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Objective:To observe the feasibility of magnetic resonance (MR)-guided stereotactic body radiotherapy (SBRT) for non-small cell lung cancer, and analyze the dosimetric differences in the presence or absence of magnetic field.Methods:Three patients with non-small cell lung cancer were prospectively treated with MR-guided linac (MR linac) for SBRT, and the dose was calculated with or without magnetic field models. The differences of dose distribution with or without magnetic field models were compared. At the same time, the target coverage, plan pass rate and treatment time were described, and the complexity of the conventional accelerator backup plan and the magnetic field model were compared.Results:The treatment time of 3 patients was (36.67±6.11) min, and the average time of online adaptive planning was (14.4±1.7) min, which was basically tolerated by patients. The treatment plan pass rate (3%/3 mm) was 98.9%, the Gamma pass rate (3%/3 mm) of the online plan during treatment was 98.5% and the target coverage was 99.1%, which met the clinical needs. The dose in the low dose area of the lung was slightly lower than that in the case without magnetic field, whereas the dose in ribs and skin was slightly higher than that in the plan without magnetic field. The number of machine unit (MU) for online adaptive plan was slightly higher than that of the reference plan, and the number of MU for the conventional accelerator standby treatment plan was significantly lower than that of the MR linac plan under the same target coverage. The follow-up results showed that there was no adverse reaction, and the short-term efficacy was partially relieved.Conclusions:In the case of considering the influence of magnetic field, the treatment plan meeting the clinical needs can be obtained. It is proven that SBRT radiotherapy for lung cancer guided by magnetic resonance accelerator is feasible, whereas the treatment time and process are complex.
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Objective:To investigate the effectiveness of abdominal compression in tumor motion and the target volume, and analyze the suitable margins of planning target volume (PTV) for patients treated with lung-SBRT based on 4DCT.Methods:Patients diagnosed with peripheral pulmonary tumor were enrolled. The patients were divided into the whole group, upper-middle-lobe group (group A) and the lower-lobe group (group B). Each patient underwent 3DCT, 4DCT with abdominal compression (4DCT com) and 4DCT with free breath (4DCT free) scans. The GTVs were delineated and IGTVs on these images. PTV MIP 5 mm, PTV MIP 4 mm, PTV MIP 3 mm were constructed with a 5, 4, 3 mm margin in left-right (LR), anterior-posterior (AP) directions and cranial-caudal (CC) directions. Results:The median motion vector with compression reduced by 30.92% in whole group, increased by 3.42% in group A and reduced by 18.80% in group B, respectively. And there were no significant differences of TMA LR, TMA AP, TMA CC and motion vector by the Wilcoxon test ( P>0.05). The median sizes of IGTV MIP com , IGTV MIP free and IGTV10 com, IGTV10 free were 4.01, 5.36 cm 3and 6.59, 7.65 cm 3, with statistically significant difference ( Z=-3.45, -3.14, P<0.01). The median ratio of DI of IGTV CBCT com in PTV MIP 5 mm, PTV MIP 4 mm and PTV MIP 3 mm≥95% was 100%, 100% and 83.33%, respectively. Conclusions:The patients′ respiratory pattern changed with abdominal compression and abdominal compression is useful in reducing the size of IGTV MIP and IGTV10, which could reduce the target volume and protect the normal tissue. Adding a 4 mm margin to IGTV MIP com based on 4DCT account for respiration in SBRT is a tendency for precise radiotherapy.
