543 research outputs found
Using Shipping Containers to Provide Temporary Housing in Post-disaster Recovery: Social Case Studies
AbstractHousing that makes use of the ubiquitous general purpose shipping container is becoming more commonly seen as a useful way of reusing the empty vessels as valuable accommodation. In particular, the application of shipping container temporary housing is suited to post-disaster situations, design examples of which can be found in the literature. However, ensuring the success of implementing such projects in a post-disaster setting requires investigation into the social considerations of temporary housing. This research takes a qualitative approach, focusing particularly on case studies of temporary housing experiences following the Hurricane Katrina in 2005, the Christchurch Earthquake in 2011 and a field study of 2009 Black Saturday bushfire-affected communities in Victoria, Australia. Key social factors found to be significant to the success of shipping container temporary housing projects relate to flexibility in ownership, reuse and siting arrangement, in addition to robust pre-disaster planning by authorities, taking into account the varying characteristics of different types of disasters
SHOULD PATIENT SETUP IN LUNG CANCER BE BASED ON THE PRIMARY TUMOR? AN ANALYSIS OF TUMOR COVERAGE AND NORMAL TISSUE DOSE USING REPEATED POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY IMAGING
PURPOSE: Evaluation of the dose distribution for lung cancer patients using a patient set-up procedure based on the bony anatomy or the primary tumor. METHODS AND MATERIALS: For 39 (non-)small cell lung cancer patients the planning FDG-PET/CT scan was registered to a repeated FDG-PET/CT scan made in the second week of treatment. Two patient set-up methods were analyzed: bony anatomy or primary tumor set-up. The original treatment plan was copied to the repeated scan, and target and normal tissue structures were delineated. Dose distributions were analyzed using dose-volume histograms for the primary tumor, lymph nodes, lungs and spinal cord. RESULTS: One patient showed decreased dose coverage of the primary tumor due to progressive disease and required re-planning to achieve adequate coverage. For the other patients, the minimum dose to the primary tumor did not significantly deviate from the planned dose: β0.2Β±1.7% (p=0.71) and β0.1Β±1.7% (p=0.85) for the bony anatomy and primary tumor set-up, respectively. For patients (N=31) with nodal involvement, 10% showed a decrease in minimum dose larger than 5% for the bony-anatomy set-up and 13% for the primary tumor based set-up. Mean lung dose exceeded the maximum allowed 20 Gy in 21% of the patients for the bony-anatomy and in 13% for the primary tumor set-up, whereas for the spinal cord this occurred in 10% and 13% of the patients, respectively. CONCLUSIONS: In 10% and 13% of patients with nodal involvement, set-up based on bony anatomy or primary tumor, respectively, lead to important dose deviations in nodal target volumes. Overdosage of critical structures occurred in 10-20% of the patients. In case of progressive disease, repeated imaging revealed underdosage of the primary tumor. Development of practical ways for set-up procedures based on repeated high-quality imaging of all tumor sites during radiotherapy should therefore be an important research focus
OC-0253: CT characteristics allow to identify individual and regional susceptibility for radiation-induced lung damage
PET-based dose painting in non-small cell lung cancer: Comparing uniform dose escalation with boosting hypoxic and metabolically active sub-volumes.
BACKGROUND AND PURPOSE: We compared two imaging biomarkers for dose-escalation in patients with advanced non-small cell lung cancer (NSCLC). Treatment plans boosting metabolically active sub-volumes defined by FDG-PET or hypoxic sub-volumes defined by HX4-PET were compared with boosting the entire tumour.MATERIALS AND METHODS: Ten NSCLC patients underwent FDG- and HX4-PET/CT scans prior to radiotherapy. Three isotoxic dose-escalation plans were compared per patient: plan A, boosting the primary tumour (PTVprim); plan B, boosting sub-volume with FDG >50% SUVmax (PTVFDG); plan C, boosting..
