胸段食管癌累及野放疗与扩大野放疗对危及器官的辐射剂量学分析

目的 研究胸段食管癌逆向调强放射治疗（IMRT）中累及野照射与扩大野照射对危及器官（OAR）受照剂量的影响。方法 40例胸段食管癌患者分别行累及野靶区勾画和扩大野靶区勾画并勾画危及器官，制定IMRT计划，评估2个计划的靶区适形指数（CI）和均匀性指数（HI）及危及器官的剂量学参数，剂量学参数比较采用配对t检验。结果 2种计划的PTV均能满足处方剂量要求，PTV在CI、HI上相近（P = 0.317、0.130）。两组间平均肺剂量、两肺V₅、两肺V₂₀、两肺V₃₀、脊髓D_mean、心脏D_mean、心脏D_max、心脏V₃₀、心脏V₄₀、心脏V₆₀差异均存在统计学意义（P < 0.01）。结论 胸段食管癌患者行累及野照射与扩大野比较，可降低正常器官的受照剂量，从而降低放射性损伤风险。     

Surgical resection after neoadjuvant durvalumab and radiation is feasible and safe in non–small cell lung cancer: Results from a randomized trial

ObjectiveSeveral trials have recently reported the safety of pulmonary resection after neoadjuvant immunotherapy with encouraging major pathological response rates. We report the detailed adverse events profile from a recently conducted randomized phase II trial in patients with resectable non–small cell lung cancer treated with neoadjuvant durvalumab alone or with sub-ablative radiation.MethodsWe conducted a randomized phase II trial in patients with non–small cell lung cancer clinical stages I to IIIA who were randomly assigned to receive neoadjuvant durvalumab alone or with sub-ablative radiation (8Gyx3). Secondary end points included the safety of 2 cycles of preoperative durvalumab with and without radiation followed by pulmonary resection. Postoperative adverse events within 30 days were recorded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0).ResultsSixty patients were enrolled and randomly assigned, with planned resection performed in 26 patients in each arm. Baseline demographics and clinical variables were balanced between groups. The median operative time was similar between arms: 128 minutes (97-201) versus 146 minutes (109-214) (P = .314). There was no 30- or 90-day mortality. Grade 3/4 adverse events occurred in 10 of 26 patients (38%) after monotherapy and in 10 of 26 patients (38%) after dual therapy. Anemia requiring transfusion and hypotension were the 2 most common adverse events. The median length of stay was similar between arms (5 days vs 4 days, P = .172).ConclusionsIn this randomized trial, the addition of sub-ablative focal radiation to durvalumab in the neoadjuvant setting was not associated with increased mortality or morbidity compared with neoadjuvant durvalumab alone.     

Improvement of patient localization repeatability using a light-section based optical surface guidance system in a pre-positioning procedure

PurposeSurface-guided radiotherapy is useful for the pre-positioning and monitoring of radiotherapy. The purpose of this study was to investigate the impact of surface guidance on the repeatability of patient localization and to estimate the specific point at which high positional errors occur.Materials and methodsTen patients without the VOXELAN system (non-VXLN group) and 10 patients with the VOXELAN as the pre-positioning procedure (VXLN group) were included in this analysis. Twelve regions of interest (ROI) were defined in all the patients to verify any misalignment during radiotherapy. Thirteen ROIs were defined on the isocenter.ResultsCompared with the non-VXLN group, the translational positional errors of the VXLN group were the same for all the ROIs. The mean translational positional errors of the VXLN group in the longitudinal direction were approximately 0.1 mm, and the standard deviation was the largest among the three directions in all the ROIs. The magnitude of the standard deviation in the non-VXLN group varied independently of the ROI and direction. The standard deviations of the VXLN group in the longitudinal direction were large in all the ROIs, while the standard deviations in the vertical and lateral directions were small.ConclusionPre-positioning with a surface guidance system reduced the body twist and rotation, which could not be corrected by image-guided radiotherapy alone. Since the VOXELAN can detect positioning errors quickly and without additional radiation exposure to the patient, it can be used as a tool for pre-positioning in radiotherapy.     

脾脏ARFI弹性联合血小板计数预测乙肝肝硬化食管静脉曲张的价值

目的 本研究应用声辐射力脉冲成像(Acoustic Radiation Force Impulse ARFI)技术对慢性乙型肝炎肝硬化患者进行脾脏弹性检测和分析,探讨和对比脾脏ARFI弹性及脾脏ARFI弹性联合血小板计数(Platelet Count PC)在预测乙肝肝硬化食道静脉曲张的临床应用价值。方法 对232例慢性乙型肝炎肝硬化患者应用ARFI技术检测脾脏实时超声弹性,并测量PC,所有患者均于检测前后一周内行胃镜检查明确食管静脉曲张情况,以胃镜结果为金标准,应用受试者工作特征(receiver operating characteristic, ROC)曲线比较脾脏ARFI弹性、PC、及脾ARFI弹性联合PC诊断肝硬化食管静脉曲张的临床价值。结果 食道静脉曲张组脾脏ARFI弹性和PC分别为3.52(3.16-3.87)m/s 和62(41-88.25),无食道静脉曲张组脾脏ARFI弹性和PC分别为2.91(2.35-3.35)m/s和129.5(87.25-196.25)。脾脏ARFI弹性和PC在两组间比较的差异均具有统计学意义(P＜0.001 )。单独脾脏ARFI弹性及脾脏ARFI弹性联合PC的ROC曲线下面积分别为0.76和0.83,差异具有统计学意义(P = 0.0021)。结论 脾脏ARFI弹性测值联合PC较单纯脾脏ARFI弹性能更准确的无创预测慢性乙型肝炎肝硬化食管静脉曲张的存在,具有良好的临床应用前景。     

A High Order Bound Preserving Finite Difference Linear Scheme for Incompressible Flows

We propose a high order finite difference linear scheme combined with a high order bound preserving maximum-principle-preserving (MPP) flux limiter to solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear and WENO type schemes, with and without the MPP flux limiter, will demonstrate the good performance of our proposed approach.     

RNA相关的低剂量辐射响应标志物

电离辐射会对人体造成损伤,根据受照剂量、时间等因素的不同可诱发多种生物效应。目前对于低剂量辐射产生的健康效应仍有争议,筛选对低剂量敏感的辐射响应生物标志物,对于完善低剂量辐射生物效应机制、拓宽低剂量辐射在临床中的应用均具有重要理论意义。综述探讨各核糖核酸(RNA)在低剂量辐射反应中的变化及其对辐射敏感性的调节作用,同时评估各RNA作为低剂量辐射响应标志物的潜力。     

What information can we gain from performing adaptive radiotherapy of head and neck cancer patients from the past 10 years?

The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients’ evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients’ quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.     

Evolving Radiotherapy Techniques in Paediatric Oncology

Aims

Childhood cancer is rare and survival of childhood cancer has increased up to 80% at 5 years after diagnosis. Radiotherapy is an important element of the multimodal treatment concept. However, due to growing tissue, children are particularly sensitive to radiation-related side-effects and the induction of secondary malignancies. However, radiotherapy techniques have continuously progressed. In addition, modern treatment concepts have been improved in order to minimise long-term effects. Today, radiotherapy is used for various tumour types in childhood, such as sarcomas and tumours of the central nervous system.