Objective To compare and analyze DMLC(Sliding Window,SW)and SMLC(Step and Shoot,SS)for delivering IMRT.Methods 5 patients with nasopharyngeal carcinoma were treated with radical intensity modulated radiation therapy using Varian 23EX and Helios tool on a Varian Eclipse system.Different modalities to deliver IMRT were considered for Sliding Window(SW) and Step and Shoot(SS) techniques using a different number of intensity levels(e.g.5,10 and 20).The total beam-on-time,total delivery time and a number of dose-volume parameters regarding PTV and OARs were considered.Results Comparing with the DVH,it was found that SW was the best of the four modalities in the dose distribution of PTV,but SS was better when considering the protection of OARs.The total beam-on-time(MUs) requirement for SS was 9～23% less than SW,but the total delivery time(in minutes)was about twice as long.Conclusion With the number of intensity level of 10 or more,no differences between SS and SW can be appreciated in the dose distribution of PTV and OARs sparing.Referring to the quality assurance,only leaf position needed to be checked in SS,whereas both leaf position and leaf speed need to be checked in SW,so it is proposed to use SS10 for delivering IMRT.

Defensin is a kind of antimicrobiol and cytotoxic peptides which have been found in a large range of living organisms. The mammal defensins have the most wide range antimicrobiol spectrum. The distribution, structure, gene expression regulation of mammal defensins in China and abroad were summarized. Its application on medicine and plant resistant gene engineering were prospected.

Objective To investigate the gross tumor volume (GTV) changes in nonoperatively treated lung cancer patients during radiotherapy by off-line analysis using kilovoltage cone-beam computed tomography (KVCBCT).Methods Eighteen nonoperatively treated lung cancer patients were divided into group A (n =13) to receive conventional radiotherapy (1.8-2.2 Gy/fraction) and group B (n =5) to receive accelerated radiotherapy (5-8 Gy/fraction).Group A was further divided into subgroup A1 (n =10) and subgroup A2 (n =3) according to GTV changes.Each patient in group A underwent KVCBCT scan before treatment once a week,and each patient in group B underwent KVCBCT scan before each treatment.KVCBCT and CT images were registered in the treatment planning system to analyze GTV changes.Results Of all patients in group A,77％ showed ＞ 20％ GTV reduction.Subgroup A1 had the maximum GTV reduction in the 4th week of treatment (the 20th treatment) ;Subgroup A1 had a mean reduction of (0.94 ± 9.94)％,with a maximum value of-56.76％.Subgroup A2 showed no correlation between GTV changes and treatment time.Group B had a mean GTV reduction of (-7.41 ± 1.76)％,with a maximum value of -15.91％.Of all patients in group B,71％ showed ≤ 10％ GTV reduction.Small GTV changes were observed in group B.Conclusions There are no regular GTV changes in nonoperatively treated lung cancer patients during radiotherapy.Adaptive radiotherapy is recommended in the cases where GTV is reduced over 20％ in the 20th treatment.

Objective To investigate the reconstruction procedures of digestive tract following total gastrectomy.Methods The clinical data of pylorus ring preserving and jejunum interposition for the reconstruction of digestive tract following total gastrectomy in 17 cases of fundus and/or cardia carcinoma in past 3 years in our hospital were reviewed. Results There was no operative death,and no stomach fistula or constriction occurred in this series.All the 17 patients were discharged with recovery. Half a year after the operation, all the patients can eat about 200-300g each time, and 3-4 times a day. Patients′ subject feeling was good; no retrosternal burning pain occurred after meal; no symptoms of bile reflux or empty disorder happened. Conclusions The reconstruction of digestive tract following total gastrectomy using pylorus ring preservation and jejunum interposition should be effective if strict indications are adopted.

