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... 3S -- 79 -- 1 D -- 14S -- 19S -- CONTENTS -- Operational Principles for Cone-Beam Computed Tomography ... ... Practical Applications of Cone-Beam Computed Tomography in Orthodontics -- J.K. Mah, J. C. ... ... Choo -- The authors provide a practical guide for applying cone-beam computed tomography in orthodontics ... ... -- The authors describe the benefits of using cone-beam computed tomography to complement plain film ... ... The Role of Cone-Beam Computed Tomography in the Planning and Placement of Implants -- P. ...
JADA, ISSN 0002-8177 Volume 141 10 Supplement October 2010
24 stran : ilustrace ; 28 cm
- Konspekt
- Stomatologie
- NLK Obory
- zubní lékařství
- radiologie, nukleární medicína a zobrazovací metody
- NLK Publikační typ
- brožury
... Cone beam computed tomography in clinical practice -- Basic principles of cone beam computed tomography ... ... -- Anatomic structures in cone beam images -- Airway analysis -- Dental findings -- Impacted teeth - ...
2nd ed. vii, 399 s. : il. ; 29 cm
- MeSH
- abnormality ústního a čelistního systému diagnóza klasifikace radiografie MeSH
- počítačová tomografie s kuželovým svazkem metody využití MeSH
- stomatologické nemoci diagnóza klasifikace radiografie MeSH
- ústní a čelistní systém radiografie MeSH
- Publikační typ
- atlasy MeSH
- Konspekt
- Stomatologie
- NLK Obory
- zubní lékařství
Přehledové sdělení se zabývá porovnáním dvou zobrazovacích modalit - klinickým CT a cone-beam CT. Tyto modality jsou zde popsány z hlediska způsobu náběru dat, rekonstrukce obrazu a kvality obrazu společně se souvisejícími artefakty. Součástí sdělení je i detailní popis detekčních mechanismů.
The article deals with a comparison and assessment of imgaing performed by the clinical CT and cone-beam CT. These imaging modalities are desribed, mainly as reagrds image acquisition, image reconstruction, and image quality with related artifacts. A comprehensive description of detection mechanisms is a part of the article.
The number of L cones in the retina normally exceeds that of the M cones. Because normal color vision does not depend on the ratio of L- and M-photoreceptors, their signals must undergo an alteration in gain before being analyzed in the cortex. Previous studies have shown that this gain must take place before the cortex, but after the bipolar/amacrine cell layer of the retina. The aim of this study was to obtain topographical information about L- and M-cone activity at the ganglion cell layer using multifocal pattern electroretinography (mfPERG). A standard (black and white) stimulus was used, as well as stimuli modulating only the long wavelength-sensitive (L) or only the middle wavelength-sensitive (M) cones. The L:M ratio was calculated from the amplitude of the L-cone isolating mfPERG to that of the M-cone isolating mfPERG of 10 trichromats. Both the positive and negative components of the waveform were analyzed. Additional recordings of single cone modulated mfERGs were obtained from nine of the 10 subjects. We also recorded from one protanope and one deuteranope. The L:M cone amplitude ratios for both deflections of the mfPERG in the trichromats were around unity (medians 1.18 and 1.16, respectively) for the central 8 degrees of retina. In the peripheral retina between 12.8 degrees and 26 degrees , this ratio increased to 1.42 for the positive component, and 1.37 for the negative component. The median L:M cone amplitude ratios for the mfPERG were higher and ranged between 1.00-2.78 in the central 8 degrees and 1.29-2.78 in the periphery. The results indicate that a major gain adjustment of the retinal signals takes place at the ganglion cell level, and that the ratio is higher at eccentric locations than in the central retinal area.
