Objective To compare and analyze the dosimetric characteristics of the intensity-modulated arc therapy (RapidArc) combined with active breathing coordinator (ABC) in the thoracic esophageal carcinoma radiation therapy. Methods Ten thoracic esophageal carcinoma patients undergoing radiotherapy were selected for this study.The CT simulations were performed under three breath patterns respectively:moderate deep inspiration breath-hold (mDIBH) with ABC aid; Set the trigger threshold to 80％ of the peak of the respiration curve; and free breathing (FB).Based on the corresponding CT image sets,three treatment plans were generated for each patient respectively:Arc-ABC( three small arcs),ArcFB (consisted of two coplanar full arcs) and IMRT-FB plan.The following dosimetric parameters were compared among different plans:D2％,D98％,V95,homogeneity index ( HI),conformal index ( CI ) the percentage of volume receiving dose of over x Gy (Vx),monitor unit (MU),control points and treatment time.Results The planning target volume ( PTV ) of FB was 376 cm3 which decreased to 260 cm3 after using ABC.For mDIBH and FB patients,the total lung volumes were 5964.6 cm3(35％ more than FB) and 3838.8 cm3 respectively; the heart volumes were 524.4 cm3 and 642.7 cm3 respectively. No significant difference was observed among Arc-ABC,IMRT-FB and Arc-FB in terms of D2,D98,V95,CI and HI.For Arc-ABC plans,there were significant decreases of radiation dose in total-lung's V10,V20,V30,V40 and mean lung dose ( F =4.38,5.34,4.07,3.89,4.28,P ＜0.05).Various dose decreases of heart V20,V3,V40,Dmean and spinal cord Dmax were observed,yet no statistically significant difference existed.The MUs and total control points of Arc-ABC plans were significantly lower than other plans ( F =26.86,12.56,P ＜ 0.05 ).Conclusions When thoracic esophageal carcinoma patients were treated with radiotherapy,the combined utilization of RapidArc and ABC can potentially decrease the volume of irradiated lung yet escalate the dose in target.

Objective To evaluate the accumulated doses to normal tissues and organs at risks (OARs) of patients with lung cancer in radiotherapy plans by using the deformable registration method,and make comparison with the empirical calculation method.Methods Ten patients with lung cancer were analyzed retrospectively.3D-CRT or IMRT plans were designed before treatment. CT to simulator was rescanned and the same treatment plan was redesigned during radiotherapy. Based on the deformable registration method,the Mimvista software was used to calculate the accumulated doses to normal tissues and OARs in two CT images respectively.The empirical estimation algorithm was calculated by the linear relationship between the fractions and the total prescribed dose.Results The target coverage of patients had no significant difference in two plans.There were no significant differences in all the dose volume parameters for normal tissues and OARs,except the mean dose to right lung( t =2.98,P ＜ 0.05 ) when the the same plan was conducted in position-setting and reposition CT images.Conclusions The empirical estimation for the accumulated dose could be used to evaluate the dose and volume parameters for normal tissues and OARs in lung cancer by the same plan.

Objective To compare the dosimetric differences of target volume and organ at risk between intensity-modulated arc therapy (IMAT) and simultaneously integrated boost intensity-modulated radiotherapy (SIB-IMRT) in nasopharyngeal carcinoma. Methods IMAT and SIB-IMRT treatment plans of 10 nasopharyngeal carcinoma cases were generated by Varian Eclipse ver8. 6 treatment planning system. The dosimetric parameters of target volume and organ at risk (OAR), the monitor units (MU) and treatment time were compared between IMAT and SIB-IMRT treatment plan. Results The conformal index ( CI ) of PTV, PTV1, PTV2 of IMAT and SIB-IMRT were 0. 71 and 0. 75 ( Z = - 2. 32, P ＜ 0. 05 ), 0. 54 and 0. 59 (Z= -2.56,P＜0.05), 0.71 and 0.78(Z= -2.52,P＜0.05), respectively. the homogenous index (HI) of PTV, PTV1, PTV2 of IMAT and SIB-IMRT were 10.5 and 11.2(Z= -0. 84,P＞0.05),13. 1 and 17. 1(Z= -1.68,P＞0.05) and 14. 1 and 13.3(Z= -1. 01,P＞0.05) respectively;the brain-stem mean does were 3512. 8 cGy ± 406. 2 cGy and 3384. 3 cGy ± 361.3 cGy ( Z= - 1.82, P ＞ 0. 05 ); the brain-stem maximum dose were 5528. 1cGy ± 192. 9 cGy and 5727. 5 cGy ± 356. 3 cGy ( Z = - 1.12, P ＞ 0. 05 ); the maximum dose of spinal-cord were were 4186. 1cGy ± 88.7 cGy and 4390. 2 cGy ± 74. 9 cGy ( Z =-2. 38 ,P ＜ 0. 05 ). There were no significant differences between parotid dose and normal tissue ( P ＞0. 05. ) MU were 606 ± 96 and 1308 ± 213 for IMAT and SIB-IMRT ( Z= - 2. 52, P ＜ 0. 05 ). Conclusions The IMAT plan showed a better conformal index than SIB-IMRT plan, with the same dosimetric parameters of the target volume and OAR. The IMAT plan could reduce normal tissues dose, monitor units and treatment time in the treatment of nasopharyngeal carcinoma.

