Influence of anatomical location on CT numbers in cone beam computed tomography

Oliveira, Matheus Lima; Tosoni, Guilherme Monteiro; Lindsey, David H.; Mendoza, Kristopher Anthony; Tetradis, Sotirios; Mallya, Sanjay M.

doi:10.1016/j.oooo.2013.01.021

Cited by 57 publications

(73 citation statements)

References 15 publications

(22 reference statements)

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“…D: Square form basic projection image of the pyramid shape beam instrument (iCAT Classic). The 3D reconstructed image is cylindrically shaped [32,36].The main advantages of dental CBCT are relatively high-resolution acquisition and, compared with conventional CT, lower radiation doses with smaller and less-expensive equipment [11,12,16,17,32,36,[44][45][46][47][48][49][50][51].The next milestone in development was in 2003, when J. Morita Mfg Corporation produced equipment with relatively small volume. In this instrument the patient was already in a seated position (Figure 15 B).…”

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confidence: 99%

“…This became possible because there was no solid surrounding around this single tooth. Consequently, the mass encountered by the X-ray beam does influence both the noise and the grey value accuracy (in HU) [37,47,76]. Of course the image quality is also dependent on the accuracy of the measured grey value in HU.…”

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confidence: 99%

“…With increasing mass and size of material in the FOV, internally, as well as externally (exomass effect), there is an increasing magnitude of X-ray scattering accompanied with increasing noise. These factors also influence the accuracy of the grey values in the reconstructed image [37,39,47,66,68,71,75,76]. Therefore the internal soft tissue in a tooth is not very visible when the tooth is in the head.…”

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confidence: 99%

“…Applying this reduction of the mass and size of material in the FOV, using the reduction of X-ray scattering, it was possible to arrive at a better image quality. This decrease of X-ray scattering causes the reduction of noise in the reconstructed image; therefore it causes an increase in contrast resolution and leads to a better density response of the dental CBCT instrument [13,16,17,29,30,36,37,39,[46][47][48][49][50]53,66,69,70,71]. The advantage of the method outlined about has shown that it was possible to examine of the inner soft tissue content before the destruction of the single tooth structure [63].…”

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confidence: 99%

“…Cone beam computed tomography (CBCT) was originally developed in the early 1980s for angiography [16,17,36,41,53,69], and more than a decade later it was applied to dentomaxillofacial diagnostics. The main advantages of CBCT are relatively high-resolution acquisition and, compared with conventional CT, lower radiation doses with smaller and less expensive equipment [12,16,17,36,[44][45][46][47][48][49]53,69,70,79].As was discussed in Section 5.1, from a technical point of view, the limitation of image quality by dental CBCT technology is dependent on the increased X-ray scatter. This not only increases patient dose but also is a principal contributor to reduced contrast resolution and increased noise in CBCT images [37,46,53,69,71], therefore influencing the density values [13,16,17,29,30,36,37,39,[47][48][49][50]53,66,69,70].…”

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confidence: 99%

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Examination of Grey Value Accuracy and Improvement of Image Quality in Cone Beam Computed Tomography (CBCT)

Plachtovics

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The WARM operation mode represents that the CBCT machine was switched on for at least two hours before the scan but no detector calibration was performed. WARM+C WARM+C scan protocol is consistent with the cone beam computed tomography scan with the complete calibration sequence after the warming-up period. The two-hour warming-up period preceded the calibration process. WUP warming-up period 2D 2 dimensional 3D 3 dimensional iv Galen's principal interest was in human anatomy but, from about 150 BC [2], Roman law had prohibited the dissection of human cadavers. Because of this restriction, Galen performed anatomical dissections on living (vivisection) and dead animals, mostly focusing on pigs and primates [3]. This work was useful because the anatomical structures of these animals usually closely mirror those of humans. Galen clarified the anatomy of the trachea, and was the first to demonstrate that the larynx generates the voice [4,5]. In one experiment, Galen used bellows to inflate the lungs of a dead animal. In his work De motu musculorum, Galen explained the difference between motor and sensory nerves, discussed the concept of muscle tone, and explained the difference between agonists and antagonists [5,6].Andreas Vesalius ( This environment, which lasted from the second century (Galenius) to the sixteenth century (Vesalius), developed a strong desire to have the ability to see inside the human body [7]. Development of medical imagingDuring many centuries the only way to visualize the inside of the human body was through dissection. With technical development, scientists had started to investigate the inside of the human body without its opening. In 1881, Alexander Graham Bell attempted to use magnets and sound waves to discover the location of the bullet that eventually killed U.S.President James A. Garfield [8].After a lengthy period, during scientific experiments with various types of vacuum tube equipment, the discovery of X-rays in 1895, by the Bavarian physicist Conrad Röntgen, represented a major breakthrough (Figure 3 A). When X-rays were finally discovered, they found their way to medical applications within months [9]. B C A 3The original discovery by Röntgen, at the Physical Institute, Julius-Maximilian University, Würzburg, Germany, is recorded to be on 8 November 1895 [9][10][11][12][13][14][15][16][17]. During the discovery, he speculated that a new kind of ray might be responsible for the observation.Since 8 th November was a Friday, instead of relaxing over the weekend, Röntgen took advantage of the time to repeat his experiments. In the following weeks he investigated many properties of the new rays he had temporarily termed 'X-ray'. In fact, he virtually lived in his laboratory during that time. The new X-ray is called the 'Röntgen ray' in many languages [18]. Nearly two weeks after his discovery, he took the very first picture using X-rays of his wife Anna Bertha's hand. When she saw her skeleton she exclaimed 'I have seen my death!' (Figure 3 B and C) [10,18]. Röntgen receive the fir...

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