523 research outputs found

    Integrating Incidence Angle Dependencies Into the Clustering-Based Segmentation of SAR Images

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    Synthetic aperture radar systems perform signal acquisition under varying incidence angles and register an implicit intensity decay from near to far range. Owing to the geometrical interaction between microwaves and the imaged targets, the rates at which intensities decay depend on the nature of the targets, thus rendering single-rate image correction approaches only partially successful. The decay, also known as the incidence angle effect, impacts the segmentation of wide-swath images performed on absolute intensity values. We propose to integrate the target-specific intensity decay rates into a nonstationary statistical model, for use in a fully automatic and unsupervised segmentation algorithm. We demonstrate this concept by assuming Gaussian distributed log-intensities and linear decay rates, a fitting approximation for the smooth systematic decay observed for extended flat targets. The segmentation is performed on Sentinel-1, Radarsat-2, and UAVSAR wide-swath scenes containing open water, sea ice, and oil slicks. As a result, we obtain segments connected throughout the entire incidence angle range, thus overcoming the limitations of modeling that does not account for different per-target decays. The model simplicity also allows for short execution times and presents the segmentation approach as a potential operational algorithm. In addition, we estimate the log-linear decay rates and examine their potential for a physical interpretation of the segments

    Radiotherapy: An Alternative to Surgery

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    Many major technical developments have occurred during the last decades in radiotherapy: our efficacy has improved with less toxicity. Nowadays, it allows us to challenge the role of surgery as a local modality for lung cancer both for early, advanced and even metastatic disease. In the present paper, we will mainly discuss the role of SBRT for stage I lung cancer, the place of conventional radiotherapy for stage III and we will review the current treatment of small cell lung cancer from a radiation oncologist perspective

    Long Term Effects of Radiation and Combined Modalities on Mouse Lung

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    The lung appears to be the major dose-limiting organ in radiation of the thorax. Early responses (\u3c1 week) involve the type II pneumocyte and increased surfactant biosynthesis and secretion. Later changes, which appear to be related to the surfactant response, lead to classical radiation pneumonitis, which is often fatal. Animals which survive radiation pneumonitis develop progressive fibrosis, a late-appearing response, which reduces compliance and available air space, and is usually fatal. This study centers on the fine structural changes in the lungs of LAF1 mice, 63 weeks following various radiation exposures (5-13 Gy). Doses which are subthreshold in evoking surfactant and pneumonitic responses precipitate fibrosis and atelectasis by 63 weeks, and involve type II pneumocyte sloughing and degeneration. Of the two major deterrents to lung irradiation (pneumonitis and fibrosis), these results suggest that fibrosis always follows pneumonitis, but pneumonitis is not a necessary preliminary step to fibrosis. Bleomycin elicits several morphological alterations characteristic of radiation, and, when combined with the latter, appears to exacerbate radiation effects

    European Lung Cancer Working Party. Clinical Practice Guidelines. Small Cell Lung Cancer: V. Extensive disease

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    The present guidelines on the management of extensive disease small cell lung cancer (SCLC) were formulated by the ELCWP in October 2007. They are designed to answer the following nine questions: 1) What is the definition of extensive disease? 2)What are the active drugs? 3) What is the best induction regimen? 4) Is there a role for maintenance chemotherapy? 5) Is there a role for dose-intensive chemotherapy? 6) Is there a role for the use of haemopoietic growth factors and stem cells support? 7) Is there a role for alternating or sequential chemotherapy? 8) Is there a role for biological treatments? 9) Is there a place for second-line chemotherapy

    European Lung Cancer Working Party Clinical Practice Guidelines. Non-Small Cell Lung Cancer: III. Metastatic disease

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    The present guidelines on the management of advanced non-small cell lung cancer (NS CLC) were formulated by the ELCWP in October 2006. They are designed to answer the following twelve questions: 1) What benefits can be expected from chemotherapy and what are the treatment objectives? 2) What are the active chemotherapeutic drugs for which efficacy has been shown? 3) Which are the most effective platinum-based regimens? 4) Which is the indicated dosage of cisplatin? 5) Can carboplatin be substituted for cisplatin? 6) Which is the optimal number of cycles to be administered? 7) Can non-platinum based regimens be substituted for platinum based chemotherapy as first-line treatment? 8) Is there an indication for sequential chemotherapy? 9) What is the efficacy of salvage chemotherapy and which drugs should be used in that indication? 10) What is the place of targeted therapies? 11) What is the place of chemotherapy in the management of a patient with brain metastases? 12) Which specific drugs can be used for the patient with bone metastases
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