Objective To compare the dosimetric difference of RapidArc and fixed gantry IMRT for liver carcinoma.Methods The CT data of 10 liver cancer patients were used to design 3 groups of treatment plan:IMRT plan,single arc RapidArc plan(RA1) ,and dual arc RapidArc plan(RA2).The planning target volume (PTV) dosimetric distrubition,the organs at risk (OAR) dose,the normal tissue dose,mornitor units(MU) and treatment time were compared.Results The maximum dose of PTV in RA1 and RA2 plans were lower than that of IMRT(Z = -2.090,-2.666,P ＜ 0.05).RapidArc groups had an improved 90% prescription dose conformity index than IMRT(Z = -2.805,-2.809 ,P ＜ 0.05).For organs at risk,RapidArc group plan had a significantly lower dose in V40 of stomach and small bowel than I MRT plan,but higher in mean dose of left kidney (Z = -1.988,-2.191,P ＜ 0.05).The values of V5,V10 and V15 of healthy tissue in RapidArc plan groups were higher than those in IMRT plan,while the values of V20 ,V25 and V30 of healthy tissue in RapidArc plan groups were lower than those in IMRT plan.The number of computed MU/fraction of Rapid Arc plan was 40% or 46% of IMRT plan and the treatment time was 30% and 40% of IMRT.Conclusion RapidArc showed improvements in conformity index and healthy tissue sparing with uncompromised target coverage.RapidArc could lead to the less MU and shorter delivery time compared to IMRT.

Objective To compare and analyze the characteristics of intensity-modulated arc therapy (IMAT) versus fixed-gantry intensity-modulated radiotherapy (IMRT) in the treatment of cervical esophageal cancer.Methods Ten patients treated in our radiotherapy center were selected for this study.Based on the identical CT and planning target volume (PTV), two IMAT plans were generated with Eclipse ver8.6 planning system.IMAT1 consisting of a single 359.8° rotation, and IMAT2 consisting of two coplanar 359.8° rotations.PTV were prescribed to 60 Gy in 30 fractions.Planning objectives for PTV,corresponding with the IMRT plans, were V98 larger than 97% and V110 no more than 15%.The maximum dose of spinal-cord was constrained below 45 Gy.One-way ANOVA were applied to dose-volume values for PTV and OAR from DVH.Results There were no significant differences between IMRT and IMAT in PTV D98, V98, CI or total-lung V5, V10, V30, V40, V50 and mean lung dose (all P > 0.05).However, the differences were significant in terms of D2, V110 and HI of PTV, V20 of the total-lung (all P<0.05).On the MU,IMRT = 1174.8 MU,IMAT1 =709.7 MU,and IMAT2 =803.8 MU (F =39.25,P =0.000).On the treatment time,IMRT= 14.9 min,IMAT1 = 1.9 min, and IMAT2 =2.66 min (F=45.14,P=0.000).Conclusions IMAT is equal to IMRT in dosimetric evaluation.Due to much less MU and delivery time,IMAT is an ideal technique in treating patients by reducing the uncomfortable influences which could effect the treatment.However, IMAT1 is slightly inferior to IMAT2.

