Direct determination of geometric alignment parameters for cone-beam scanners
نویسندگان
چکیده
منابع مشابه
Geometric Parameters Estimation and Calibration in Cone-Beam Micro-CT
The quality of Computed Tomography (CT) images crucially depends on the precise knowledge of the scanner geometry. Therefore, it is necessary to estimate and calibrate the misalignments before image acquisition. In this paper, a Two-Piece-Ball (TPB) phantom is used to estimate a set of parameters that describe the geometry of a cone-beam CT system. Only multiple projections of the TPB phantom a...
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چکیده با توسعه شهر نشینی و دخل و تصرف غیر مجاز در حریم رودخانه ها خسارات زیادی به رودخانه و محیط زیست اطراف آن وارده می شود. در حال حاضر بر اساس آئین نامه اصلاح شده بستر و حریم رودخانه ها، حریم کمی رودخانه که بلافاصله پس از بستر قرار می گیرد از 1 تا20 متر از منتهی الیه طرفین بستر رودخانه تعیین، که مقدار دقیق آن در هر بازه از رودخانه مشخص نیست. در کشورهای دیگر روشهای متفاوتی من جمله: درصد ریسک...
15 صفحه اولEffective dose range for dental cone beam computed tomography scanners.
OBJECTIVE To estimate the absorbed organ dose and effective dose for a wide range of cone beam computed tomography scanners, using different exposure protocols and geometries. MATERIALS AND METHODS Two Alderson Radiation Therapy anthropomorphic phantoms were loaded with LiF detectors (TLD-100 and TLD-100 H) which were evenly distributed throughout the head and neck, covering all radiosensitiv...
متن کاملSelf-calibration of geometric and radiometric parameters for cone-beam computed tomography
Thanks to the advances in parallel processing hardware, iterative algorithms for cone beam reconstruction are now available with computation times acceptable for clinical use. At the same time they are able to accomodate more accurately the physical effects underlying the X-Ray imaging process. Many parameters are involved, which need to be precisely calibrated in order to achieve an accurate 3...
متن کاملDirect measurement of human-cone-photoreceptor alignment.
We have developed an imaging reflectometer to measure cone-photoreceptor alignment. One makes measurements by bleaching the cone photopigment and imaging the distribution of light returning from the retina, which is illuminated from a small source imaged in the plane of the eye's pupil. If the source is near the optimal entry pupil position as determined psychophysically, the distribution of li...
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ژورنال
عنوان ژورنال: Physics in Medicine and Biology
سال: 2009
ISSN: 0031-9155,1361-6560
DOI: 10.1088/0031-9155/54/6/016