Objective To find out the methods for the reconstruction of digestive tract following subtotal gastrectomy. Methods The clinical data of 17 patients with carcinoma of gastric fundus and cardia carcinoma undergoing transabdominal pylorus preserving subtotal gastrectomy for the reconstruction of digestive tract with interposition of jejunum from March 1999 to July 2002 were analyzed retrospectively. Results No death, no stoma fistula, nor constriction were found after operation. All patients were discharged after recovery. Half a year later, patients could eat food of about 200-300 g at each meal (3 or 4 times a day). No burning pain in the postbreast bone, phenomenon of bile reflux, empty disorder, nor dumping syndrome were found after meal. No anemia was found in all patients, and their body weight restored to the preoperative normal level. Conclusion The pylorus reserving transabdominal subtotal gastrectomy for the reconstruction digestive tract with interposition of jejunum can result in satisfactory surgical outcomes if the indications are strictly controlled.

Objective To explorer the application in detection the position accuracy of the multileaf collimator of Varian accelerator with dynamic therapy log files. Methods A pre-designed MLC format files named PMLC for two Varian accelerators, the dynamic treatment log files were recorded 10 times on a different date, and be converted into the MLC format files named DMLC, compared with the original plan PMLC, so we can analysis two files for each leaf position deviation. In addition, we analysis the repeatability of MLC leaves position accuracy between 10 dynalog files of two accelerators. Results No statistically significant difference between the average position of the 10 times leaf position of the two accelerators,their were 0. 29 -0. 29 and 0. 29 -0. 30(z = -0. 77, P=0. 442). About 40% ,30% ,20% and 10% of the leaf position deviation was at ≤0. 2 mm, 0. 3 mm,0. 5 mm and 0. 4 mm,respectively. the maximum value was 0. 5 mm. More than 86% of the leaf position are completely coincident between 10 dynamic treatment files of two accelerators,The rate of position deviation no more 0. 05 mm was 96. 6% and 97.3%, respectively.And the maximum value was 0. 09 mm. Conclusions Dynamic treatment log file is a splendid tool in testing the actual position of multi-leaf collimator. The multi-leaf collimator of two accelerators be detected are precise and stabilized.

Objective To study the influence of the angle of multileaf collimator leaves on segments (control point for sliding windows) number and monitor units in intensity-modulated radiotherapy (IMRT) plan optimization.Methods 10 cases undergone IMRT with rectangle target volume were choosed,2 plan were designed with step and shot technique and sliding windows technique for running direction of collimator with target long axis vertical and parallel respectively,compared the plans with similar optimization parameters for different angle of the collimator.Results The number of segments and monitor units increased by 52.8％ and 49.6％ more than longitudinal direction of leaf collimator with static IMRT respectively,there appeared significant difference (P =0.000) ; and the number of segments and monitor units increased by 58.2％ and 61.9％ more than longitudinal direction of leaf collimator with dynamic IMRT respectively,there appeared significant difference (P =0.000).Conclusions For the optimization of IMRT based on multileaf collimator,the direction of collimator perpendicular to the target long axis,there could be obviously decrease the number of monitor units,shorten the treatment time,improve the treatment efficiency with similar dose distribution.

Objective To compare the technical success ,complication rates and comfort of the radiologic placement of central venous ports(CVP) via the internal jugular vein ,subclavian vein via subclavian region ,subclavian vein via supraclavicular region un‐der DSA guidance .Methods We retrospectively reviewed 188 CVP patients implanted at hospitals between December 2012 and De‐cember 2013 .The patients were divided into three groups according to the different catheter implantation sites ,internal jugular vein (group A) ,subclavian vein via subclavian region (group B) and subclavian vein via supraclavicular region (group C) .Intraoperative pain score ,technical success rates ,peri‐procedural ,as well as early and late complication rates were recorded based on the image fol‐low‐up and patient medical records .Results The technical success rate was 100 .0% without any lethal complications .The CVP re‐lated infections were occurred in each group with 1 patient ,but there was no statistics significant different(P>0 .05) .Subclavian vein thrombosis were occurred 2(2 .1% ,2/96) in group B ,which was recanalized after thrombolytic therapy ,and 1(1 .7% ,1/60) in group C ,which was completely occluded .The higher rate of catheter migration and kinking of catheter were occurred in group A and group C .The rate was statistically significant difference among the three groups (P<0 .01) .The late complication rates were statistically higher in group A and C compared with group B (P<0 .05) .The punch‐off was just occurred in group B (n=2) .There were no significant differences about catheter fracture ,port rotation and wound dehiscence among the three groups(P>0 .05) .Con‐clusion In DSA radiologic placement of a CVP via the subclavian vein via subclavian region is safe and efficient with more comfort‐able and lower complication rates ,which could be chosen priority .