Objective To research the feasibility of using three-dimensional CT (3DCT) associated with active breathing control (ABC) in determination of the individual internal tumor volume (ITV) for hepatocellular carcinoma (HCC) comparing the four-dimensional CT (4DCT).Methods After 4DCT scans of 15 HCC patients who had accepted TACE,completed the 3DCT scans associated with ABC in three ways of breathing:free breathing ( FB),end inspiration hold ( EIH),end expiration hold (EEH).4DCT images were sorted into 10 phases and the maximum intensity projection (MIP) images were constructed.The GTVs were manually contoured on 4DCT and 3DCT images (labeled as GTV0,GTV10.….GTV90,GTVMIP,,GTVFB,GTVEIH and GTVEEH).GTV0…GTV90,GTV0 and GTV50,GTV0,GTV20 and GTV50,GTVEIH and GTVEEH were respectively merged into IGTV1,IGTV2,IGTV3,IGTV4.The volume and geometry displacement of GTVs and IGTVs were compared.Results All patients were compatible with the ABC technique and completed the CT scans in two ways.The motion of diaphragm measured between 4DCT and 3DCT images was not significantly different ( 1.39 cm and 1.39 cm,t =-0.02,P =0.983 ),it was similar to the volume difference among GTV0,GTV20,GTV50,GTVEIH,GTVEEH and GTVFB (56.4,54.6,55.5,55.6,55.2,59.7 cm3,F =0.01,P =1.000 ).The comparison result of volume difference among IGTV1,IGTV2,IGTV3,IGTV4 and GTVMIP (77.9,71.4,73.4,72.3 and 66.3 cm3,F =0.02,P =1.000)were similar to the differences of geometry displacement in x,y and z axial among them (F =0.48,0.04,0.02,P =0.750,0.997,0.999,respectively).Conclusion The application of 3DCT associated with ABC in determination of the individual IGTV for HCC is feasible and safe comparing to 4DCT.

Purpose To investigate the dosimetric differences among RapidArc (RA) plans which were designed on different target volumes in hepatocellular carcinoma (HCC).Methods A total of 10 HCC patients underwent 3D-CT scan under free breathing ( FB),end inspiration hold ( EIH ) associated with active breath coordinator (ABC) and 4D-CT scan.The 4D-CT were sorted into 10 sets of CT images according to respiratory cycle.The gross tumor volume (GTV) was manually contoured on different CT images.The individual internal gross target volume ( IGTV1 ) was obtained from 4D-CT,and the individual margins from GTVFB to IGTV1.IGTV2 were obtained from GTVFB using individual margins.The planned target volumes (PTV-1,PTV-2,PTV-3 and PTV-4 ) were obtained from GTVFB,IGTV1,IGTV2 and GTVEIA applying different margins.The RA plans (RA1,RA2,RA3 and RA4 ) were designed from different PTVs,and for RA1,RA2 and RA3 the simple 358° arc were used,while three 135° arcs were used for RA4.The dosimetric differences were compared.Results The PTV-1 and PTV-3 were larger than PTV-2 and PTV-4; the mean values of PtV-1/PTV-2 and PTV-1/PTV-4 were 2.5 and 1.9,respectively.There were no significant differences in conformal index,homogeneity index,maximum dose,and minimum dose of PTV among 4 RA plans.The irradiation dose of normal liver of RA3 and RA4 were 8.23 Gy and 7.63 Gy respectively,both significantly lower than those of RA1 and RA2 (10.21 Gy,9.62 Gy,x2 =10.68,P ＜0.05 ),and the V30of RA3 and RA4 were 5.24％ and 5.05％ respectively,both significantly lower than those of RA1 and RA2 (7.76％,6.12％,x2 =14.76,P ＜ 0.05 ).There were no significant differences in irradiation doses of stomach and duodenum among different plans.Conclusions Using 4D-CT or ABC technology with RapidArc in HCC can define the target volume accurately and achieve prefect dose distribution sparing more normal liver volume,compared to the traditional margins.4D-CT and ABC play similar roles in sparing normal liver.

ObjectiveTo study the feasibility of RapidArc (RA) associated with active breath coordinator (ABC)for hepatocelluar carcinoma (HCC)radiotherapy comparing of three-dimensional conformal radiotherapy (3DCRT),intensity modulated radiotherapy (IMRT),RA treatment plans in different breath status.Methods12 HCC cases were selected.Three series CT scanning were completed in Free Breathing (FB),End Inspiration Hold (EIH) and End Expiration Hold (EEH) associated with ABC device.3DCRT,IMRT and RA (three 135° arcs) treatment plans were respectively designed on planning target volume (PTV) in different breath status.The dosimetric differences among 3 DCRT,IMRT and RA,among RA plans under different breath status were compared.ResultsThe PTV in FB was larger than in EEHand EIH (160.8 cm3,89.5 cm3,83.1 cm3,F=6.63,P=0.004). The conformity index and homogeneity index of RA plans were better than IMRT and 3DCRT ( 0.92,0.90,0.77,F =72.55,P =0.000 ;0.90,0.89,0.84,F =125.49,P =0.000 ) ;the V20,V30,V40 of normal liver in 3DCRT were higher than IMRT and RA (24％,20％,19％,F=3.56,P =0.032;13％,10％,10％,F=5.74,P =0.004;8％,5％,6％,F =3.72,P =0.027).The normal liver mean dose,V10,V20,V30,V40 of RA plans in FB were higher than in EEH and EIH ( 13.46 Gy,10.25 Gy,9.48 Gy,F =3.627,P =0.038 ;46％,35％,32％,F =2.96,P=0.066;24％,16％,16％,F=3.69,P=0.036;13％,8％,8％,F=4.28,P=0.022;8％,5％,5％,F =2.39,P =0.108 ).The duodenum D5 cm3 of RA in EEH was lower than in FB and EIH (8.78 Gy,19.35 Gy and 11.67 Gy,F =1.56,P =0.224 ).The mean monitor units for 3 DCRT,IMRT,RA was 254.06 MU,626.33 MU and 550.28 MU ( F =147.35,P =0.000 ),while the mean treatment time was 135 s,540 s and 130 s respectively (F =62.83,P =0.000).ConclusionsThe RapidArc applying three 135°arcs with ABC in HCC radiotherapy can achieve better PTV coverage than IMRT with fewer monitor units,shorter treatment time and sparing more normal liver.