- MeSH
- barva MeSH
- čípky retiny parazitologie MeSH
- citlivost na kontrast fyziologie MeSH
- dospělí MeSH
- elektroretinografie MeSH
- lidé MeSH
- poruchy barevného vidění patofyziologie MeSH
- psychofyzika MeSH
- reakční čas MeSH
- senzorické prahy fyziologie MeSH
- světelná stimulace MeSH
- testy barvocitu MeSH
- vnímání barev MeSH
- zraková pole fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
Cone-beam CT (CBCT) je poměrně nová zobrazovací technologie, která umožňuje 3D zobrazení rentgen-kontrastních součástí orofaciálního systému. Principem zařízení je získání velkého množství 2D rentgenových snímků, které jsou pomocí softwaru počítačově zpracovány do 3D obrazu. Při nízké dávce a dostačujícím prostorovém rozlišení poskytuje dostatek údajů pro diagnostiku, plánování a kontrolu terapie. Nejčastější aplikace v endodoncii zahrnují přesné trojrozměrné zobrazení kořenů a kanálků zubů, periapikálních patologických procesů, vnitřní a vnější resorpci kořene a detekci jeho fraktur. CBCT má také nezastupitelnou roli v monitorování úspěšnosti léčby. Ve srovnání s klasickým CT má CBCT vyšší přesnost, větší rozlišení, kratší čas skenování a redukovanou dávku radiačního záření. Ve srovnání s konvečním intraorálním RTG má CBCT schopnost eliminovat superpozici okolních struktur a zvětšení způsobené rozdílným úhlem dopadu RTG paprsku nebo různou vzdáleností vyšetřovaného objektu od RTG snímku a senzoru. Poskytne tak klinicky přesné a relevantní informace. Stinná stránka zahrnuje zatím limitovanou dostupnost a významnou počáteční investici.
Cone-beam CT is a new technology, able to provide a 3D imaging of parts of the orofacial system. In principle, the device is able to obtain a large amount of 2D X-ray images, which are transferred to 3D picture by computer. With a limited radiation dose and substantial space resolution, it offers enough data for diagnosis, treatment planning and recall. The most often applications in endodontics include precise 3D imaging of roots and root canals, periapical pathological processes, internal and external resorption and detection of root fractures. Moreover, CBCT plays an important role in monitoring of treatment success. When compared to classical CT, the CBCT offers increased preciseness, higher resolution, shorter imaging time and reduced radiation dose. When compared to conventional intraoral X-ray, the CBCT has an ability to eliminate superposition of surrounding structures and magnification, caused by different angle of beam and different distance of examined subject from X-ray image to sensor. It offers clinically clear and relevant informations. The negatives include limited availability and significant price.
- Klíčová slova
- rentgen (RTG),
- MeSH
- diagnostické zobrazování metody přístrojové vybavení trendy MeSH
- endodoncie trendy MeSH
- financování organizované MeSH
- lidé MeSH
- počítačová tomografie s kuželovým svazkem přístrojové vybavení trendy využití MeSH
- zobrazování trojrozměrné přístrojové vybavení trendy využití MeSH
- Check Tag
- lidé MeSH
Cryptochromes are a ubiquitous group of blue-light absorbing flavoproteins that in the mammalian retina have an important role in the circadian clock. In birds, cryptochrome 1a (Cry1a), localized in the UV/violet-sensitive S1 cone photoreceptors, is proposed to be the retinal receptor molecule of the light-dependent magnetic compass. The retinal localization of mammalian Cry1, homologue to avian Cry1a, is unknown, and it is open whether mammalian Cry1 is also involved in magnetic field sensing. To constrain the possible role of retinal Cry1, we immunohistochemically analysed 90 mammalian species across 48 families in 16 orders, using an antiserum against the Cry1 C-terminus that in birds labels only the photo-activated conformation. In the Carnivora families Canidae, Mustelidae and Ursidae, and in some Primates, Cry1 was consistently labeled in the outer segment of the shortwave-sensitive S1 cones. This finding would be compatible with a magnetoreceptive function of Cry1 in these taxa. In all other taxa, Cry1 was not detected by the antiserum that likely also in mammals labels the photo-activated conformation, although Western blots showed Cry1 in mouse retinal cell nuclei. We speculate that in the mouse and the other negative-tested mammals Cry1 is involved in circadian functions as a non-light-responsive protein.