OBJECTIVETo study the clinicopathological features and prognosis of multifocal gastric cancer.

METHODSClinicopathological data of 30 cases with multifocal gastric cancer from January 2003 to March 2014 in our department were retrospectively analyzed. Random selection of 100 cases of single focal gastric cancer patients admitted in the same period was used as control group. Clinicopathological features and prognosis were compared between two groups.

RESULTSSix(20.0%) multifocal gastric cancer patients had 3 or more focuses with different differentiation degrees at the same time. The age of multifocal gastric cancer patients was younger than that of single focal gastric cancer [(56.8±16.4) year vs. (63.3±10.8) year, P<0.05]. The TNM stage of multifocal gastric cancer was mainly stage I((73.3%, 22/30), and the TNM stage of single focal gastric cancer was mainly stage III((64.0%, 64/100). As compared to single focal gastric cancer group, multifocal gastric cancer group had smaller tumors, lower ratio of nerve invasion and lymphatic vascular invasion(all P<0.01). Five-year survival rate was higher in multifocal gastric cancer group as compared to single focal gastric cancer group(76.0% vs. 48.8%, P<0.05). The prognosis of multifocal gastric cancer patients was associated with tumor size, nerve invasion, vascular invasion, depth of tumor invasion, lymphatic metastasis and TNM staging(all P<0.05), which was similar to single focal gastric cancer patients. Differences of 5-year survival rate under various clinicopathological conditions were not significant between two groups(all P>0.05).

CONCLUSIONMultifocal gastric cancer patients have earlier staging tumor and overall advantage as compared to those with single focal gastric cancer.

Objective:To investigate the role of concurrent chemoradiotherapy in the treatment of limited-stage small cell lung cancer (LS-SCLC) and the impact of the number of chemotherapy cycle during radiotherapy (RT) on clinical prognosis.Methods:Patients with LS-SCLC treated with definitive radiotherapy from May, 2008 to September, 2016 were included in the study. The primary endpoint was overall survival (OS), which was calculated from the start of treatment to the date of death or last follow-up. The effect of the number of concurrent chemotherapy cycle and other clinical factors on clinical efficacy was analyzed. Survival analysis was performed with Kaplan- Meier method, and multivariate analysis was performed with Cox regression model. Results:Three hundred and seventeen patients were eligible for the analysis. Among them, 129 patients received sequential chemoradiotherapy and 188 patients received concurrent chemoradiotherapy. Among patients receiving concurrent chemoradiotherapy, 86 patients received 1 cycle of concurrent chemotherapy and 102 cases of 2 cycles of concurrent chemotherapy. The median follow-up time was 22.47 months. Multivariate survival analysis showed that only clinical stage, timing of RT administration and prophylactic cranial irradiation (PCI) were the independent prognostic factor for OS. The median OS in patients who received 1 cycle and 2 cycles of concurrent chemotherapy during RT were 33.8 months and 30.4 months ( P=0.400). No matter in elder patients or in younger patients, in early RT group or in late RT group and application of PCI or not, the number of concurrent chemotherapy cycle exerted no significant impact on OS. The incidence of grade 3 or above adverse events was 20% in the 1-cycle concurrent chemotherapy group, and 13.7% in the 2-cycle concurrent chemotherapy group. Conclusions:Concurrent chemoradiotherapy is the standard treatment of LS-SCLC. Two cycles of concurrent chemotherapy during RT is not necessarily superior to 1 cycle of concurrent chemotherapy. The optimal number of concurrent chemotherapy cycle during RT need to be studied in a large prospective randomized clinical trial.