نتایج جستجو برای: cone beam ct

تعداد نتایج: 274935  

Journal: :Medical physics 2006
Nianming Zuo Dan Xia Yu Zou Tianzi Jiang Xiao-Chuan Pan

Modern computed tomography (CT) scanners use cone-beam configurations for increasing volume coverage, improving x-ray-tube utilization, and yielding isotropic spatial resolution. Recently, there have been significant developments in theory and algorithms for exact image reconstruction from cone-beam projections. In particular, algorithms have been proposed for image reconstruction on chords; an...

Journal: :Physics in medicine and biology 2003
Frédéric Noo Jed Pack Dominic Heuscher

This paper is about helical cone-beam reconstruction using the exact filtered backprojection formula recently suggested by Katsevich (2002a Phys. Med. Biol. 47 2583-97). We investigate how to efficiently and accurately implement Katsevich's formula for direct reconstruction from helical cone-beam data measured in two native geometries. The first geometry is the curved detector geometry of third...

2015
George Puthenpurayil John Tatu Elenjickal Joy Justin Mathew Vinod R. B. Kumar

Cone beam computed tomography (CBCT, also referred to as C-arm computed tomography [CT], cone beam volume CT, or flat panel CT) is a medical imaging technique of X-ray CT where the X-rays are divergent, forming a cone.[1] CBCT systems have been designed for imaging hard tissues of the maxillofacial region. CBCT is capable of providing sub-millimeter resolution in images of high diagnostic quali...

2015

Cone beam computed tomography (CBCT) is a variant of traditional computed tomography (CT) and was first described in the late 1970s. The main difference between the two approaches is the volume of the object that is imaged at one time. In traditional CT, a narrow slice of the patient is imaged with a “fan beam” of X-rays. For an extended volume of the anatomy via CT, the patient must be imaged ...

Fateme Shahedi, Mehdi Jamali Mehdi Momennezhad, Shahrokh Naseri

Introduction: The application of 3D volumetric imaging modalities in treatment planning of radiation therapy can provide more precisely define tumor localization, and computed tomography (CT) is the most common accepted method for treatment planning. Given the lack of a CT scanner stationed in all radiotherapy departments and equipping most of the medical linear accelerators wi...

2009
Emil Y. Sidky Chien-Min Kao

Abstract In practical applications of tomographic imaging, there are often challenges for image reconstruction due to under-sampling and insufficient data. In computed tomography (CT), for example, image reconstruction from few views would enable rapid scanning with a reduced x-ray dose delivered to the patient. Limited-angle problems are also of practical significance in CT. In this work, we d...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی مشهد - دانشکده دندانپزشکی 1393

مقدمه و هدف: از اصولی که در امر آماده سازی و شکل دهی کانال همواره توصیه شده است، حفظ شکل و آناتومی اولیه کانال در عین آماده سازی و پاکسازی آن می باشد.مشخص است که جابه جایی و تغییر شکل کانال حداقل در ساختار دندانی تاثیر گذار خواهد بود. هدف این مطالعه ارزیابی و مقایسه میزان و جهت جابه جایی کانال ریشه در کانال های تایپ ii با استفاده از دو تکنیک آماده سازی متفاوت با کاربرد cbct است. روش کار و مواد...

شریفی, ساناز, ورشوساز, مسعود,

Background: Paranasal sinus disease is one of the most common problems of patients that refer to ENT centers. Adding to clinical examination imaging plays an important role in diagnosis and treatment. Also the imaging of paranasal sinuses is necessary before surgery. Although computed tomography is the modality of choice for these areas, it has some disadvantages which the most important one is...

Journal: :American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics 2016
Alexander Spassov Dragan Pavlovic

4. Radiation protection: cone beam CT for dental and maxillofacial radiology. Evidence based guidelines. 2011. Available at: http:// www.sedentexct.eu/files/guidelines_final.pdf. Accessed December 23, 2015. 5. Halazonetis DJ. Cone-beam computed tomography is not the imaging technique of choice for comprehensive orthodontic assessment [Point/Counterpoint] Am J Orthod Dentofacial Orthop 2012; 141...

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