[en] SiO₂-doped Ba_0.85Sr_0.15TiO₃ (SBST) glass-ceramic (g-c) films with perovskite structure have been prepared on Pt/Ti/SiO₂/Si substrates by sol-gel technique. Differential thermal analysis (DTA), X-ray diffraction (XRD) and atomic force microscopy (AFM) are employed to analyze the synthesize process and microstructure of SBST g-c films. The ferroelectricity and crystallization behavior of SBST films are discussed. It is found that the starting synthesize temperature of SBST15 film is larger than that of pure barium strontium titanate (BST) film for about 60 deg. C. The grain sizes decrease and the ferroelectricity of SBST g-c films is degenerated, but their loss tangent and leakage current density decrease with increasing SiO₂ contents. The temperature coefficient of dielectric (TCD) and the pyroelectric coefficient γ of the films are measured. The results show that TCD and the pyroelectric coefficient γ of SBST5 film at 20-25 deg. C are, respectively, 4.6% deg. C^-1 and 8.1x10^-8 C cm^-2 K^-1, which is about 2/3 value of the pure BST films. BST g-c film with 5 mol% SiO₂ dopant is hopeful to be the advanced candidate material for uncooled infrared focal plane arrays (UFPAs) applied at near room temperature

[en] Objective: To compare the automatic and manual plans of intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma and investigate whether the automatic plan possesses advantages over the manual plan. Methods: Clinical data of 97 nasopharyngeal carcinoma patients were retrospectively analyzed. All patients received IMRT with Eclipse treatment planning system (Version 11.0) using manual optimization. The same plans were optimized successively in Pinnacle³ (version 9.10) treatment planning system using automatic plan software package module (provided by Prof. Zhang XD from MD Anderson Cancer Center). The D₉₅ (dose in 95% of planning target volume, PTV), homogeneity index, conformal index and normal organ dose were statistically compared between two plans. Results: The PTV coverage and homogeneity did not significantly differ between two plans. Compared with the manual plan, the automatic plan could more effectively protect the normal organs. Two plans significantly differed in a majority of organ at risk (OAR). The mean dose was decreased by 270-1870 cGy. Conclusions: For nasopharyngeal carcinoma patients, IMRT via the automatic plan can meet the clinical requirement for target prescription dose and reduce the dose of normal organs. (authors)

[en] Objective: To explore the application value of multi-ISO center planning method in intensity-modulated radiotherapy for carniospinal irradiation. Methods: Ten patients treated with craniospinal irradiation with helical tomotherapy were selected. For these patients, new plans were designed with multi-ISO centers planning method on the treatment planning system (TPS) named Eclipse 11.0. Dose distribution to the tumor, OARs and normal tissue, the treatment time and the monitor units (MUs) of the two plans were compared. Results: The plans designed in two groups satisfied all clinical requirements. For the tumor target (PTV), the difference of D_95% between two groups was not statistical significant, while D_98%, D_2% and HI in HT group were superior to M-ISO group(t = 2.822, 2.333, 4.743, P < 0.05), D_50%, D_mean and CI in M-ISO group were superior to HT group (t = 5.259, 3.685, 8.835, P < 0.05). The dose of OARs such as cochlea, parotid, submandibular gland, thyroid gland and kidney in HT group was lower than M-ISO group (t = 4.365, 5.416, 2.674, 3.077, 2.782, 2.607, 4.659, P < 0.05), and the dose of pancreas and small bowel was higher than M-ISO group(t = 5.265, 5.935, P < 0.05). Differences were not significant for V₅ of normal tissue between two groups; while V₁₀, V₂₀ and V₃₆ of normal tissue in M-ISO group were lower than HT group (t = 3.57, 3.701, 2.602, P < 0.05). M-ISO group reduced 41.0% of the treatment time by average and reduced 94.1% MUs by average. Conclusions: Intensity-modulated radiotherapy for carniospinal irradiation with multi-ISO centers planning method not only met the requirements of clinical dosimetry, but also shorten the treatment time, reduced the damage to the machine. Multi-ISO centers planning method might be promoted as a new design scheme. (authors)

[en] Objective: To compare the effective dose deposited in patients between helical tomotherapy (HT) and multi-ISO radiotherapy (M-ISO) in carniospinal irradiation(CSI). Methods: Nine children with craniospinal irradiation were selected. For these patients, new plans were designed with HT and M-ISO centers planning method on the treatment planning system (TPS). The effective dose of the nine patients from 18 treatment plans were calculated, and the difference of the effective dose between HT and M-ISO was compared using paired t-test. Results: The plans designed in two groups were both satisfied all clinical requirements. For the planning target volume (PTV), no statistically significant difference was found in D_95% between two groups (P > 0.05), while D_98%, D_2% and homogeneity index (HI) in HT group were superior to M-ISO group (t = 2.762, 2.413, 4.563, P < 0.05), D_50%, D_mean and CI in M-ISO group were superior to HT group (t = 5.259, 3.685, 7.815, P < 0.05). HT and M-ISO had different advantages in the protection of the OARs. The effective dose of patients in M-ISO group was superior to HT group (t = 5.921, P < 0.05). Conclusions: HT and M-ISO have different advantages in CSI. The low dose area has greater influence on the effective dose in HT group compared to M-ISO group. The low dose area should be concerned while designing the treatment planning for CSI. (authors)

