A patient‐equivalent attenuation phantom for estimating patient exposures from automatic exposure controlled x‐ray examinations of the abdomen and lumbo–sacral spine

Conway, Burton J.; Duff, J. E.; Fewell, Thomas R.; Jennings, Robert J.; Rothenberg, L. N.; Fleischman, Richard C.

doi:10.1118/1.596483

Cited by 28 publications

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“…The phantom consists of an adult male human skeleton embedded in tissue simulating plastic [17,18]. It is designed to simulate an average large (e.g.…”

Section: Methodsmentioning

confidence: 99%

Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

et al. 2007

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BackgroundIt is estimated that 60 million computed tomography (CT) scans were performed during 2006, with approximately 11% of those performed on children age 0–15 years. Various types of gonadal shielding have been evaluated for reducing exposure to the gonads. The purpose of this study was to quantify the radiation dose reduction to the gonads and its effect on image quality when a wrap-around male pediatric gonad shield was used during CT scanning. This information is obtained to assist the attending radiologist in the decision to utilize such male gonadal shields in pediatric imaging practice.MethodsThe dose reduction to the gonads was measured for both direct radiation and for indirect scattered radiation from the abdomen. A 6 cm3 ion chamber (Model 10X5-6, Radcal Corporation, Monrovia, CA) was placed on a Humanoid real bone pelvic phantom at a position of the male gonads. When exposure measurements with shielding were made, a 1 mm lead wrap-around gonadal shield was placed around the ion chamber sensitive volume.ResultsThe use of the shields reduced scatter dose to the gonads by a factor of about 2 with no appreciable loss of image quality. The shields reduced the direct beam dose by a factor of about 35 at the expense of extremely poor CT image quality due to severe streak artifacts.ConclusionImages in the direct exposure case are not useful due to these severe artifacts and the difficulties in positioning these shields on patients in the scatter exposure case may not be warranted by the small absolute reduction in scatter dose unless it is expected that the patient will be subjected to numerous future CT scans.

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“…The phantom consists of an adult male human skeleton embedded in tissue simulating plastic [17,18]. It is designed to simulate an average large (e.g.…”

Section: Methodsmentioning

confidence: 99%

Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

et al. 2007

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“…In order to simulate the attenuation of x-rays by a patient in neuro-EIGIs, a custom phantom is used with the test objects to mimic the attenuation of x-rays by a human head. While the ANSI/AAPM head phantom has been recommended for lateral projections [2.5 cm acrylic + 2 mm Al + 10 cm acrylic + 1 mm Al + 2.5 cm of acrylic (Figure 6)] [9] , it has been reported that this phantom is not suitable for measurements involving frontal skull imaging as used in most neuro-EIGI procedures [10] . For this experiment, a head phantom is used that consists of 2.5 cm acrylic + 7 mm Al + 10 cm acrylic + 6 mm Al + 2.5 cm of acrylic and was constructed using NEMA phantom blocks (Figure 7).…”

Section: Methodsmentioning

confidence: 99%

Detector system comparison using relative CNR for specific imaging tasks related to neuro-endovascular image-guided interventions (neuro-EIGIs)

et al. 2014

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Neuro-EIGIs require visualization of very small endovascular devices and small vessels. A Microangiographic Fluoroscope (MAF) x-ray detector was developed to improve on the standard flat panel detector’s (FPD’s) ability to visualize small objects during neuro-EIGIs. To compare the performance of FPD and MAF imaging systems, specific imaging tasks related to those encountered during neuro-EIGIs were used to assess contrast to noise ratio (CNR) of different objects. A bar phantom and a stent were placed at a fixed distance from the x-ray focal spot to mimic a clinical imaging geometry and both objects were imaged by each detector system. Imaging was done without anti-scatter grids and using the same conditions for each system including: the same x-ray beam quality, collimator position, source to imager distance (SID), and source to object distance (SOD). For each object, relative contrasts were found for both imaging systems using the peak and trough signals. The relative noise was found using mean background signal and background noise for varying detector exposures. Next, the CNRs were found for these values for each object imaged and for each imaging system used. A relative CNR metric is defined and used to compare detector imaging performance. The MAF utilizes a temporal filter to reduce the overall image noise. The effects of using this filter with the MAF while imaging the clinical object’s CNRs are reported. The relative CNR for the detectors demonstrated that the MAF has superior CNRs for most objects and exposures investigated for this specific imaging task.

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“…The PEP is lightweight and transportable. It is constructed of readily available materials and accurately simulates the standard patient's attenuation properties [13,14].…”

Section: Introductionmentioning

confidence: 99%

Construction of pediatric homogeneous phantoms for optimization of chest and skull radiographs

Alves

Miranda

Neto

et al. 2015

European Journal of Radiology

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A patient‐equivalent attenuation phantom for estimating patient exposures from automatic exposure controlled x‐ray examinations of the abdomen and lumbo–sacral spine

Cited by 28 publications

References 0 publications

Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

Radiation dose reduction at a price: the effectiveness of a male gonadal shield during helical CT scans

Detector system comparison using relative CNR for specific imaging tasks related to neuro-endovascular image-guided interventions (neuro-EIGIs)

Construction of pediatric homogeneous phantoms for optimization of chest and skull radiographs

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