Assessment of accuracy of non-rigid registration algorithms for follow-up treatment NSCLC imaging (Conference Abstract)
Image quality evaluation of a new high-performance ring-gantry cone-beam computed tomography imager
Objective. Newer cone-beam computed tomography (CBCT) imaging systems offer reconstruction algorithms including metal artifact reduction (MAR) and extended field-of-view (eFoV) techniques to improve image quality. In this study a new CBCT imager, the new Varian HyperSight CBCT, is compared to fan-beam CT and two CBCT imagers installed in a ring-gantry and C-arm linear accelerator, respectively. Approach. The image quality was assessed for HyperSight CBCT which uses new hardware, including a large-size flat panel detector, and improved image reconstruction algorithms. The decrease of metal artifacts was quantified (structural similarity index measure (SSIM) and root-mean-squared error (RMSE)) when applying MAR reconstruction and iterative reconstruction for a dental and spine region using a head-and-neck phantom. The geometry and CT number accuracy of the eFoV reconstruction was evaluated outside the standard field-of-view (sFoV) on a large 3D-printed chest phantom. Phantom size dependency of CT numbers was evaluated on three cylindrical phantoms of increasing diameter. Signal-to-noise and contrast-to-noise were quantified on an abdominal phantom. Main results. In phantoms with streak artifacts, MAR showed comparable results for HyperSight CBCT and CT, with MAR increasing the SSIM (0.97-0.99) and decreasing the RMSE (62-55 HU) compared to iterative reconstruction without MAR. In addition, HyperSight CBCT showed better geometrical accuracy in the eFoV than CT (Jaccard Conformity Index increase of 0.02-0.03). However, the CT number accuracy outside the sFoV was lower than for CT. The maximum CT number variation between different phantom sizes was lower for the HyperSight CBCT imager (βΌ100 HU) compared to the two other CBCT imagers (βΌ200 HU), but not fully comparable to CT (βΌ50 HU). Significance. This study demonstrated the imaging performance of the new HyperSight CBCT imager and the potential of applying this CBCT system in more advanced scenarios by comparing the quality against fan-beam CT.</p
Image quality evaluation of a new high-performance ring-gantry cone-beam computed tomography imager
Objective. Newer cone-beam computed tomography (CBCT) imaging systems offer reconstruction algorithms including metal artifact reduction (MAR) and extended field-of-view (eFoV) techniques to improve image quality. In this study a new CBCT imager, the new Varian HyperSight CBCT, is compared to fan-beam CT and two CBCT imagers installed in a ring-gantry and C-arm linear accelerator, respectively. Approach. The image quality was assessed for HyperSight CBCT which uses new hardware, including a large-size flat panel detector, and improved image reconstruction algorithms. The decrease of metal artifacts was quantified (structural similarity index measure (SSIM) and root-mean-squared error (RMSE)) when applying MAR reconstruction and iterative reconstruction for a dental and spine region using a head-and-neck phantom. The geometry and CT number accuracy of the eFoV reconstruction was evaluated outside the standard field-of-view (sFoV) on a large 3D-printed chest phantom. Phantom size dependency of CT numbers was evaluated on three cylindrical phantoms of increasing diameter. Signal-to-noise and contrast-to-noise were quantified on an abdominal phantom. Main results. In phantoms with streak artifacts, MAR showed comparable results for HyperSight CBCT and CT, with MAR increasing the SSIM (0.97-0.99) and decreasing the RMSE (62-55 HU) compared to iterative reconstruction without MAR. In addition, HyperSight CBCT showed better geometrical accuracy in the eFoV than CT (Jaccard Conformity Index increase of 0.02-0.03). However, the CT number accuracy outside the sFoV was lower than for CT. The maximum CT number variation between different phantom sizes was lower for the HyperSight CBCT imager (βΌ100 HU) compared to the two other CBCT imagers (βΌ200 HU), but not fully comparable to CT (βΌ50 HU). Significance. This study demonstrated the imaging performance of the new HyperSight CBCT imager and the potential of applying this CBCT system in more advanced scenarios by comparing the quality against fan-beam CT.</p
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