[en] Objective: To evaluate the efficacy and safety of consolidation chemotherapy alter thoracic radical concurrent chemoradiotherapy for patients with oligometastatic non-small cell lung cancer (NSCLC). Methods: Sixty-six NSCLC patients with more than five metastases from 2008 to 2013 were enrolled, and image-guided radiotherapy with conventionally fractionated or hypofractionated doses were performed for these patients. Platinum-based doublets chemotherapy was applied for both concurrent chemoradiotherapy and consolidation chemotherapy. Short-term outcome, adverse reactions, and survival rate were assessed for the patients after treatment. Results: Sixty-four patients completed the treatment. The median biologically equivalent dose for planning target volume of thoracic primary tumor lesions was 72 Gy, with a median number of chemotherapy cycles of 4. The objective response rate for thoracic lesions was 70%. The follow-up rate was 97%. The 1-, 2-, and 3-year overall survival (OS) rates were 72%, 53%, and 31%, respectively, with a median OS time of 25 months; the 1-, 2-, and 3-year progression-free survival (PFS) rates were 56%, 26%, and 7%, respectively, with a median PFS time of 14 months. The incidence of grade 2-3 acute radiation pneumonitis and radiation esophagitis was 1% and 17%, respectively, and the incidence of grade 3-4 decreases in leukocytes, hemoglobin, and platelet count was 39%, 11%, and 16%, respectively. Conclusions: Radical radiotherapy combined with concurrent and consolidation chemotherapy for oligometastatic NSCLC can achieve good short-term outcome and long-term survival, with tolerable adverse effects. (authors)

[en] Objective: The purpose of this study is to investigate the method to reduce the radiation dose to the neck skin in the Tomotherapy treatment plans for early-stage nasopharyngeal carcinoma. Methods: The 17 patients with early-stage nasopharyngeal carcinoma that have been treated by the Tomotherapy were selected randomly for this skin sparing study. The neck skin sparing region was generated as an internal margin of 3 mm from the out body contour, excluding the intercrossed area with the targets. Candidate patients were planned using TP and NP method respectively: the TP group was planned with the traditional method. The new neck skin region was considered as an organ at risk (OAR) for planning dose constrain in NP group. The dosimetric metrics of targets and OARs, monitor units (MU) and delivery time were compared as the end points of these two groups. Results: The two treatment plan groups satisfied the clinical requirement. There were no significant differences for D₉₈, D₉₅ and D₂ of the targets (P > 0.05). The D_max of brainstem, D_1cc of spinal cord, D_mean of right parotid were higher in NP group than in the TP group (t = 2.47, 2.34, 2.77, P < 0.05). The D_max of left mandible joint was lower than TP group(t = 2.30, P < 0.05). The V₃₀, V₄₀, V₅₀ and V₆₀ of the skin were considerably lower than TP group(t = 8.37, 6.02, 5.82, 4.89, P < 0.05). The mean MU and mean delivery time per fraction of NP group were 6.3% and 8.1% less than that of TP group respectively. Conclusions: The neck skin region should be delineated as an OAR to be spared in the Tomotherapy treatment planning for early-stage nasopharyngeal carcinoma. This method can reduce the skin radiation dose effectively, alleviate the skin reaction, and improve the life quality of patients in radiotherapy. (authors)

[en] Objective: To compare dosimetric parameters between automatic three-dimensional conformal radiotherapy (a3DCRT), inverse three-dimensional conformal radiotherapy (i3DRT), inverse intensity-modulated radiotherapy (iIMRT). Methods: Ten lung cancer patients with a single target and 10 intracranial tumor patients also with a single target, who were treated in our radiotherapy center from 2014 to 2015, were included in the study. Their image data were transferred to RayStation 4.5 via network, and then the treatment plans for a3DCRT, i3DCRT, and iIMRT were designed for the 20 patients. The dosimetric parameters for planning target volume (PTV) and organs at risk (OAR) were compared between the three plans using multiple dependent variables and two dependent variables. Results: For lung cancer patients, iIMRT achieved better results in D_98%, D_50% , D_2%, conformity index (CI), and homogeneity index (HI) than i3DCRT and a3DCRT (P = 0.007, 0.001, 0.002, 0.000, and 0.000), and the CI of a3DCRT was superior to that of i3DCRT (P = 0.000); there were no significant differences in heart D₃₃, spinal cord D_max and D_{1 cm³}, and both lungs between the three plans (P = 0.702, 0.237, 0.163, 0.739, 0.908, 0.832, 0.886, 0.722, 0.429, 0.840, and 0.702). For intracranial tumor patients, there were no significant differences in dosimetric parameters between the three plans, except that the CI of iIMRT and a3DCRT was superior to that of i3DCRT (P = 0. 648, 0.783, 0.256, 0.931, 0.002, and 0.034); there were no significant differences in whole brain irradiation dose between the three plans (P = 0.446, 0.755, 0.772, 0.0266, 0.440, 0.290, and 0.939). Conclusions: For the single target in patients with lung cancer and intracranial tumors, a3DCRT can improve the Cl of PTV compared with i3DCRT, and shows no significant dosimetric disadvantage for OARs compared with iIMRT. Considering the simplicity and low cost of 3DCRT, a3DCRT holds promise as a novel radiotherapy technique. (authors)

