.There is similar effect in lung phantom.The more complexity the radiotherapy technology was the less cavity effect.Conclusions It is necessary to consider using more advanced radiotherapy technology or applying more fields to make treatment plans in order to decrease the cavity effect or similar effect when there are inhomogeneous structures.

Objective To identify clinical predictive factors in intractable childhood epilepsy,to provide some evidence for its early diagnosis.Methods Six hundred and twenty-four children with newly diagnosed epilepsy were retrospectively identified in Xinhua Hospital Affiliated to Shanghai Jiaotong University Medical School(1993-2009).The epileptic children were divided into a drug-responsive epilepsy group (n =584) and an intractable epilepsy group (n =40).Clinical data of patients were retrospectively analyzed,including the gender,age,pathogen,inducement,number of pre-treatment seizures,seizure type,seizure type change,seizure duration,family history,previous history,physical examination,brain CT and initial electroencephalogram(EEG) findings.Single factor analysis and Logistic regression analysis were made in 2 groups.Results Strong univariate associations suggested that some factors could increase the risks of intractable epilepsy:symptomatic or cryptogenic epilepsy,mental retardation,type of infantile spasm,positive neurological examination and large absolute number of pre-treatment seizures,and changes in seizure types in the course of the disease.With multiple Logistic regression,independent predictors of intractability were symptomatic or cryptogenic etiology(OR =3.61),large absolute number of pre-treatment seizures and changes in seizure types in the course of the disease(OR =4.76).Conclusions It's necessary to be wary of intractable epilepsy and to adjust therapy accordingly when seizures were uncontrollable and accompanied by one or more conditions such as symptomatic or cryptogenic epilepsy,large absolute number of pre-treatment seizures,changes in seizure types in the course of the disease.