Objective To preliminary investigate the clinical efficacy of whole brain simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) in patients diagnosed with brain metastases (BM). Methods Fifty-two cases of BM admitted to our hospital from January 2016 to December 2017 were equally recruited and randomly divided into the observation and control groups. Patients in the observation group were treated with SIB-IMRT,and those in the control group received conventional whole brain radiotherapy (WBRT).The clinical efficacy and prognosis were statistically compared between two groups. Results The ORR in the observation group was 77%,significantly higher than 27% in the control group (P=0.00).The median survival in the observation group was 384 d,significantly longer compared with 211 d in the control group (P=0.00).All patients in both groups successfully completed corresponding treatment. Acute adverse reactions were mainly 1-2 grade reactions. Conclusions SIB-IMRT is an efficacious and safe treatment of BM,which yields tolerable adverse events and deserves application in clinical practice.

Objective To investigate the survival benefits of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) in the treatment of esophageal squamous cell carcinoma (ESCC). Methods From July 2003 to March 2014,1748 patients with ESCC received 3DCRT or IMRT in a single institution were enrolled in this retrospective study. Among them,809 patients received conventional fractionated radiotherapy with the standard prescription dose and 110 patients received SIB-IMRT (SIB-IMRT group).Survival analysis was performed and propensity score matching (PSM 1vs1) was conducted to evaluate and compare the survival benefits between SIB-IMRT and conventional fractionated radiotherapy. Results The baseline characteristics significantly differed between two groups. In the SIB group,the age was significantly younger (64 years vs. 66 years,P=0.001),the percentage of patients with cervical/upper thoracic tumors was considerably higher (53.6% vs. 31.0%,P=0.000) and the proportion of N2 patients was significantly higher (21.8% vs. 13.7%,P=0.027) compared with those in the other group. According to the PSM of 1:1,218 patients were successfully matched. After matching,the clinical data did not significantly differ between two groups. Prior to matching,the median survival time in the standard dose and SIB-IMRT groups were 23 and 21 months (P=0.638).After matching,the median survival time in the SIB-IMRT group was 22 months,significantly longer than 18 months in the standard dose group (P=0.000).Subgroup analysis demonstrated that patients with large tumors (GTV volume>40 cm³) and middle/lower thoracic tumors obtained more survival benefits from SIB-IMRT.The median survival time of patients in the standard dose group was 14 months,significantly shorter than 21 months in the SIB-IMRT group (P=0.001).The median survival time of patients with middle/lower thoracic tumors in the SIB-IMRT group was 17 months,significantly longer than 9 months in the standard dose group (P=0.000).Multivariate analysis using Cox regression model indicated that age,tumor site and radiotherapy modality were the independent prognostic factors. The HR of SIB-IMRT was 0.551(P=0.000),which was a factor for survival benefits. Conclusions SIB-IMRT possesses potential survival benefits for ESCC compared with conventional fractionated radiotherapy. Patients with large tumors and middle/lower thoracic tumors are more prone to obtaining benefits from SIB-IMRT than their counterparts.

Objective To perform 3D dose reconstruction based on electronic portal imaging device (EPID) of linear accelerator for the static intensity-modulated using Edose,a dose verification system, Aiming to assist the radiotherapy professionals to better understand the radiotherapy organs at risk and target dose changes. Methods CBCT image was acquired for patients with head and neck cancer and thoracic cancer once a week for a total of six times. Subsequently,CBCT images and planning CT images were subject to rigid registration and exported to the Edose software. According to the setup error,EPID-based three-dimensional dose reconstruction was performed by using Edose software. The gamma passing rate and dose of different organs at risk (OARs) were analyzed and statistically compared. Results For patients with nasopharyngeal carcinoma,the intra-fractional Dmax of the spinal cord was more significantly fluctuated and higher compared with the planning dose,whereas the intra-fractional Dmax of the brainstem did not significantly fluctuate. The V30 of the parotid gland significantly changed with a maximum increase of 28.69% per fraction. For patients with thoracic tumors,the Dmax of the spinal cord was slightly changed,and the actual doses in the lung and heart were higher than the planning doses. The average deviation of the pulmonary V5 was up to 16.99% between the actual and planning doses with statistical significance (P<0.05).According to the analysis of gamma passing rate,significant dose changes occurring in the OARs were detected in the 16^th fraction for the head and neck cancer and the 24^th fraction for the thoracic neoplasms. Conclusions The dose changes in the OARs can be obtained by reconstructing the EPID-based 3D dose distribution using the Edose software for each fraction,which can better protect the OAR,enhance the coverage of target dose and provide certain reference for dose-guided and self-adaptive radiotherapy.