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Objective:To assess the feasibility of delayed-enhancement MRI in contouring the lumpectomy cavity (LC) for patients with invisible seroma or a low cavity visualization score (CVS≤2) in the excision cavity after breast-conserving surgery (BCS).Methods:Twenty-six patients with stage T 1-2N 0M 0 who underwent prone radiotherapy after BCS were recruited. The LC delineated on CT simulation images was denoted as LC CT. The LCs delineated on T 2WI, as well as on different delayed phases (2-, 5-and 10-minute) of delayed-enhancement T 1WI were defined as LC T2, LC 2T1, LC 5T1 and LC 10T1, respectively. Subsequently, the volumes and locations of the LCs were compared between CT simulation images and different sequences of MR simulation images using deformable image registration. Results:The volumes of LC T2, LC 2T1, LC 5T1 and LC 10T1 were all larger than that of LC CT. A statistical significance was found between the volume of LC CT and those of LC 2T1 or LC 5T1, respectively (both P<0.05). The conformal index (CI), degree of inclusion (DI), dice similarity coefficient (DSC) and the distance between the center of mass of the targets (COM) of LC CT-LC 10T1 were better than those of LC CT-LC T2, LC CT-LC 2T1 and LC CT-LC 5T1, however, there was no statistical difference among them (all P>0.05). Conclusions:It is feasible to delineate the LC based on prone delayed-enhancement MR simulation images in patients with low CVS after BCS. Meanwhile, the LCs derived from prone delayed-enhancement T 1WI of 10-minute are the most similar with those derived from prone CT simulation scans using titanium clips, regardless of the volumes and locations of LCs.
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Objective:To investigate the application value of 18F-FDG PET-CT combined with MRI in the radiotherapy for esophageal carcinoma by comparing the differences in the gross target volume (GTV), position length delineated on the end expiratory (EE) phase of 4DCT, PET-CT and T 2-weighted MRI (T 2W-MRI). Methods:Twenty-six patients with thoracic esophageal cancer scheduled to receive concurrent chemoradiotherapy sequentially underwent 3DCT, 4DCT, PET-CT and enhanced MRI for thoracic localization. All images were fused with the 3DCT images by deformable registration. GTV CT, GTV 50% GTV PET2.5, GTV MRI and GTV DWI were delineated on 3DCT, the EE phase of 4DCT images, PET-CT with the thresholds of SUV≥2.5, T 2W-MRI and diffusion-weighted images, respectively. Results:GTV PET2.5 was significantly larger than GTV 50% and GTV MRI ( P<0.001 and P=0.008), whereas the volume of GTV MRI was similar to that of GTV 50%( P=0.439). Significant differences were observed between the CI of GTV MRI to GTV 50% and GTV PET2.5 to GTV 50%( P=0.004). The conformity indexes (CIs) of GTV MRI to GTV CT and GTV PET2.5 to GTV CT were statistically significant ( P=0.004 and P=0.039). The CI of GTV MRI to GTV PET2.5 was significantly smaller than that of GTV MRI to GTV 50%, GTV MRI to GTV CT, GTV PET2.5 to GTV 50% and GTV PET2.5 to GTV CT ( P=0.000-0.021). The length of gastroscopy was similar to those of GTV PET2.5 and GTV DWI (both P>0.05), and there was no significant difference in the length between GTV PET2.5 and GTV DWI ( P=0.072). Conclusion:GTV MRI yields significantly different volume and poor spatial matching compared with GTV PET2.5. The application of PET-CT combined with MRI under respiratory gating system in the delineation of GTV should be used with caution in thoracic squamous esophageal cancer. MRI-DWI can replace PET-CT to help determine the upper and lower boundaries of GTV based on CT images.
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Objective@#To explore the differences and correlation between the target volumes based on deformation registration (DIR) using preoperative prone diagnostic magnetic resonance (MR) imaging and postoperative prone computed tomography (CT) simulation imaging for patients undergoing breast-conserving surgery (BCS).@*Methods@#Eighteen breast cancer patients suitable for external-beam partial breast irradiation (EB-PBI) after BCS were enrolled. Preoperative prone diagnostic MR and postoperative prone CT scan sets were acquired during free breathing for all patients. The gross tumor volume (GTV) delineated on the preoperative diagnostic MR images was defined as GTVMRI, the clinical target volumes (CTVMRI+ 1 and CTVMRI+ 2)were defined as 10 and 20 mm margins around the GTVMRI, and the planning target volume (PTVMRI+ 1 and PTVMRI+ 2) were defined as 15 and 25 mm margins around the GTVMRI, respectively. Tumor bed (TB) delineated on the postoperative prone CT simulation images acquired during free breathing was defined as GTVTB, CTV and PTV were defined as 10 and 15 mm margins around the GTVTB, respectively. The target volume of the whole breast contoured on the MR and CT images were defined as CTVBreast-MRI and CTVBreast-CI, respectively. The MR and CT images were registered deformably in MIM software system.@*Results@#The GTVTB, CTVTB and PTVTB were significantly greater than GTVMRI, GTVMRI+ 1 and PTVMRI+ 1, respectively (Z=-3.593, -3.593, -2.983, P<0.05). Meanwhile, the CTVTB and PTVTB were significantly less than the CTVMRI+ 2 and PTVMRI+ 2, respectively(Z=-2.722, -2.853, P<0.05). The conformal index (CI) and degree of inclusion (DI) of GTVTB-GTVMRI, GTVTB-CTVMRI+ 1, CTVTB-GTVMRI and CTVTB-GTVMRI+ 1 based on center-coincidence of the compared targets were better than those based on DIR of the thorax(Z=-3.724、-3.724、-2.591、-3.593, P<0.05; Z=-3.724、-3.724、-3.201、-3.724, P<0.05).@*Conclusions@#For the patients enrolled for prone EB-PBI, target volumes delineated on the preoperative prone MR images were significantly smaller compared to that on the postoperative prone CT images, but a statistically significant positive correlation was found between the MR and CT target volumes. There were still relatively poor spatial overlap whether for the whole breast or the targets between the preoperative prone diagnostic MR images and the postoperative prone simulation CT images based on DIR. Therefore, it is infeasible to guide postoperative EB-PBI target delineation using the preoperative prone diagnostic MR images.
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Objective To detect the changes of heart volume during concurrent chemoradiotherapy for esophageal cancer based on repeated enhanced 4DCT.Methods Patients with squamous cell esophageal cancer underwent repeated enhanced 4DCT and 3DCT scans before and after 10,20 and 30 fractions of radiotherapy,respectively.The heart was contoured on 3DCT,end expiratory (EE) and maximum intensity projection (MIP) of 4DCTimages.The changes in theheart volume,blood pressure.and heart rate were statistically compared at different time points.Results A total of forty-six patients completed 4 fractions of 3DCT and enhanced 4DCT scans.Compared with the initial values,the heart volume was significantly decreased by 3.27％,4.45％ and 4.52％ after 10 fractions of radiotherapy,and reduced by 6.05％,5.64％ and 4.51％ following 20 fractions of radiotherapy on 3DCT,EE and MIP,respectively (P=0.000-0.027).The heart volume after 30 fractions of radiotherapy did not significantly differ from the initial volume (P＞ 0.05).After radiotherapy,there was a significant decrease inboth systolic and diastolic blood pressure (P =0.000 and P =0.009) and a significant ‖ increase in the heart rate (P=0.0 0 1) compared with those measured before radiotherapy.Conclusions Enhanced 4DCT scan can clearly reflect the changes of heart volume throughout concurrent chemoradiotherapy.The heart volume starts to shrink during the early stage of radiotherapy and continue to decrease until the middleand late-stage,whereas it restores to the initial volume after radiotherapy.Simultaneously,blood pressure declines and heart rate is accelerated during radiotherapy.
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Objective To investigate the difference of target volumes and dosimetric parameters between supine and prone positions for external-beam partial breast irradiation (EB-PBI) after breastconserving surgery (BCS).Methods Thirty breast cancer patients with T1N0M0 stage who underwent three-dimensional conformal radiation therapy (3D-CRT) EB-PBI after BCS were enrolled from July 2016 to April 2017.Supine and prone scan sets were acquired during free breathing for all patients.Target volumes and organs at risk (OARs) including heart,ipsilateral lung and bilateral breast were contoured by the same radiation oncologist.The tumor bed (TB) was determined based on surgical clips.The clinical target volume (CTV) consisted of the TB plus 1.0 cm margin and the planning target volume (PTV) was CTV plus 0.5 cm.Dosimetric parameters for target volumes and OARs were compared between supine and prone positions.Results The median volumes of the TB,the CTV and the PTV in supine were 14.40 cm3,57.35 cm3,108.85 cm3 and 14.10 cm3,62.60 cm3,113.70 cm3 for prone positions,respectively.The CTV and PTV in prone position were significantly greater than those in supine position,respectively (Z=-3.01,-2.87,P ＜0.05),but the TBs were not statistically different (P ＞0.05).The median homogeneity indexs (HI) in supine position was less than those in prone position (Z =-3.137,P ＜0.05),while the mean conformal indexs (CI) was increased with prone positioning (t =9.034,P ＜ 0.05).The mean dose (D) to the heart in the supine position was significantly lower than that in prone (0.34 and 1.19 Gy,Z =-4.12,P ＜0.05).The D to the ipsilateral lung in the prone position was significantly lower than that in supine (1.59 and 1.72 Gy,Z =-2.18,P ＜ 0.05).There was not significantly statistical difference for the D to the ipsilateral breast between two positionings (10.01 and 10.40 Gy,P ＞0.05).Conclusions It was feasible to carry out 3D-CRT EB-PBI in prone position in free breathing for Chinese breast cancer patient,with primary advantages of better CI and the significantly lower radiation dose to the ipsilateral lung.
