نتایج جستجو برای: lung motion
تعداد نتایج: 520049 فیلتر نتایج به سال:
This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPET. Techniques for monitoring motion in real time by use of surrogates are reviewed. Treatment planni...
یادگیری فعل و ویژگی های مرتبط با ان همواره یکی از مهم ترین بخش های فراگیری زبان بوده است. افعال حالتی-حرکتی به آن دسته از افعال اطلاق می شودکه حالت وحرکت درآنها ادغام شده است. درزبان انگلیسی مسیر فعل درخود فعل گنجانده می شود (ascend, exit) ولی مسیر فعل درزبان فارسی غالباً توسط حرف اضافه ویا ادات قیدی نشان داده می شود (بیرون رفتن، پایین رفتن). براساس نظرتالمی (1991 ) زبان ها به دو دسته ی ادات محو...
A method is described for the simultaneous measurements of three dimensional shifts of the gravitational center of the body caused by ventilatory and cardiac motions. The measuring system consists fundamentally of three load cells which support an aluminum die-casting platform. Measurement of the shift towards the X axis (front-to-back) was achieved by double integration of the outputs of load ...
Computed tomography (CT) and spirometry are the mainstays of clinical pulmonary assessment. Spirometry is effort dependent and only provides a single global measure that is insensitive for regional disease, and as such, poor for capturing the early onset of lung disease, especially patchy disease such as cystic fibrosis lung disease. CT sensitively measures change in structure associated with a...
Scanned ion beam therapy of lung tumors is severely limited in its clinical applicability by intrafractional organ motion, interference effects between beam and tumor motion (interplay), as well as interfractional anatomic changes. To compensate for dose deterioration caused by intrafractional motion, motion mitigation techniques, such as gating, have been developed. However, optimization of th...
Helical tomotherapy (HT) can potentially be used for lung cancer treatment including stereotactic radiosurgery because of its advanced image guidance and its ability to deliver highly conformal dose distributions. However, previous theoretical and simulation studies reported that the effect of respiratory motion on statically planned tomotherapy treatments may cause substantial differences betw...
Cycle-to-cycle variations in respiratory motion can cause significant geometric and dosimetric errors in the administration of lung cancer radiation therapy. A common limitation of the current strategies for motion management is that they assume a constant, reproducible respiratory cycle. In this work, we investigate the feasibility of using rapid MRI for providing long-term imaging of the thor...
Abstract Purpose Radiation therapy for mesothelioma remains challenging, as normal tissue toxicity limits the amount of radiation that can be safely delivered to pleural surfaces, especially dose contralateral lung. The physical properties proton result in better sparing tissues when treating pleura, both postpneumonectomy setting and lung-intact setting. Compared with photon radiation, there a...
The challenges of lung cancer radiotherapy are intra/inter-fraction tumor/organ anatomy/motion changes and the need to spare surrounding critical structures. Evolving radiotherapy technologies, such as four-dimensional (4D) image-based motion management, daily on-board imaging and adaptive radiotherapy based on volumetric images over the course of radiotherapy, have enabled us to deliver higher...
Introduction: Conventional gradient-echo based magnetic resonance imaging of lung parenchyma suffers from poor signal-to-noise ratios due to low proton density and short T2* caused by susceptibility gradients between airways and tissue. In addition, respiratory and cardiac motions seriously degrade the achievable image quality. Ultra-short echo time (UTE) MRI has recently gained renewed attenti...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید