Objective With the Monte Carlo method to recaleulate the IMRT dose distributions from four TPS to provide a platform for independent comparison and evaluation of the plan quality.These results wiU help make a clinical decision as which TPS will be used for prostate IMRT planning.Methods Eleven prostate cancer cases were planned with the Corvus,Xio,Pinnacle and Eclipse TPS.The plans were recalculated bv Monte Cado using leaf sequences and MUs for individual plans.Dose-volume-histograms and isodose distributions were compared.Other quantities such as Dmin(the minimum dose received by 99% of CTV/PTV),Dmax(the maximum dose received by 1%of CTV/PTV),V110%,V105%,V95%(the volume of CTV/PTV receiving 110%,105%.95% of the prescription dose),the volume of rectum and bladder receiving>65 Gy and>40 Gy,and the volume of femur receiving>50 Gy were evaluated.Total segments and MUs were also compared.Results The Monte Carlo results agreed with the dose distributions from the TPS to within 3%/3 mm.The Xio,Pinnacle and Eclipse plans show less target dose heterogeneity and lower V65 and V40 for the rectum and bladder compared to the Corvus plans.The PTV Dmin is about 2 Gy lower for Xio plans than others while the Corvus plans have slightly lower female head V50(0.03%and 0.58%)than others.The Corvus plans require significantly most segments(187.8)and MUs(1264.7)to deliver and the Pinnacle plans require fewest segments(82.4)and MUs(703.6).Conclusions We have tested an independent Monte Carlo dose catculation system for dose reconstruction and plan evaluation.This system provides a platform for the fair comparison and evaluation of treatment plans to facilitate clinical decision making in selecting a TPS and beam delivery system for particular treatment sites.

Objective To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification.Methods Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria.The plans were copied to water-phantem,0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose.The statistical data of the parameters of beams for the 43 cases were collected,and the relationships among them were analyzed.The statistical data of the dosimetry error were collected,and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results.Results The parameters of beams were correlated among each other.Obvious affiliation existed between the dose accuracy and parameter settings.When the beam segment number of IMRT plan was more than 80,the dose deviation would be greater than 3％ ; however,if the beam segment number was less than 80,the dose deviation was smaller than 3％.When the beam segment number was more than 100,part of the dose deviation of this plan was greater than 4％.On the contrary,if the beam segment number was less than 100,the dose deviation was smaller than 4％ definitely.Conclusions In order to decrease the absolute dose verification error,less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80.

Objective To compare the results of three dose verification solutions of esophageal carcinoma IMRT plans. Methods Seven esophageal carcinoma cases were planned with Pinnacle 8.0 h.The MATRIXX and Delta4 were chosen as the two-dimensional dosimetry and three-dimensional dosimetry.IMRT plans and Delta4 phantom plans were also recalculated by Monte Carlo. Gamma values were evaluated for MATRIXX and Delta4 with 3 mm/3% gamma criteria. For the comparison of Pinnacle, Delta4 and Monte gamma maps, the dose distribution in central plane, dose profiles and dose-volume histograms were used to evaluate the agreement. Results The gamma maps comparison show that with 3 mm/3% gamma criteria an over 98% pass ratio was obtained by MATRIXX measurement. A 94. 4% gamma pass ratio whicl.contains 4 fields gamma pass ratio lower than 90%, was obtained by Delta4 measurement. A 97.6% and 99. 8% gamma pass ratio was obtained between the Delta4 measurement and Monte Carlo simulation with 2 mm/2% and 3 mm/3% gamma criteria. The dose distribution in central plane and dose profiles from Pinnacle calculation were almost in agreement with both the Monte Carlo simulation and Delta4 measurement. The DVH plot have slightly differences between Pinnacle and Delta4 measurement as well as Pinnacle and Monte Carlo simulation, but have excellent agreement between Delta4 measurement and Monte Carlo simulation. Conclusions It was shown that all the three methods can be used very efficiently to verify esophageal carcinoma IMRT delivery, Delta4 and Monte Carlo simulation no data missed. The primary advantage of Delta4 is the fact it can measure true 3D dosimetry while Monte Carlo can simulate in patients CT images but not in phantom.

ObjectiveTo measure the setup errors with infrared marker-based positioning system (IM-BPS) and electronic portal imaging device (EPID) for patients with esophageal carcinoma and lung cancer and investigate the accuracy and practicality of IM-BPS. MethodsFrom January 2007 to January 2008, 40 patients with esophageal carcinoma and 27 patients with lung cancer received three-dimensional conformal radiotherapy or intensity-modulated radiotherapy, setup errors during the treatment were measured with IM-BPS and EPID, and the data of setup errors were compared with paired t-test and agreement with x2-test. ResultsIt takes 10 - 12 mins to complete the validating for each patient by EPID) system, while IMBPS system only needs 2 -5 mins. The mean setup errors along x, y and z-axis for patients with esophageal carcinoma measured by IM-BPS and EPID were 3.49 mm, 3. 19 mm, 3.31 mm and 4. 03 mm, 3.41 mm, 3.43 mm, respectively. For the patients with lung cancer, the setup errors were 4. 23 mm, 3.51 mm, 3. 39mm and 4. 85 mm, 3. 53 mm, 3.74 mm, respectively. The difference of setup errors meanured by the two systems was within 1 mm for 65％ esophageal carcinoma patients ( x2 =51.09, P =0. 000), and 55％ lung cancer patients ( x2 =53. 35, P =0. 000).Conclusions The measurement results of setup errors for patients with esophageal carcinoma and lung cancer show that IM-BPS is mostly better than EPID. Though validating for patients can be measured accurately and be well quality controlled, IM-BPS is used easily because of macroscopic, homely,spare time and real-time monitoring.

ObjectiveTo evaluate correlation factors of cervical lymph nodes metastasis in thoracic esophageal carcinoma.MethodsLocal-regional metastasis of lymph node for 126 cases with esophageal squamous cell cancer after surgery from 2004 to 2009 were reviewed.Risk factors of cervical lymph nodes metastasis were examined by multiple Logistic regression analysis.ResultsIn 126 cases,supraclavicular lymph node metastasis rate was 43.7％ (55/126).By logistic regression,none of the primary site,T stage,N stage,histological grade,lymph node metastasis rate,lymph node metastasis degree and number of lymph nodes metastatic field was not the high risk of cervical lymph nodes metastasis.In addition,multivariate analysis found that lymph node metastasis in mediastinum region 1 was high risk factor for lymph node metastasis of region 1 ( x2 =12.14,9.27,P =0.000,0.002),lymph node metastasis in region Ⅲ and region 2 were high risk factors for lymph node metastasis of region Ⅱa ( x2 =14.56,8.27,8.02,3.93,P =0.000,0.004,0.005,0.047 ).ConclusionMediastinal para-recurrent nerve lymph node metastasis is a significant predictor for cervical lymph nodes metastasis.

Objective To investigate the application of the Monte Carlo dose calculation of output factors for electron beams in radiotherapy.Methods The code EGS4/MCTP was used to simulate the head of a medical linear accelerator (Varian 23EX) to calculate the output factors for 6 MeV,9 MeV and 18 MeV electron beams.The source-to-surface distance used was 100 cm.The field sizes ranged from 2 cm × 2 cm to 25 cm × 25 cm.The calculated output factors agreed with the corresponding measured factors which were measured by the IBA Phantom system to within 2％.Then,the output factors of direct articles and indirect articles which were under different energy and various cone-insert combinations were calculated by the code EGS4/MCTP.Results The calculated output factors agreement with the measurements is found to be mostly under the 1％ level.The variation of output factors depends on the characteristics of the beams and the modifications that the various cone-insert combinations introduce to these characteristics.Conclusions Monte Carlo dose calculations for electron beams in homogeneous water phantoms have been demonstrated to be accurate under the 1％ level in comparison with measurements.The output factors were influenced by energy and cone-insert combinations in complex ways.

Objective To explore the relationship and the clinical significance of homeobox gene B1 (HOXB1 )and microRNA-31 75 (miR-31 75)expressions in human glioma.Methods The expression levels of HOXB1 and miR-31 75 in 60 glioma tissues and 1 5 normal brain tissues were analyzed by real-time fluores-cent quantitative PCR (qRT-PCR).Spearman rank correlation analysis was performed to explore the relation-ship between HOXB1 and miR-31 75 in human glioma tissues.The relationship between HOXB1 (or miR-31 75)and clinical pathological characteristics of glioma patients was analyzed.The correlation of HOXB1 (or miR-31 75)and survival rate was calculated by Kaplan-Meier.And COX regression models were used to assess the prognostic factors.Results Compared with normal brain tissues,the expression of HOXB1 was significant-ly decreased in glioma tissues (1 .498 ±0.323 vs.0.946 ±0.588,t =-5.680,P =0.000);and the expre-ssion of miR-31 75 was obviously increased in glioma tissues (1 .008 ±0.355 vs.2.076 ±0.841 ,t =4.274, P =0.000),and HOXB1 expression was negatively correlated with miR-31 75 expression in glioma tissues (r =-0.601 ,P =0.000).HOXB1 expression was related with histologic grade (χ2 =4.848,P =0.028), and miR-31 75 expression was related with histologic grade (χ2 =5.640,P =0.01 8)and Karnofsky score (χ2 =4.785,P =0.029).The results of Kaplan-Meier revealed that there were significant differences in median survival time between HOXB1 (or miR-31 75)high-expression group and HOXB1 (or miR-31 75)low-expression group [HOXB1 :(21 .0 ±4.0)months vs.(7.0 ±0.8)months;χ2 =7.495,P =0.006;miR-31 75:(6.0 ±0.6)months vs.(1 6.0 ±5.8)months;χ2 =9.591 ,P =0.002].COX regression models showed that tumor degree (RR =6.556,95% CI:1 .1 96-35.952,P =0.002),HOXB1 (RR =0.01 8, 95%CI:0.001 -0.31 2,P =0.006)and miR-31 75 (RR =2.098,95%CI:1 .663-7.51 3,P =0.037)were independent prognostic factors for prognosis.Conclusion The HOXB1 expression may be negatively correlated with miR-31 75 in human glioma tissues,and the expression levels of HOXB1 and miR-31 75 are associated with the glioma malignant degree,survival time and prognosis of glioma patients.