Objective To compare the dose distribution between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) in patients with brain metastases receiving hippocampus-sparing whole brain radiotherapy. Methods Forty-six patients with brain metastases admitted to our hospital from 2013 to 2016 were recruited in this study. After fusing the CT and MRI images,the hippocampus was delineated on the fusion images. The three-grade hippocampal avoidance regions were created by using a volumetric expansion of 3,5 and 10 mm surrounding the hippocampus. The planning target volume (PTV) was calculated by subtracting the 5-mm expansion surrounding the hippocampus from the whole brain. The prescription dose was 30 Gy/10 fractions. The 7-field IMRT and single arc VMAT were designed for each case. The dose distribution of PTV,hippocampus and other organs at risk (OARs) were evaluated in both plans. Results The PTV was statistically compared between VMAT and IMRT: V95:95.90% and 94.97%(P=0.000); V90:98.17% and 97.48%(P=0.000);CI:0.825 and 0.813(P=0.013);HI:0.277 and 0.289(P=0.025).The hippocampal dose was also compared between VMAT and IMRT:the Dmax of hippocampus was 1698.9 cGy for VMAT and 1784.9 cGy for IMRT (P=0.002).The Dmean of hippocampus was 1183.8 cGy for VMAT and 1112.7 cGy for IMRT (P=0.000).No statistical significance was observed between IMRT and VMAT in protecting the OARs except the chiasma opticum (3262.6 cGy and 3529.3 cGy,P=0.000).The MU and treatment time of VMAT and IMRT were 651 and 2768(P=0.000),and 188 s and 504 s (P=0.000). Conclusions The dose distribution of PTV in VMAT is significantly better than that in IMRT.VMAT is advantageous in protecting the hippocampus than IMRT.VMAT can significantly shorten treatment time and MU and enhance the equipment utilization. Besides,VMAT can achieve the goal of protecting the hippocampus and meet the prescription dose requirement of PTV.

Objective To evaluate the dose variation of target coverage and organs at risk (OARs) among four planning strategies using spot-scanning carbon-ion radiotherapy for non-small cell lung cancer (NSCLC). Methods Ten NSCLC patients utilizing gating motion control were selected to receive dose calculation over multiple acquired 4DCT images. Four optimizing strategies consisted of intensity-modulated carbon-ion therapy (IMCT-NoAS),IMCT combined with internal gross tumor volume (IGTV) assigned muscle (IMCT-ASM),single beam optimization (SBO)(SBO-NoAS) and SBO combined with IGTV assigned muscle (SBO-ASM).The initial plan was re-calculated after the 4DCT data were reviewed and then compared with the initial plan in the dosimetry. Results For re-calculation plans with two reviewing CTs,all four strategies yielded similar planning target volume (PTV) coverage. Merely IMCT-NoAS strategy presented with relatively significant variations in dose distribution. Dose variation for OARs between initial and re-calculated plans:for all four strategies,V20 of ipsilateral lung was increased by approximately 2.0 Gy (relative biological effective dose,RBE),V30 of heart was increased by approximately 1.0 Gy (RBE) for both IGTV assigned muscle strategies,whereas decreased by approximately 0.2 Gy (RBE) for both IGTV non-assigned muscle strategies. The maximum dose of spinal cord was changed by 2.5 Gy (RBE). Conclusions Carbon-ion radiotherapy is sensitive to the anatomic motion within the tumors along the beam path. When the tumor motion along the head-foot (H-F) direction exceeds 8 mm,SBO-ASM strategy provides better dose coverage of target. Strategies with IGTV assignment may result in dose overshoot to a position deeper than the initial planning dose distribution.

Objective To propose a method to improve the efficiency and accuracy of the Pinnacle treatment planning system in searching for a certain patient. Methods The original Pinnacle system was modified by adding a button of “Search Patient” in the window of"Patient Select" to call a self-built window of"Search Patient by MRN or Name". After inputting the patient′s Medical Record Number or Name, a self-built script file was called to quickly find and locate the patient′s record. Results The patient′s MRN or Name was input in the window of “Search Patient by MRN or Name”,and then input “Enter” or clicked the button of Search to rapidly identify the patient and enhance the search efficiency. Conclusion The openness and script of the Pinnacle system can be utilized to modify and improve and supplement the existing functions.

The incidence of small cell lung cancer (SCLC) is relatively low, which approximately accounts for 13%-20% of all types of lung cancers. SCLC is characterized by high-degree malignancy and high metastasis and recurrence rates within a short period of time. Upon the confirmed diagnosis, limited-stage SCLC approximately accounted for 30% of SCLC and merely 5% of these patients were eligible for surgery. Over half of the patients who obtained complete remission after chemoradiotherapy presented with brain metastases. The postoperative incidence of brain metastases in patients with stage Ⅰ, Ⅱ and Ⅲ SCLC was 6%-14%,13%-38% and 11%-36%, respectively. Prophylactic cranial irradiation (PCI) can enhance the overall survival rate of patients with complete remission after chemoradiotherapy and reduce the incidence of brain metastasis, which is a pivotal part of comprehensive treatment of limited-stage SCLC. However, the application of PCI remains controversial in clinical practice and the clinical efficacy for patients with surgically resected SCLC significantly varies. In this article, literature review was conducted and the research progress in this field was summarized.