Imaging Characteristics of an Amorphous Silicon Flat-Panel Detector for Digital Chest Radiography

Floyd, Carey E.; Warp, Richard J.; Dobbins, James T.; Chotas, H.; Baydush, Alan H.; Vargas-Voracek, Rene; Ravin, Carl E.

doi:10.1148/radiology.218.3.r01fe45683

Cited by 119 publications

(68 citation statements)

References 9 publications

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“…( 13 – 15 ) The RMTF is the ratio of the MTF at a specific frequency to the MTF at the lowest frequency of a line‐pair template. In the present study, the 0.6 lp/mm line pair, the lowest frequency in the template, was used as the normalization—that is,

f_{1} = 0.6

lp/mm.…”

Section: Methodsmentioning

confidence: 99%

“…To quantify the linearity and repeatability of the X‐ray output, unit exposure (mR) per unit milliampere second (that is, mR/mAs) was calculated for a fixed milliampere second at six different kilovoltage photon settings (40, 60, 80, 100, 120, and 150 kVp) (13) . In the present study, 16 mAs was used with four different milliampere and millisecond combinations (that is,

80 mA \times 200 ms, 100 mA \times 160 ms, 160 mA \times 100 ms, and 200 mA \times 80 ms

).…”

Section: Methodsmentioning

confidence: 99%

“…The repeatability of the X‐ray output was calculated (13) using

% Repeatability = \frac{(\frac{M a x i m u m m R - M i n i m u m m R}{2})}{A v e r a g e m R} \times 100 %^{,}

…”

Section: Methodsmentioning

confidence: 99%

“…“Repeatability” checks the stability of the pixel reading when no object is under exposure (13) . To avoid saturation of the flat panel detectors in the present study, uniformity and repeatability were tested at 63 kVp and 80 kVp with 63 mA and 63 ms, instead of the higher kilovoltage and milliampere settings used in the daily clinical setting.…”

Section: Methodsmentioning

confidence: 99%

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Clinical assessment and characterization of a dual‐tube kilovoltage X‐ray localization system in the radiotherapy treatment room

Lee

Jin

Guan

et al. 2008

J Applied Clin Med Phys

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Although flat‐panel kilovoltage X‐ray imaging devices have been well tested for clinical use in diagnostic radiology, their use as a part of an image‐guided radiation therapy (IGRT) system in a treatment room is new and requires systematic assessment.We used the Novalis IGRT system (BrainLAB, Feldkirchen, Germany) for the present study. The system consists of two floor‐mounted kilovoltage X‐ray tubes projecting obliquely onto two flat‐panel detectors mounted on the ceiling. The system can automatically fuse two‐dimensional localization images with three‐dimensional simulation computed tomography images to provide positioning guidance. We evaluated these system parameters: Overall performance of the IGRT system, including isocenter correlation between the IGRT system and the linear accelerator (LINAC)Image quality of the systemExposure received by patients for a pair of imagesLinearity, uniformity, and repeatability of the system The Novalis system uses a daily isocenter calibration procedure to ensure consistency of isocenters between the IGRT and the LINAC systems. The localization accuracy was about 1 mm. We measured the relative modulation transfer function (RMTF) to quantify the spatial resolution of the imaging device, with f50 being 0.7 – 0.9 line pairs per millimeter. The maximal exposure of an image was 95 mR. We derived an empirical relationship between the exposure and the X‐ray technical settings. The other parameters of the system were quantitatively measured and generally met the requirements.The IGRT system is safe and reliable for clinical use as a target localization device. The measured data can be used as a benchmark for a quality assurance procedure.PACS number: 87.56‐v

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f_{1} = 0.6

lp/mm.…”

Section: Methodsmentioning

confidence: 99%

80 mA \times 200 ms, 100 mA \times 160 ms, 160 mA \times 100 ms, and 200 mA \times 80 ms

).…”

Section: Methodsmentioning

confidence: 99%

“…The repeatability of the X‐ray output was calculated (13) using

% Repeatability = \frac{(\frac{M a x i m u m m R - M i n i m u m m R}{2})}{A v e r a g e m R} \times 100 %^{,}

…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Clinical assessment and characterization of a dual‐tube kilovoltage X‐ray localization system in the radiotherapy treatment room

Lee

Jin

Guan

et al. 2008

J Applied Clin Med Phys

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show abstract

“…Over the past two decades, the progress in the development of advanced electronics and computer technology has led to the replacement of the conventional screen/film ͑SF͒ based radiography by flat-panel ͑FP͒ based digital radiography in many radiology departments. [3][4][5][6][7][8][9][10] However, the nature of projection chest radiography along with the use of an area detector as image receptor indicates that some fundamental problems still exist in the digital imaging format as it was in the conventional SF based radiography.…”

Section: Introductionmentioning

confidence: 99%

Comparison of scatter rejection and low‐contrast performance of scan equalization digital radiography (SEDR), slot‐scan digital radiography, and full‐field digital radiography systems for chest phantom imaging

et al. 2010

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Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography ͑SEDR͒ technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel ͑FP͒ detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios ͑SPRs͒, a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads ͑3 mm in diameter͒ was used as the low-contrast objects to measure the contrast ratios ͑CRs͒ and contrast-to-noise ratios ͑CNRs͒ for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR ͑percentage of SPRs reduced with scatter removal/ rejection methods relative to that for nongrid full-field imaging͒ averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid fullfield imaging by 259%, 279%, and 145% for SEDR, slot-scan, and full-field with grid, respectively. The average CNR over four regions was found to improve over that for nongrid full-field imaging by 201% for SEDR as compared to 133% for the slot-scan technique and 14% for the antiscatter grid method. Conclusions: Both SEDR and slot-scan techniques outperformed the antiscatter grid method used in standard full-field radiography. For imaging with the same effective exposure, the SEDR technique offers no advantage over the slot-scan method in terms of SPRs and CRs. However, it improves CNRs significantly, especially in heavily attenuating regions. The improvement of lowcontrast performance may help improve the detection of the lung nodules or other abnormalities and may offer SEDR the potential for dose reduction in chest radiography.

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Projection X-ray Imaging

2019

Hendee's Physics of Medical Imaging, Fifth Edition

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Imaging Characteristics of an Amorphous Silicon Flat-Panel Detector for Digital Chest Radiography

Abstract: The FPD provides radiographic images with excellent inherent physical image quality.

Cited by 119 publications

References 9 publications

Clinical assessment and characterization of a dual‐tube kilovoltage X‐ray localization system in the radiotherapy treatment room

Clinical assessment and characterization of a dual‐tube kilovoltage X‐ray localization system in the radiotherapy treatment room

Comparison of scatter rejection and low‐contrast performance of scan equalization digital radiography (SEDR), slot‐scan digital radiography, and full‐field digital radiography systems for chest phantom imaging

Projection X-ray Imaging

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