- MeSH
- antisérum chemie MeSH
- Canidae fyziologie MeSH
- čípky retiny - opsiny genetika MeSH
- čípky retiny fyziologie účinky záření ultrastruktura MeSH
- cirkadiánní rytmus fyziologie účinky záření MeSH
- exprese genu MeSH
- fylogeneze * MeSH
- Hominidae fyziologie MeSH
- imunohistochemie MeSH
- konformace proteinů MeSH
- kryptochromy chemie genetika MeSH
- magnetické pole MeSH
- medvědovití fyziologie MeSH
- Mustelidae fyziologie MeSH
- proteinové domény MeSH
- ptáci fyziologie MeSH
- savci klasifikace fyziologie MeSH
- světlo MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PURPOSE: Anastomosis between posterior superior alveolar artery and infraorbital artery can go through bony canal in the lateral wall of the maxilla. This artery is called alveolar antral artery. It can complicate lateral sinus lift procedure by bleeding and hemosinus formation or bone graft wash out. The artery can also go in soft tissues where is not visible on cone beam computed tomography. In previous studies, the relation of this artery to sinus floor or alveolar process was measured. These structures are highly unstable during lifetime and after tooth loss. The aim of this study is to study presence and relations of bony canal in the lateral maxillary wall, to characterize the group of patients which is more likely to have bone canal in the lateral maxilla. The aim and the novelty of this study is the describing of the relationship of the bony canal to the more stable structure of hard palate and describing the relation of presence of bony canal on width of maxillary sinus, and to facilitate the prediction of presence of the alveolar antral artery. MATERIALS: The cone beam computed tomography scans of the patients (251 in number) of the university hospital were examined for presence of alveolar antral artery (148 was fulfilled inclusion criteria), patient were characterized by gender, age, and sinus type (wide, average, narrow). The diameter of the bony canal and its relation to the level of sinus floor and hard palate were measured. RESULTS: The cone beam computed tomography scans of 148 patients, out of it 55 man (37,2%) and 93 women (62,8%). Bony canal containing alveolar anastomosis was found in 69 cases (57,0%). Presence of the bony canal in the lateral wall of maxillae showed statistical probability depending on age with p = 0, 064 according to Mann-Whitney test. The older patients have more likely the bony canal. The presence of the alveolar antral artery was found more likely in the wide sinuses. The hard palate level can serve as a prediction point of alveolar antral artery only in first molar and second premolar region. In accordance with previous studies the width of bony canal is significantly higher in group of man (p = 0, 015). There was found a correlation between smaller distance of bony canal from sinus floor in the presence of teeth (p = 0, 067). After tooth loss the distance between sinus floor and bony canal increases, but the distance of bony canal to hard palate level stays constant. This can be explained hypothetically so that periodontal ligaments and root surface acts as a barrier for sinus pneumatization. CONCLUSION: Lateral sinus lifting in some cases can be unenviable, the knowledge about alveolar antral artery anatomy can reduce the risk of arterial bleeding. The cone-beam computed tomography is a routine examination prior to augmentation surgery and therefore the data obtained from it has an impact on clinical practice.
- MeSH
- arterie diagnostické zobrazování MeSH
- augmentace dna čelistní dutiny * MeSH
- lidé MeSH
- počítačová tomografie s kuželovým svazkem metody MeSH
- processus alveolaris diagnostické zobrazování MeSH
- ztráta zubů * MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
3D Multislice and Cone-beam computed tomography (CBCT) in forensic odontology has been shown to be useful not only in terms of one or a few of dead bodies but also in multiple fatality incidents. 3D Multislice and Cone-beam computed tomography and digital radiography were demonstrated in a forensic examination form. 3D images of the skull and teeth were analysed and validated for long ante mortem/post mortem intervals. The image acquisition was instantaneous; the images were able to be optically enlarged, measured, superimposed and compared prima vista or using special software and exported as a file. Digital radiology and computer tomography has been shown to be important both in common criminalistics practices and in multiple fatality incidents. Our study demonstrated that CBCT imaging offers less image artifacts, low image reconstruction times, mobility of the unit and considerably lower equipment cost.
