A scanning equalization system for improved chest radiography.

Plewes, D B; Wandtke, John C.

doi:10.1148/radiology.142.3.7063700

Cited by 26 publications

(9 citation statements)

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“…Although these techniques have gained some success, their acceptance has been limited (1,6,7,17). Scanning equalization radiography (SER) and advanced multiple beam equalization radiography (AMBER) are both sophisticated exposure systems which utilize a narrow X-ray beam or a fan beam, respectively, and an exposure which is controlled by a feedback mechanism (11,15,18,19). These systems provide an increase of X-ray to the high absorption areas such as the mediastinum without overexposing the lungs.…”

mentioning

confidence: 99%

Dynamic Range Control Processing of Digital Chest Images

Ikezoe¹,

Takeuchi²,

Shoji³

et al. 1996

Acta Radiol

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mentioning

confidence: 99%

Dynamic Range Control Processing of Digital Chest Images

Ikezoe¹,

Takeuchi²,

Shoji³

et al. 1996

Acta Radiol

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“…Technologies have been implemented to increase the exposures in the heavily attenuating regions and reduce the exposures in the lightly attenuating regions for applications in thoracic radiology and interventional radiology, with both scanning and area exposure equalization methods, all of which have demonstrated improved image quality and detectability of low-contrast objects in heavily attenuating regions. 13,24,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] We have developed a prototype scan equalization digital radiography ͑SEDR͒ system implemented with amorphous selenium ͑a-Se͒ based flat-panel detector. The system combines slot-scanning geometry with regional beam width modulation to reject scatter radiation effectively while regulating x-ray exposure regionally.…”

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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“…This method, namely exposure equalization, results in an increased exposure to the heavily attenuating regions and decreased exposure to the lightly attenuating regions. Several exposure equalization techniques have been implemented and investigated in the past (Peppler et al , 1982; Hasegawa et al , 1986; Hasegawa et al , 1987; Boone et al , 1993; Boone et al , 1995; Goodsitt et al , 1998; Rudin and Bednarek, 1980; Rudin et al , 1999; Fletcher et al , 1996; Molloi et al , 1999; Molloi et al , 2001; Lam and Chan, 1990; Vlasbloem and Kool, 1988; Chotas et al , 1990; Plewes and Wandtke, 1982; Plewes and Vogelstein, 1983; Wandtke et al , 1988; Kool et al , 1988; Panayiotakis et al , 1998; Sabol et al , 1993; Sabol et al , 1996;), all of which have demonstrated improved image quality particularly in the heavily attenuating regions. Exposure equalization radiography may be divided into two categories: those based on conventional full-field image acquisition and those based on spot-/slot-scan imaging geometry.…”

Section: Introductionmentioning

confidence: 99%

“…The scanning equalization radiography (SER) (Lam and Chan, 1990; Vlasbloem and Kool, 1988; Chotas et al , 1990; Plewes and Wandtke, 1982; Plewes and Vogelstein, 1983; Wandtke et al , 1988; Kool et al , 1988) on the other hand, employs spot-/slot-scan geometry to regulate the entrance exposure regionally while it rejects the scattered radiation effectively. Spatially and temporarily varying beam height or x-ray tube current pulse width modulation can be used to achieve exposure equalization during the scan.…”

Section: Introductionmentioning

confidence: 99%

Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience

et al. 2009

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It is well recognized in projection radiography that low-contrast detectability suffered in heavily attenuating regions due to excessively low x-ray fluence to the image receptor and higher noise levels. Exposure equalization can improve image quality by increasing the x-ray exposure to heavily attenuating regions, resulting in a more uniform distribution of exposure to the detector. Image quality is also expected to be improved by using the slot-scan geometry to reject scattered radiation effectively without degrading primary x-rays. This paper describes the design of prototype scan equalization digital radiography (SEDR) system implemented with an amorphous silicon (a-Si) thin-film transistor (TFT) array based flat-panel detector. With this system, the slot-scan geometry with the alternate line erasure and readout (ALER) technique was used to achieve scatter rejection. A seven-segment beam height modulator assembly was mounted onto the fore-collimator to regulate exposure regionally for chest radiography. The beam modulator assembly, consisting of micro linear motors, lead screw cartridge with lead beam blocks attached, position feedback sensors, and motor driver circuitry, has been tested and found to have an acceptable response for exposure equalization in chest radiography. An anthropomorphic chest phantom was imaged in the posterior-anterior (PA) view under clinical conditions. Scatter component, primary x-rays, scatter-to-primary ratios (SPRs), and primary signal-to-noise ratios (PSNRs) were measured in the SEDR images to evaluate the rejection and redistribution of scattered radiation, and compared with those for conventional full-field imaging with and without anti-scatter grid methods. SPR reduction ratios (SPRRRs, defined as the differences between the non-grid full-field SPRs and the reduced SPRs divided by the former) yielded approximately 59% for the full-field imaging with grid and 82% for SEDR technique in the lungs; and 77% for the full-field imaging with grid and 95% for SEDR technique in the subdiaphragm. The SEDR technique demonstrated a substantial improvement in PSNRs over the anti-scatter grid technique. The improvements of PSNRs are varied with the regions and are more pronounced in the heavily attenuating regions.

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A scanning equalization system for improved chest radiography.

Cited by 26 publications

References 0 publications

Dynamic Range Control Processing of Digital Chest Images

Dynamic Range Control Processing of Digital Chest Images

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

Scan equalization digital radiography (SEDR) implemented with an amorphous selenium flat-panel detector: initial experience

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