Optimization of the exposure parameters in digital mammography using contrast-detail metrics

Rojas, Leidy J.; Fausto, Agnes M. F.; Mól, A. W.; Velasco, Fermín García; Abreu, P.O.S.; Henriques, Gabrielle M.; Furquim, Tânia Aparecida Correia

doi:10.1016/j.ejmp.2017.08.001

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…In order to probe the image quality with respect to dose, we utilize so called FOM parameter. 24,25 We replaced the radiation dose quantities used in these publications by DAP, as in…”

Section: Methodsmentioning

confidence: 99%

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Air gap technique is recommended in axiolateral hip radiographs

Kivistö

Kotiaho

Henner

et al. 2020

J Applied Clin Med Phys

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Purpose To investigate the replacement of conventional grid by air gap in axiolateral hip radiographs. The optimal air gap distance was studied with respect to radiation dose and image quality using phantom images, as well as 26 patient axiolateral hip radiographs. Methods The CDRAD phantom, along with polymethylmethacrylate slabs with thicknesses of 10.0, 14.6, and 20.0 cm was employed. The inverse image quality index and dose area product (DAP), as well as their combination, so called figure‐of‐merit (FOM) parameter, were evaluated for these images, with air gaps from 20 to 50 cm in increments of 10 cm. Images were compared to those acquired using a conventional grid utilized in hip radiography. Radiation dose was measured and kept constant at the surface of the detector by using a reference dosimeter. Verbal consent was asked from 26 patients to participate to the study. Air gap distances from 20 to 50 cm and tube current‐time products from 8 to 50 mAs were employed. Exposure index, DAP, as well as patient height and weight were recorded. Two radiologists evaluated the image quality of 26 hip axiolateral projection images on a 3‐point nondiagnostic — good/sufficiently good — too good scale. Source‐to‐image distance of 200 cm and peak tube voltage of 90 kVp were used in both studies. Results and conclusion Based on the phantom study, it is possible to reduce radiation dose by replacing conventional grid with air gap without compromising image quality. The optimal air gap distance appears to be 30 cm, based on the FOM analysis. Patient study corroborates this observation, as sufficiently good image quality was found in 24 of 26 patient radiographs, with 7 of 26 images obtained with 30 cm air gap. Thus, air gap method, with an air gap distance of 30 cm, is recommended in axiolateral hip radiography.

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“…In order to probe the image quality with respect to dose, we utilize so called FOM parameter. 24,25 We replaced the radiation dose quantities used in these publications by DAP, as in…”

Section: Methodsmentioning

confidence: 99%

“…IQF inv and DAP values were determined for all PMMA slab thicknesses and air gap distances. In order to probe the image quality with respect to dose, we utilize so called FOM parameter 24,25 . We replaced the radiation dose quantities used in these publications by DAP, as in

FOM = \frac{{IQF}_{inv}^{2}}{DAP} .

…”

Section: Methodsmentioning

confidence: 99%

Air gap technique is recommended in axiolateral hip radiographs

Kivistö

Kotiaho

Henner

et al. 2020

J Applied Clin Med Phys

View full text Add to dashboard Cite

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“…This is particularly favours the detectability of lesions such as lung cancers in CXR. [42,43]. To the best of our knowledge, our proposed and utilised method for evaluation and comparing the imaging systems performance, within and between hospitals, based on a FOM concept that has not been used before.…”

Section: Image Quality Versus Radiation Dose/ Fommentioning

confidence: 99%

A novel method for comparing radiation dose and image quality, between and within different x-ray units in a series of hospitals

et al. 2018

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Objectives: To develop a novel method for comparing radiation dose and image quality (IQ) to evaluate adult chest X-ray (CXR) imaging among several hospitals. Methods: CDRAD 2.0 phantom was used to acquire images in eight hospitals (17 digital X-ray units) using local adult CXR protocols. IQ was represented by image quality figure inverse (IQFinv), measured using CDRAD analyser software. Signal to noise ratio (SNR), contrast to noise ratio (CNR) and conspicuity index (CI) were calculated as additional measures of IQ. Incident air kerma (IAK) was calculated using a solid-state dosimeter for each acquisition. Figure of merit (FOM) was calculated to provide a single estimation of IQ and radiation dose.Results: IQ, radiation dose and FOM varied considerably between hospitals and X-ray units. For IQFinv, the mean (range) between and within the hospitals were 1.42 (0.83-2.18) and 1.87 (1.52-2.18), respectively. For IAK, the mean (range) between and within the hospitals were ) µGy, respectively. For FOM, the mean (range) between and within hospitals were 0.

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“…The former applies to the raw images, while the latter is based on clinical images presented to radiologists. The images presented to clinicians are derived from the raw images by employing nonlinear processing algorithms to enhance the low contrast between breast tissue and pathological findings [6]. While CDMAM phantoms may not be suitable to detect an impact of these processing algorithms (cf.…”

Section: Introductionmentioning

confidence: 99%

Determination of contrast-detail curves in mammography image quality assessment by a parametric model observer

et al. 2019

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A novel approach is proposed for the determination of contrast-detail curves in mammography image quality assessment. The approach is compared with current practice using virtual mammography.A binary parametric model observer is applied to images of the CDMAM phantom. The observer accounts for the simple disc shaped objects in the phantom and is applied separately to each cell of the phantom. For each of these applications, the area under the ROC curve (AUC) of the model observer is determined. The different AUCs, calculated from different applications of the parametric model observer, are then combined to a single contrastdetail curve quantifying the ability of the observer to detect details in the images. Virtual mammography is developed as a tool to simulate X-ray images of single CDMAM cells and to quantitatively assess the approach in comparison with current practice.It is shown that the proposed approach can lead to similar contrast-detail curves as current practice. The precision of the estimated contrast-detail curves is increased, i.e. using 5 images yields about the same precision for the proposed approach as 16 images when applying current practice.We conclude that contrast-detail curves in mammography image quality assessment can also be determined through the AUC of a binary parametric model observer. Since the proposed approach has higher precision than current practice, it is a promising candidate for contrast-detail analysis in mammography image quality assessment.

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Optimization of the exposure parameters in digital mammography using contrast-detail metrics

Cited by 10 publications

References 17 publications

Air gap technique is recommended in axiolateral hip radiographs

Air gap technique is recommended in axiolateral hip radiographs

A novel method for comparing radiation dose and image quality, between and within different x-ray units in a series of hospitals

Determination of contrast-detail curves in mammography image quality assessment by a parametric model observer

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