An untargeted urinary metabonomics method based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry ( UPLC-Q-TOF-MS ) has been established to investigate the mechanism of Schisandra chinensis in treating diabetes and its complications. The urinary biomarkers related to the therapeutic effects of Schisandra chinensis on the diabetes rats were analyzed. In urine, 28 kinds of endogenous metabolites were identified as potential biomarkers, including 13 endogenous metabolites in positive ion mode, 15 endogenous metabolites in negative ion mode, and hippuric acid detected both in positive and negative ion modes. The results revealed that Schisandra chinensis mainly affected the pathways of pentose and glucuronate interconversions, riboflavin metabolism, pantothenate and CoA biosynthesis, arginine and proline metabolism, intestinal bacteria metabolism, ascorbate and aldarate metabolism and tryptophan metabolism in diabetic rats. Combined with biological analysis of these pathways, the therapeutic mechanism of Schisandra chinensis on diabetes and its complications was verified. Based on the biological function of each pathway, the effect of Schisandra chinensis on diabetic nephropathy is stronger. Moreover, it also has the effects of protecting liver, decreasing fat and antioxidant activity.

Objective To construct the uniform electron density couch model (model A ED =0.25) and two components non uniform electron density couch model (model B FD =0.5and foam core=0.1) in the Monaco treatment planning system for the iBEAM(R) evo Extension 415,and to compare which model can better quantify the treatment couch influence on radiation dose.Methods Phantom was positioned in the center of the couch,the attenuation of the couch was evaluated with 6 MV for a field size of 10 cm× 10 cm.Dose measurements of couch attenuation were performed at gantry angles from 180.0° to 122.8°,using a 0.125cc semiflex ionization chamber (PTW),isocentrically placed in the center of a homogeneous cylindrical phantom.Each experimental setup was first measured on the linear accelerator and then reproduced in the TPS.By adjusting the relative-to water electron density (ED) values of the couch,the measured attenuation was replicated.The model accuracies of the model A and model B were evaluated by comparing the measured and calculated results at the minimum computational grid (2 mm) and maximum computing grid (5 mm),respectively.Results The maximum measured and calculated percentage deviation for the central phantom position was 4.01％.The couch model was included in the TPS with a uniform ED of 0.25 or a 2 component model with a fiber ED=0.5 and foam core ED=0.1.For model A and B under 2 and 5 mm voxel grid size,the mean absorbed dose with couch was reduced to 0.61％,0.84％,0.71％ and 0.92％from 2.8％ without couch.Conclusions Model A has a good agreement between measured and calculated dose distributions for all different voxel grid sizes and gantry angles.It can accurately describes the dose perturbations due to the presence of the couch and should therefore be used during treatment planning.

Objective Comparing the dosimetric characteristics of volumetric modulated arc therapy (VMAT) and constant dose rate intensity modulated arc therapy (IMAT) in esophagus cancer to evaluate the performance of the two different arc therapy delivery techniques.Methods 22 cases of esophageal cancer patients were selected for the planning comparison study.All plans were done for IMAT and VMAT treatment plans on Oncentra 4.1 treatment planning system,prescription dose of 2 Gy in total 30 fractions.Planning objectives for PTV were at least 95％ reached the prescription dose and V110 no more than 10％.The maximum dose of spinalcord below 45 Gy and double lung dose V20 ≤ 28％,V30 ≤ 18％ were constrained.Plans were evaluated based on the ability to meet the dose volume histogram.The dose homogeneity index (HI),radiation conformity index (CI),radiation delivery time,monitor units and γ pass rate were also compared.SPSS 19.0 software paired ttest analysis was carried out on the two sets of data.Results The results showed that the IMAT plans in terms of the PTV's CI (t =3.35,P=0.003),D2(t =-2.27,P=0.034) lung's V30(t =-2.46,P=0.023) were better than that of VMAT group.But the VMAT plans spinal's V40 (t =2.37,P =0.027),lung's V5 (t =2.43,P =0.024) were superior to that of IMAT plans.There were no significant differences between IMAT and VMAT plans in the average dose of PTV,CTV,GTV,heart,spinal cord,double lung and the γpass rate.Conclusion IMAT presents a slight improvement in the OAR sparing in high dose with shorter treatment time when compared to VMAT.While in terms of delivered MU and tissue of low dose irradiated area is higher than that of in VMAT.These two treatment methods all can meet the clinical demand,which should be selected according to the actual situation of the patient.