U pacientů po kochleární implantaci je velmi důležitá informace o pozici svazku elektrod implantátu, a to jak pro chirurga, tak i rehabilitační tým. Cone-beam CT (CBCT) je speciálním typem počítačové tomografie (CT) umožňující s nižší radiační dávkou dosáhnout lepšího zobrazení na malé ploše kochley. Cílem sdělení je informovat odbornou veřejnost o zavedení této zobrazovací metody. V souboru Kliniky otorinolaryngologie a chirurgie hlavy a krku FN Hradec Králové bylo CBCT provedeno u 31 kochleárních implantací u 30 uživatelů kochleárních implantátů všech výrobců dostupných v České republice. Hodnoceny byly vybrané parametry, jejichž výsledky jsou diskutovány. CBCT je již běžně používáno na zahraničních implantačních pracovištích a jeho zavedení v České republice je logickým krokem ke zlepšení péče implantačních center v ČR. Pro správný proces vyšetření je důležitá týmová spolupráce lékařů ORL, vyšetřujícího rentgenového laboranta, interpretujícího rentgenologa a rehabilitačního týmu. V současné době je CBCT prováděno pooperačně ke kontrole hloubky zavedení svazku elektrod před zapojením zvukového (řečového) procesoru kochleárního implantátu. Optimálním cílem v budoucnu je využití CBCT na operačním sále, pomocí kterého lze ověřit polohu elektrodového svazku již během operačního výkonu a provést její případnou korekci před uzavřením kochley a operačního pole.
The information about the position of the implant after cochlear implantation is very important for the surgeon and the entire rehabilitation team. Cone-beam CT (CBCT) is a special type of computed tomography (CT), which provides better imaging with a lower radiation dose on a small area of the cochlea. The aim of the paper is to inform the professional public about the introduction of this imaging method in Czechia. In the ORL Dept. University Hospital Hradec Králové, CBCT has been performed on 31 devices in 30 users of cochlear implant of all three CI manufacturers available in the Czech Republic. Selected parameters were evaluated and their results are discussed. CBCT is a standard at foreign implant centres and its introduction in the Czech Republic is a logical step towards improving the care of implant centres. The teamwork of ENT doctors, examining stomatologist, interpreting radiologist and rehabilitation team is important for a correct examination process. Optimum of the imaging in the future will be perioperative CBCT in the operating room, which can only be used to verify the position of the electrode array in all patients immediately after insertion and eventually to reposition it.
PURPOSE: To investigate the setup margins in prostate cancer treatment without using daily online repositioning methods. METHODS: We analysed the data from patients treated with curative-intend radiotherapy. Each patient underwent a series of pretreatment online localizations during daily setup using conebeam CT. The skin-prostate shifts and bone-prostate shifts were recorded in anteroposterior (AP), craniocaudal (CC), and laterolateral (LL)direction. The safety margins based on van Herk equation (2.5Σ+0.7σ) were calculated and the correlations between margins and various patient characteristics and prostate locations were investigated. RESULTS: A total of 307 patients were included, representing 11,726 localisations resulting in 70,356 shifts. The man skin-prostate setup inaccuracy was 0.8 ± 5.4mm in AP, 1.3 ± 4.8mm for CC, and 0.1 ± 5.6mm in LL direction. The man bone-prostate setup inaccuracy was 0.4 ± 3.3mm in AP, 0.1 ± 2.5mm for CC, and 0.1 ± 1.4mm in LL direction. According to van Herk equation, clinical target volume (CTV)-planning target volume (PTV) margins of 11.4, 10.6, and 11.8 mm (AP, CC, and LL, respectively) would be required for setup using skin markers and margins of 7.0, 4.7, and 2.1mm would be necessary for setup using bone structures. The average rectal area < 11cm(2) and volume of bladder > 300 cm(3) were associated with smaller CTV-PTV margins for setup using bone structures. The largest margins (15.8 mm in LL direction) were needed in patients with body mass index (BMI) > 35 using skin markers. CONCLUSIONS: Our results confirm that the commonly used CTV-PTV margins are inadequate.
- MeSH
- lidé MeSH
- nádory prostaty radiografie radioterapie MeSH
- počítačová tomografie s kuželovým svazkem * MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH