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Abstract: Ceramic matrix composites based on cubic boron nitride with a TaC binder phase are sintered under conditions of high pressure and high temperature. The sintering is carried out in a high-pressure apparatus of the toroid type in the temperature range of 1450–2450°C. It is shown that a chemical reaction between components of the mixture with the formation of TaB2 takes place at a sintering
Lessons Learned: It is possible to plan and treat some patients with stereotactic body radiotherapy (SBRT) in a timely fashion in an acute setting. Advanced and, in some indications, already implemented technologies such as SBRT are difficult to test in a randomized trial. Background: Stereotactic body radiotherapy (SBRT) in metastatic spinal cord compression (MSCC) could be an alternative to deco
Background: The purpose of this study was to examine the occurrence of cerebral infarction (ischemic stroke), in a large combined cohort of patients with anterior skull base meningiomas, pituitary adenomas and craniopharyngiomas, after fractionated stereotactic radiation therapy (FSRT). Material and Methods: All patients, 18 years and older, with anterior skull base meningiomas, pituitary adenomas
In this paper we present a method for simultaneously segmenting brain tumors and an extensive set of organs-at-risk for radiation therapy planning of glioblastomas. The method combines a contrast-adaptive generative model for whole-brain segmentation with a new spatial regularization model of tumor shape using convolutional restricted Boltzmann machines. We demonstrate experimentally that the meth
Introduction: In this study we investigate the risk of radiation-induced serious adverse event of the spine in a large cohort of consecutive retreated patients with palliative radiotherapy (RT) for metastatic cancer in the spine. Methods and materials: From 2010 to 2014, 2387 patients received spinal irradiation with a palliative intent for metastatic spinal cord compression at our institution. T
Background: We sought to assess the influence of the clinical introduction of new radiotherapy technologies on glioblastoma patients’ outcomes. Methods: Newly diagnosed glioblastoma patients treated with 60 Gy and temozolomide (2005–2014) were analyzed. The patients’ GTV and CTV were defined based on MR (n = 521) or FET-PET/MR (n = 190), and were treated using conformal radiotherapy (CRT, n = 159)
Background: Recurrence in glioblastoma patients often occur close to the original tumour and indicates that the current treatment is inadequate for local tumour control. In this study, we explored the feasibility of using multi-modality imaging at the time of radiotherapy planning. Specifically, we aimed to identify parameters from pre-treatment PET and MRI with potential to predict tumour recurr
Background: To determine if reduced dose delivery uncertainty is associated with daily image-guidance (IG) and Prostate Specific Antigen Relapse Free Survival (PRFS) in intensity-modulated radiotherapy (IMRT) of high-risk prostate cancer (PCa). Methods: Planning data for consecutive PCa patients treated with IMRT (n = 67) and IG-IMRT (n = 35) was retrieved. Using computer simulations of setup erro
Introduction The purpose of this study was to evaluate the safety and efficacy of PET and MRI guided re-irradiation of recurrent high-grade glioma (HGG) and to assess the impact of radiotherapy dose, fractionation and irradiated volume. Material and methods Patients with localized, recurrent HGG (grades III-IV) and no other treatment options were eligible for a prospective phase I trial. Gross tum
BACKGROUND: Hypoxia and increased glycolytic activity of tumors are associated with poor prognosis. The purpose of this study was to investigate differences in radiotherapy (RT) dose painting based on the uptake of 2-deoxy-2-[(18) F]-fluorodeoxyglucose (FDG) and the proposed hypoxia tracer, copper(II)diacetyl-bis(N(4))-methylsemithiocarbazone (Cu-ATSM) using spontaneous clinical canine tumor model
Objective. The aim of this study was to prospectively assess the development of 24 urinary, gastrointestinal and sexual symptoms in patients with prostate cancer (PCa) during and after image-guided volumetric modulated arc therapy (IG-VMAT). Material and methods. A total of 87 patients with PCa participated in this study. The patients were asked to complete a modified version of the Prostate Cance
Results: The average gamma index failure rate (2% and 2 mm criteria) was < 0.01% with amplitude gating for all patients, and < 0.1% with phase gating and < 3.7% with MLC tracking for three of the four patients. One of the patients had an average failure rate of 15.1% with phase gating and 18.3% with MLC tracking.With no motion compensation, the average gamma index failure rate ranged from 7.1% to
To determine visual outcome including the occurrence of radiation induced optic neuropathy (RION) as well as tumor control after fractionated stereotactic radiation therapy (FSRT) of benign anterior skull base meningiomas or pituitary adenomas. Thirty-nine patients treated with FSRT for anterior skull base meningiomas and 55 patients treated with FSRT for pituitary adenomas between January 1999 an
Treatment of cervical cancer, one of the three most commonly diagnosed cancers worldwide, often relies on delineations of the tumour and metastases based on PET imaging using the contrast agent 18F-Fluorodeoxyglucose (FDG). We present a robust automatic algorithm for segmenting the gross tumour volume (GTV) and metastatic lymph nodes in such images. As the cervix is located next to the bladder and
Background. Flattening filter-free (FFF) beams are an emerging technology that has not yet been widely implemented as standard practice in radiotherapy centers. To facilitate the clinical implementation of FFF, we attempted to elucidate the difference in plan quality and treatment delivery time compared to flattening filter beams (i.e. standard, STD) for several patient groups. We hypothesize that
Background: 18F-FDG PET/CT (FDG PET/CT) used in radiotherapy planning for extra-cerebral malignancy may reveal metastases to distant sites that may affect the choice of therapy. Aim: To investigate the role of FDG PET/CT on treatment strategy changes induced by the use of PET/CT as part of the radiotherapy planning. ‘A major change of treatment strategy’ was defined as either including more lesion
Purpose We evaluated the feasibility of treating patients with locally advanced non-small cell lung cancer (NSCLC) with pencil beam scanned intensity modulated proton therapy (IMPT) in breath-hold. Methods and Materials Fifteen NSCLC patients who had previously received 66 Gy in 33 fractions with image guided photon radiation therapy were included in the present simulation study. In addition to a
Purpose Prostate motion during radiation therapy (ie, intrafraction motion) can cause unwanted loss of radiation dose to the prostate and increased dose to the surrounding organs at risk. A compact but general statistical description of this motion could be useful for simulation of radiation therapy delivery or margin calculations. We investigated whether prostate motion could be modeled with a ra
Purpose The purpose of this study was to estimate the uncertainty in voluntary deep-inspiration breath-hold (DIBH) radiotherapy for locally advanced non-small cell lung cancer (NSCLC) patients. Methods Perpendicular fluoroscopic movies were acquired in free breathing (FB) and DIBH during a course of visually guided DIBH radiotherapy of nine patients with NSCLC. Patients had liquid markers injected
Introduction:The breath-hold technique inter alia has been suggested to mitigate the detrimental effect of motion on pencil beam scanned (PBS) proton therapy dose distributions. The aim of this study was to evaluate the robustness of incident proton beam angles to day-to-day anatomical variations in breath-hold.Materials and methods: Single field PBS plans at five degrees increments in the transve
