Effect of beam energy and filtration on the signal-to-noise ratio of the Dexis intraoral X-ray detector

Kitagawa, Hiromi; Ag, Farman

doi:10.1259/dmfr/26493631

Cited by 16 publications

(13 citation statements)

References 9 publications

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“…Our results corresponded to another authors, as well. Kitagawa and Farman (2004) reported that the Signal-to-Noise Ratio (SNR) of Dexis intraoral radiographic imaging system improved with higher filtration (Kitagawa and Farman, 2004). Wieder and Adams (1981) showed that aluminum filter can improves resolution of chest radiographs.…”

Section: Discussionmentioning

confidence: 99%

Effects of Plastic Wedges on Whole Foot Radiograph in Anteroposterior and Oblique Positions

Lorlorm¹,

Choiprasert²,

Tungjai³

et al. 2017

American Journal of Applied Sciences

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Abstract:The whole foot radiography may be taken twice with different exposure parameters. It produces two images in two radiation exposures; one is the metatarsal view of the phalange and the other is a tarsal view. The aim of this study was to study the effects of plastic wedges on whole foot radiography with one radiation exposure. The plastic wedge was developed from plastic wood. Whole foot phantom radiographic imaging was created in anteroposterior and oblique positions with and without plastic wedges mounted on the collimator of an X-ray machine. A radiation imaging plate was used as a transmitted-radiation receptor. The radiation exposure parameter was 54 kilo-voltage at 100 milliamperes for 0.02 sec. The results showed that the resolution of whole foot phantom radiographic imaging in both anteroposterior and oblique positions with plastic wedge mounted on a collimator of an X-ray machine was better than without plastic wedge mounted on collimator. Percentage of Coefficient Variance (%CV) of pixel value on radiographic imaging with plastic wedge mounted on collimator was less than without plastic wedge mounted on collimator. This finding suggests that plastic wedges can help improve image quality of whole foot radiography with one radiation exposure.

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Section: Discussionmentioning

confidence: 99%

Effects of Plastic Wedges on Whole Foot Radiograph in Anteroposterior and Oblique Positions

Lorlorm¹,

Choiprasert²,

Tungjai³

et al. 2017

American Journal of Applied Sciences

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“…Thus, the GC was Al with 1.5 mm in thickness, which differs from other studies. 1,6,7,13,14 Mauriello et al 6 evaluated the effects on image contrast and on exposure dose caused by the increased thickness of the Al filter. In their results was Figure 3 Optical density curves of all filters in the exposure time of 0.32 s and regression analysis of the standard filter including a prediction limit of 5%.…”

Section: Discussionmentioning

confidence: 99%

Alternative X-ray filters for an intra-oral digital radiographic system

Stecke

Cruz²,

Almeida³

et al. 2012

Dentomaxillofacial Radiology

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Objective: The aim of this study was to evaluate the effect of the modulation of the radiation spectrum with the use of alternative X-ray filters in the quality of intra-oral digital images from storage phosphor plates. Methods: The radiographic exposures were performed in a GE 1000 X-ray machine (General Electric Co., Milwaukee, WI), operating at 65 kVp, 10 mA, 40 cm focus receptor distance using three different exposure times: 0.05 s, 0.16 s and 0.35 s. The control filter (GC) was 100% aluminium (Al) with a thickness of 1.5 mm. The tested filters were: G1, 97% Al and 3% copper (Cu) with 1.47 mm thickness; G2, 96% Al and 4% Cu with 1.53 mm thickness; G3, 95% Al and 5% zinc (Zn) with 1.56 mm thickness; G4, 98% Al and 2% Zn with 1.5 mm thickness; and G5, 95% Cu and 5% Zn with 1.6 mm thickness. For formation of the image, a 12-step Al wedge (each step with increments of 1 mm in thickness) was radiographed 10 times. Pixel values measured in digital images were converted into optical density (OD). Results: All replicates showed OD with high reproducibility (r . 0.95) for all exposure times and tested filters. In comparison between filters, statistically significant differences in density (p , 0.05) were observed. The OD curve of the G5 filter in all exposure times and G3 filter in an exposure time of 0.05 s showed changes in shape (p , 0.05). Conclusions: Excluding the G5 filter, all others tested filters can be used as a substitute for GC without losses in image quality.

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“…This is why spatial resolution estimates based on picture element size are not able to consistently provide useful information regarding the actual spatial resolution of an imaging system. However, image processing is not the only cause of degradation of image quality; pixel cross-talk, quantum noise, dark current and unequal pixel efficiencies should also be [19][20][21] Within the study, only tests on synthetic images with Gaussian noise were conducted. However, there are numerous types of noise including fixed pattern noise, the type found on digital images acquired by CCD sensors where particular pixels are responsible for creating intensities brighter than the general background noise; and salt and pepper noise, which is typically found in images acquired by sensors containing pixels that have malfunctioned.…”

Section: Discussionmentioning

confidence: 99%

The modulation transfer function and signal-to-noise ratio of different digital filters: a technical approach

Brüllmann¹,

dʼHoedt²

2011

Dentomaxillofacial Radiology

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Objectives: The aim of this study was to illustrate the influence of digital filters on the signal-to-noise ratio (SNR) and modulation transfer function (MTF) of digital images. The article will address image pre-processing that may be beneficial for the production of clinically useful digital radiographs with lower radiation dose. Methods: Three filters, an arithmetic mean filter, a median filter and a Gaussian filter (standard deviation (SD) 5 0.4), with kernel sizes of 3 6 3 pixels and 5 6 5 pixels were tested. Synthetic images with exactly increasing amounts of Gaussian noise were created to gather linear regression of SNR before and after application of digital filters. Artificial stripe patterns with defined amounts of line pairs per millimetre were used to calculate MTF before and after the application of the digital filters. Results: The Gaussian filter with a 5 6 5 kernel size caused the highest noise suppression (SNR increased from 2.22, measured in the synthetic image, to 11.31 in the filtered image). The smallest noise reduction was found with the 3 6 3 median filter. The application of the median filters resulted in no changes in MTF at the different resolutions but did result in the deletion of smaller structures. The 5 6 5 Gaussian filter and the 5 6 5 arithmetic mean filter showed the strongest changes of MTF. Conclusions: The application of digital filters can improve the SNR of a digital sensor; however, MTF can be adversely affected. As such, imaging systems should not be judged solely on their quoted spatial resolutions because pre-processing may influence image quality.

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Effect of beam energy and filtration on the signal-to-noise ratio of the Dexis intraoral X-ray detector

Abstract: For the Dexis intraoral radiographic imaging system, estimated SNR improved both with higher filtration and with lower kVp. The Dexis detector was capable of generating acceptable images of the step wedge at a wide range of kVp settings.

Cited by 16 publications

References 9 publications

Effects of Plastic Wedges on Whole Foot Radiograph in Anteroposterior and Oblique Positions

Effects of Plastic Wedges on Whole Foot Radiograph in Anteroposterior and Oblique Positions

Alternative X-ray filters for an intra-oral digital radiographic system

The modulation transfer function and signal-to-noise ratio of different digital filters: a technical approach

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