[en] Objective: To investigate the radiotherapy (RT) -induced changes in the brain structural network in patients with nasopharyngeal carcinoma (NPC). Methods: Three-dimensional structural magnetic resonance data (3D-T1W) was adopted to investigate the structural network in 103 patients with NPC before and after receiving RT. The structural networks were then reconstructed using 3D-T1W. The radiation-induced changes in topology properties of small world network were analyzed by using graph theoretical analysis. Results: Patients showed small world properties before and after RT. Compared with the pre-RT group, the global and local efficiency were lower, the shortest path length was longer and the clustering coefficient was less in the post-RT group. In addition, the hub regions in the post-RT group were significantly different from those in the pre-RT group, mainly located in the left rolandic operculum, right inferior frontal gyrus, right parahippocampal gyrus, right lingual gyrus, bilateral supramarginal gyrus, left superior temporal gyrus and temporal pole of the right middle temporal gyrus. Conclusion: It is speculated that RT leads to high efficiency of network topology and information transmission, which provides a novel perspective for exploring the RT-induced brain changes, diagnosis of RT-induced injury and evaluation of RT efficacy. (authors)

[en] Objective: To report an implementation method and results of an independent brachytherapy dose verification software (DVS). Methods: The DVS was developed based on Visual C++ and the modular structure design was adopted. The DICOM RT files exported from the treatment planning system (TPS) were automatically loaded into the DVS. The TG-43 formalism was employed for dose calculation. Six cervical cancer patients who underwent brachytherapy were retrospectively selected to test the DVS. Different applicators were utilized for each patient. Dosimetric parameters and γ analysis (0.1 cm, 5%) were used to evaluate the dose difference between the DVS and the TPS. Results: Compared with the TPS dose, the γ pass rates of the doses calculated by the DVS were higher than 98%. For CTV, the dosimetric differences were less than 0.29% and 0.53% for D_100% and D_90%. For bladder, rectum and sigmoid, the agreement of D_0.1cm³, D_1cm³ and D_2cm³ within a 0.5% level. Conclusion: With minimal human-computer interactions, the DVS can verify the accuracy of dose calculated by TPS for brachytherapy. (authors)

[en] Objective: To compare the neck skin dose between fixed-field dynamic intensity-modulated radiation therapy (dlMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT) in the treatment of early-stage nasopharyngeal carcinoma. Methods: A total of 16 early-stage nasopharyngeal carcinoma patients undergoing radiotherapy were enrolled as subjects. The neck skin was delineated by contraction of the outer edge of neck by 3 mm. Dose planning was made by the traditional method (TP group) and a new method (NP group), in which the neck skin was considered as the organ at risk. D_mean and V₅-V₇₀ for the neck skin were recorded. The paired t-test was used to analyze the differences between two plans in each radiotherapy method. An analysis of variance was used to compare the same plan between the three radiotherapy methods. Results: The HT group had significantly higher D_mean and V₅-V₇₀ for the neck skin than the dIMRT group and the VMAT group (P = 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.02). Using dIMRT, the D_mean and V₁₀-V₆₀ for the neck skin were reduced by 7%, 8%, 22%, 25%, 38%, 59%, and 85% in the NP group than in the TP group (P = 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00). Using VMAT, the D_mean and V₂₀-V₄₀ for the neck skin were reduced by 4%, 19%, 29%, and 34% in the NP group than in the TP group (P = 0.02, 0.01, 0.02, 0.01). Using HT, the V₃₀-V₆₀ for the neck skin were reduced by 20%, 29%, 50%, and 67% in the NP group than in the TP group (P = 0.00, 0.00, 0.00, 0.00, 0.03). Conclusions: In the treatment of early-stage nasopharyngeal carcinoma, HT causes a higher radiation dose to the neck skin than dIMRT and VMAT, while dIMRT and VMAT have similar neck skin doses. The neck skin dose can be significantly reduced with the neck skin as the organ at risk. (authors)