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Objective To compare the dosimetry of three different radiation therapy plans [threedimensional conformal radiation therapy (3DCRT),intensity modulated radiation therapy (IMRT),intensity modulated arc radiotherapy (IMAT)].Methods Selected 15 cases with middle thoracic esophageal cancer,Varian Eclipse 8.6 planning systems were designed with 3DCRT,IMRT,IMAT,3DCRT using 5-8 coplanar radiation fields,IMRT using 7 coplanar radiation fields,IMAT using 2 radians.Three planned dose difference were compared.Results Compared with 3DCRT,IMRT and IMAT were better with heterogeneity index (HI),conformality index (CI),VPTV 95 ％,V5,V20,V35 of total lung,and V30 of heart (t =2.531,P＜ 0.05).There was no statistically significant difference for the V10,V15,V25,V30 mean dose of total lung,the mean dose of heart,the maximum dose of spinal cord,and the minimum dose of PTV among the three plans (t =1.325,P ＞0.05).Conclusion IMAT and IMRT are similar in the middle thoracic esophageal cancer radiotherapy target volume dose coverage and organs at risk protection,they are better than 3DCRT.IMAT in the monitor units and delivery time are less than IMRT.
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Radiotherapy is an effective mean of treatment of gastric cancer. Combination of radiotherapy and chemotherapy in gastric cancer preoperative, postoperative and palliatie treatments can increase the local control rate and the survival rate of gastric cancer patients. With the development of three-dimensional conformal and intensity modulated radiotherapy, the radiotherapy is being more extensively applied in the comprehensive treatment of gastric cancer.
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Triptolide (TL) is a major active component extracted from Chinese traditional herb Tripteryginm wil-fordii Hook. In this article, the effects of TL on mixed lymphocyte culture (MLC),suppressor T cell(Ts) activity, delayed type hypersensitivity (DTH) reaction, IL - 2 secretion activity and Th/Ts ratio were evaluated, In vitro TL 0. 5~10 ?g ? L-1suppressed one-way MLC,Lymphocytes induced in first MLC with TL of 5,10 ?g ? L-1 suppressed the second MLC after irradiation with 3000 rad 60Co source. This suggests that TL may induce Ts cell-s. In vivo, DTH reaction sensitized to dinitrofluo-robenzene (DNFB) monitored by the increase in weight of the ears challenged with antigen was suppressed by TL at doses of 0. 12 to 0. 50 mg ? kg-1(ip,qd?5) and the IL -2 activity secreted by spleen cells of these mice was inhibited at doses of 0. 25 and 0. 5 mg ? kg-1. TL 0. 25, 0. 5 mg ? kg-1(ip,qd?8) also had prominent suppres-sive effects on enhanced DTH reaction which was induced by cyclophosphamide(250 mg ? kg-1,ip). Th/Ts ratio of mouse thymus cells were reduced after given 0. 25 mg ? kg-1 of TL for 5 consecutive days. The above-mentioned data suggest that TL has suppressive effects on cellular immunity function and the suppressive mechanism may be related to the suppression of Th cells and IL-2 secretion activity and the induction of Ts cells.