Objective To evaluate the role of hippocampal CD200 receptor 1(CD200R1)in peri-operative neurocognitive disorders(PND)in mice.Methods Sixty clean-grade male C57BL/6 mice,aged 9-10 months,weighing 32-38 g,were used in the study.The experiment was performed in two parts.Ex-periment Ⅰ Thirty-six mice were divided into 2 groups(n＝18 each)using a random number table meth-od: control group(group C)and PND group.Group C only received isoflurane anesthesia.Partial left lo-bectomy of the liver was performed under isoflurane anesthesia in group PND.Contextual fear conditioning test was performed at 1,3 and 7 days after surgery,and the freezing time was recorded.The mice were then sacrificed,and the hippocampus was isolated for determination of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)contents(by enzyme-linked immunosorbent assay)and CD200 and CD200R1 expression(by Western blot).ExperimentⅡ Twenty-four mice were divided into 2 groups(n＝12 each)using a random number table method: CD200-Fc group and IgG1-Fc group.Recombinant proteins CD200-Fc and human IgG1-Fc were injected into the lateral cerebral ventricle in CD200-Fc group and IgG1-Fc group,respectively.Partial left lobectomy of the liver was performed after the end of injection.Contextual fear conditioning test was performed at 1 and 3 days after surgery,and the freezing time was recorded.Re-sults Experiment Ⅰ Compared with group C,the freezing time in the contextual fear conditioning test was significantly shortened,and the contents of IL-1β were increased at 1 and 3 days after surgery,the contents of TNF-α were increased at 3 and 7 days after surgery,and the expression of CD200 and CD200R1 was up-regulated at 1 day after surgery in group PND(P＜0.05).ExperimentⅡ Compared with IgG1-Fc group,the freezing time in the contextual fear conditioning test was significantly prolonged at 1 day after surgery in CD200-Fc group(P＜0.05).Conclusion Up-regulated expression of hippocampal CD200R1 is the endogenous protective mechanism of PND in mice.

Objective: To evaluate the role of hippocampal CD200 receptor 1 (CD200R1) in perioperative neurocognitive disorders (PND) in mice. Methods: Sixty clean-grade male C57BL/6 mice, aged 9-10 months, weighing 32-38 g, were used in the study.The experiment was performed in two parts.Experiment Ⅰ Thirty-six mice were divided into 2 groups (n=18 each) using a random number table method: control group (group C) and PND group.Group C only received isoflurane anesthesia.Partial left lobectomy of the liver was performed under isoflurane anesthesia in group PND.Contextual fear conditioning test was performed at 1, 3 and 7 days after surgery, and the freezing time was recorded.The mice were then sacrificed, and the hippocampus was isolated for determination of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) contents (by enzyme-linked immunosorbent assay) and CD200 and CD200R1 expression (by Western blot). Experiment Ⅱ Twenty-four mice were divided into 2 groups (n=12 each) using a random number table method: CD200-Fc group and IgG1-Fc group.Recombinant proteins CD200-Fc and human IgG1-Fc were injected into the lateral cerebral ventricle in CD200-Fc group and IgG1-Fc group, respectively.Partial left lobectomy of the liver was performed after the end of injection.Contextual fear conditioning test was performed at 1 and 3 days after surgery, and the freezing time was recorded. Results: Experiment Ⅰ Compared with group C, the freezing time in the contextual fear conditioning test was significantly shortened, and the contents of IL-1β were increased at 1 and 3 days after surgery, the contents of TNF-α were increased at 3 and 7 days after surgery, and the expression of CD200 and CD200R1 was up-regulated at 1 day after surgery in group PND (P<0.05). Experiment Ⅱ Compared with IgG1-Fc group, the freezing time in the contextual fear conditioning test was significantly prolonged at 1 day after surgery in CD200-Fc group (P<0.05). Conclusion Up-regulated expression of hippocampal CD200R1 is the endogenous protective mechanism of PND in mice.