نتایج جستجو برای: ptv margin
تعداد نتایج: 35795 فیلتر نتایج به سال:
PURPOSE GBM recurrence primarily occurs inside or near the high-dose radiation field of original tumor site requiring greater than 100 Gy to significantly improve local control. We utilize 4π non-coplanar radiotherapy to test the feasibility of planning target volume (PTV) margin expansions or extreme dose escalations without incurring additional radiation toxicities. METHODS 11 GBM patients ...
In prostate radiotherapy, the influence of bladder volume variation on the dose absorbed by the target volume and organs at risk is significant and difficult to predict. In addition, the resolution of a typical medical image is insufficient for visualizing the bladder wall, which makes it more difficult to precisely evaluate the dose to the bladder wall. This simulation study aimed to quantitat...
PURPOSE To assess whether online adaptive radiotherapy for bladder cancer is feasible across multiple Radiation Oncology departments using different imaging, delivery and recording technology. MATERIALS AND METHODS A multi-centre feasibility study of online adaptive radiotherapy, using a choice of three "plan of the day", was conducted at 12 departments. Patients with muscle-invasive bladder ...
By adapting to the actual patient anatomy during treatment, tracked multi-leaf collimator (MLC) treatment deliveries offer an opportunity for margin reduction and healthy tissue sparing. This is assumed to be especially relevant for hypofractionated protocols in which intrafractional motion does not easily average out. In order to confidently deliver tracked treatments with potentially reduced ...
BACKGROUND Reproducibility of different immobilization systems, which may affect set-up errors, remains uncertain. Immobilization systems and their corresponding set-up errors influence the clinical target volume to planning target volume (CTV-PTV) margins and thus may result in undesirable treatment outcomes. This study compared the reproducibility of patient positioning with Hipfix system and...
BACKGROUND The effectiveness of ABC has been traditionally measured as the reduction in internal margin (IM) within the planning target volume (PTV). Not to overestimate the benefit of ABC, the effect of patient movement during treatment also needs to be taken into account. We determined the IM and set-up error with ABC and the effect on physical lung parameters compared to standard margins use...
BACKGROUND An evaluation of the usefulness of target delineation based only on the two extreme phases of a four-dimensional computed tomography (4D CT) scan in lung stereotactic body radiation therapy (SBRT). METHODS Seventeen patients treated with SBRT via 4D CT scans for lung cancer were retrospectively enrolled. Volumetric and geometric analyses were performed for the internal target volum...
AIM The purpose of this study was to examine the usefulness of using Simultaneous Integrated Boost (SIB) radiotherapy for thyroid cancer treatment. BACKGROUND At our hospital a 3D Conformal RadioTherapy (3D-CRT) technique involving photon and electron beams for the treatment of thyroid cancer was often used.(1) High dose to the spinal canal was limiting the total dose of such a treatment. Aft...
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