نتایج جستجو برای: cbct
تعداد نتایج: 4158 فیلتر نتایج به سال:
Cone-beam CT (CBCT) images have recently become an established modality for treatment verification in radiotherapy. However, identification of soft-tissue structures and the calculation of dose distributions based on CBCT images is often obstructed by image artefacts and poor consistency of density calibration. A robust method for voxel-by-voxel enhancement of CBCT images using a priori knowled...
The introduction of cone beam computed tomography (CBCT) devices, changed the way oral and maxillofacial radiology is practiced. CBCT was embraced into the dental settings very rapidly due to its compact size, low cost, low ionizing radiation exposure when compared to medical computed tomography. Alike medical CT, 3 dimensional evaluation of the maxillofacial region with minimal distortion is o...
BACKGROUND To investigate the feasibility of contouring the planning risk organ volume (PRV) for the heart, and to determine the probability of evaluating radiation dose to the heart using kilovoltage-cone beam computed tomography (kV-CBCT) in early-stage non-small-cell lung cancer (NSCLC) patients, who received stereotactic body radiotherapy (SBRT). MATERIALS AND METHODS Seventeen NSCLC pati...
مقدمه و هدف: هدف از این مطالعه ارائه ی تعریفی جامع از ویژگی های cbct برخی ضایعات رادیولوسنت دهانی است تا در تشخیص و درمان بهتر ضایعات کمک کننده باشد. روش اجرای پژوهش: در این مطالعه 40 ضایعه از بیمارانی که دارای نمای رادیولوسنت در تصویر cbct بودند و به یک مرکز خصوصی مراجعه و دارای تشخیص قطعی هیستوپاتولوژی بودند انتخاب شدند. هر یک از ضایعه ها براساس متغیرهایی همچون اکسپنشن باکال و لینگوال،تاثیر ...
There is a growing interest in the use of megavoltage cone-beam computed tomography (MV CBCT) data for radiotherapy treatment planning. To calculate accurate dose distributions, knowledge of the electron density (ED) of the tissues being irradiated is required. In the case of MV CBCT, it is necessary to determine a calibration-relating CT number to ED, utilizing the photon beam produced for MV ...
Image co-registration is used in frameless gamma knife radiosurgery (GKSRS) to assign a stereotactic coordinate system and verify patient setup before irradiation. The accuracy of co-registration with cone beam computed tomography (CBCT) images of a Gamma Knife IconTM (GK Icon) was assessed, and the effects of the region of co-registration (ROC) were studied. CBCT-to-CBCT co-registration is use...
OBJECTIVE The purposes of this study were to determine the accuracy of crown and root length measurements of premolars using cone-beam computed tomography (CBCT) and to generate reference CBCT-based data on incisor, canine, and premolar lengths in patients with malocclusions. METHODS Imaging was performed using a CBCT scanner with a 0.292-mm voxel size and 12-bit grayscale. The CBCT-based len...
Cone-beam CT (CBCT) images are routinely acquired to verify patient position in radiotherapy (RT), but are typically not calibrated in Hounsfield Units (HU) and feature non-uniformity due to X-ray scatter and detector persistence effects. This prevents direct use of CBCT for re-calculation of RT delivered dose. We previously developed a prior-image based correction method to restore HU values a...
The objective of the present study was to assess cone-beam computed tomography (CBCT) as a diagnostic method for determination of gingival thickness (GT) and distance between gingival margin and vestibular (GMBC-V) and interproximal bone crests (GMBC-I). GT and GMBC-V were measured in 348 teeth and GMBC-I was measured in 377 tooth regions of 29 patients with gummy smile. GT was assessed using t...
OBJECTIVES The objective of this study was to compare the sensitivity and reliability of cone-beam computed tomography (CBCT) and intraoral photostimulable phosphor (PSP) imaging plate for diagnosis of endodontic complications. STUDY DESIGN Seventy-two human mandibular teeth were used, including 24 incisors/canines, 24 premolars, and 24 molars. Three images were taken from each group of teeth...
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