نتایج جستجو برای: mathematical head phantom
تعداد نتایج: 394361 فیلتر نتایج به سال:
The Elekta Synergy is a radiotherapy treatment machine with integrated kilovoltage (kV) X-ray imaging system capable of producing cone beam CT (CBCT) images of the patient in the treatment position. The aim of this study is to assess the additional imaging dose. Cone beam CT dose index (CBDI) is introduced and measured inside standard CTDI phantoms for several sites (head: 100 kV, 38 mAs, lung:...
The main purpose of this work was to quantify patient organ doses from the two kilovoltage cone beam computed tomography (CBCT) systems currently available on medical linear accelerators, namely the X-ray Volumetric Imager (XVI, Elekta Oncology Systems) and the On-Board Imager (OBI, Varian Medical Systems). Organ dose measurements were performed using a fiber-optic coupled (FOC) dosimetry syste...
A comprehensive end-to-end test for head and neck IMRT treatments was developed using a custom phantom designed to utilize multiple dosimetry devices. Initial end-to-end test and custom H&N phantom were designed to yield maximum information in anatomical regions significant to H&N plans with respect to: (i) geometric accuracy, (ii) dosimetric accuracy, and (iii) treatment reproducibility. The p...
Correspondence to: Fábio Luiz Ferreira Scannavino Avenida 23, 0126 Centro 14781-343 Barretos, SP, Brasil Phone: +55-17-3322-1360 E-mail: [email protected] Received for publication: January 14, 2010 Accepted: June 16, 2010 Abstract Aim: The purpose of this study was to compare the effectiveness of a high-volume evacuation and a conventional intraoral suction system and aspirating tips for c...
Introduction: Nasopharyngeal carcinoma is one of the most common malignancies in the head and neck region and radiotherapy is its treatment of choice. In spite of the fact that it is widely used, due to the presence of many sensitive organs or tissues in this region, patients may suffer from a wide range of side effects. One such sensitive tissue is the spinal cord. If the absorbed dose to spin...
introduction: in patients with thyroid carcinoma, radiation absorbed doses of the thyroid and surrounding tissues is important to weigh risk and benefit considerations. in nuclear medicine, the accuracy of absorbed dose of internally distributed radionuclides is estimated by different methods such as mird and direct method using tld. the aim of this study is using tld and a phantom to determine...
The purpose of this study was to assess quantitatively elongation of mobile targets in cone-beam CT (CBCT) imaging by measurement and modeling. A mathematical model was derived that predicts the measured lengths of mobile targets and its dependence on target size and motion patterns in CBCT imaging. Three tissue-equivalent targets of differing sizes were inserted in an artificial thorax phantom...
there has been a gradual shift of focus from the study of rule systems, which have increasingly been regarded as impoverished, … to the study of systems of principles, which appear to occupy a much more central position in determining the character and variety of possible human languages. there is a set of absolute universals, notions and principles existing in ug which do not vary from one ...
Computed Tomography (CT) scans promote a higher dose deposition than conventional radiology exams. These tests contribute significantly to the increase in patient and collective dose, being public health concern worldwide.
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