A comparative analysis of OTF, NPS, and DQE in energy integrating and photon counting digital x‐ray detectors

Acciavatti, Raymond J.; Maidment, Andrew D. A.

doi:10.1118/1.3505014

Cited by 31 publications

(37 citation statements)

References 45 publications

(50 reference statements)

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“…[25][26][27] In this setting, the PSF is the convolution of the phosphor blurring function with the detector element sampling function. [48][49][50] An additional subtlety that may be modeled is the blurring of the focal spot. The MTF of the focal spot is degraded with increasing focal spot size, 51 as well as with increasing focal spot motion during a continuous DBT scan.…”

Section: Discussionmentioning

confidence: 99%

Optimization of phosphor‐based detector design for oblique x‐ray incidence in digital breast tomosynthesis

Acciavatti

Maidment

2011

Medical Physics

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Purpose: In digital breast tomosynthesis (DBT), a volumetric reconstruction of the breast is generated from a limited range of x-ray projections. One trade-off of DBT is resolution loss in the projections due to non-normal (i.e., oblique) x-ray incidence. Although degradation in image quality due to oblique incidence has been studied using empirical data and Monte Carlo simulations, a theoretical treatment has been lacking. The purpose of this work is to extend Swank's calculations of the transfer functions of turbid granular phosphors to oblique incidence. The model is ultimately used as a tool for optimizing the design of DBT detectors. Methods: A quantum-limited system and 20 keV x-rays are considered. Under these assumptions, the modulation transfer function (MTF) and noise power spectra (NPS) are derived using the diffusion approximation to the Boltzmann equation to model optical scatter within the phosphor. This approach is applicable to a nonstructured scintillator such as gadolinium oxysulfide doped with terbium (Gd 2 O 2 S:Tb), which is commonly used in breast imaging and which can reasonably approximate other detector materials. The detective quantum efficiency (DQE) is then determined from the Nishikawa formulation, where it is written as the product of the x-ray quantum detection efficiency, the Swank factor, and the Lubberts fraction. Transfer functions are calculated for both front-and back-screen configurations, which differ by positioning the photocathode at the exit or entrance point of the x-ray beam, respectively. Results: In the front-screen configuration, MTF and DQE are found to have considerable angular dependence, while NPS is shown to vary minimally with projection angle. As expected, the high frequency MTF and DQE are degraded substantially at large angles. By contrast, all transfer functions for the back-screen configuration have the advantage of significantly less angular dependence. Using these models, we investigated the possibility for optimizing the design of DBT detectors. As an example optimization strategy, the phosphor thickness which maximizes the DQE at a fixed frequency is analyzed. This work demonstrates that the optimal phosphor thickness for the frontscreen is angularly dependent, shifting to lower thickness at higher angles. Conversely, the backscreen is not optimized by a single thickness but instead attains reasonably high DQE values over a large range of thicknesses. Although the back-screen configuration is not suited for current detectors using a glass substrate, it may prove to be preferred in future detectors using newly proposed plastic thin-film transistor (TFT) substrates. Conclusions: Using the diffusion approximation to the Boltzmann equation to model the spread of light in a scintillator, this paper develops an analytical model of MTF, NPS, and DQE for a phosphor irradiated obliquely. The model is set apart from other studies on oblique incidence in being derived from first principles. This work has applications in the optimization of DBT detector design.

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Section: Discussionmentioning

confidence: 99%

Optimization of phosphor‐based detector design for oblique x‐ray incidence in digital breast tomosynthesis

Acciavatti

Maidment

2011

Medical Physics

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“…It's a 4D imaging technology of living human body's physiology, biochemistry, function and metabolism. ''Modeling'' is mainly probing into 3D modeling from medical imaging for dosimetry studies (Acciavatti and Maidment 2010;Salama et al 2010;Gallo et al 2010;Zudilova-Seinstra et al 2010;Salomon et al 2010;Bibin et al 2010;Wang 2002). There are four clusters in mean year 2002 (#0 tomosynthesis, #4 conebeam, #11 reversible watermarking, #12 phase contrast).…”

Section: Panorama Of Digital Medicine Domainmentioning

confidence: 99%

Visualizing the structure and the evolving of digital medicine: a scientometrics review

Fang

2015

Scientometrics

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This article aims to analyze and visualize the structure and the emerging trend of digital medicine, a new medical pattern of twenty-first century. Our study objectively explores the document co-citation clusters of 6060 bibliographic records to identify the origin of digital medicine and the hot research specialty of domain. Pivotal point articles, prominent authors, active disciplines and institution have been identified by network analysis theory. CiteSpace was used to visualize the perspective of digital medicine domain. As an interdiscipline which integrated computer science, information engineering with medicine, digital medicine originally and mainly on digital medical imaging technology research for accuracy and speedy clinical diagnosis and therapy. Of 6060 relevant records reviewed, 1719 (28 %) are on radiology, 902 (15 %) are on engineering, 539 (9 %) are on computer science. The largest co-citation cluster is on digital tomosynthesis. The earliest cluster is on medical imaging segmentation and registration. Post-processing imaging technology, detector, phase contrast, reversible watermarking, input, model 3D reconstruct, real-time dynamic imaging, dosimetry have been the hot research topics. The recently cluster is on internet health information. Harvard University of USA is the prominent institution. The coverage of digital medicine research is widely from clinic to laboratory. Recent year, domain research front is thematically on teleradiology, telemedicine and hospital information management system.

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“…Several studies have been published on how to model the frequency‐dependent detective quantum efficiency of photon‐counting detectors, but these studies do not take energy information into account. At the same time, the impact of detector nonidealities on spectral imaging tasks has been studied by several authors .…”

Section: Introductionmentioning

confidence: 99%

A framework for performance characterization of energy‐resolving photon‐counting detectors

2018

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We have developed a framework for assessing the performance of photon-counting energy-resolving detectors and shown that the matrix-valued NEQ and DQE metrics contain sufficient information for calculating the dose efficiency for both detection and quantification tasks, the task having any spatial and energy dependence. This framework will be beneficial for the development and optimization of photon-counting x-ray detectors.

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A comparative analysis of OTF, NPS, and DQE in energy integrating and photon counting digital x‐ray detectors

Cited by 31 publications

References 45 publications

Optimization of phosphor‐based detector design for oblique x‐ray incidence in digital breast tomosynthesis

Optimization of phosphor‐based detector design for oblique x‐ray incidence in digital breast tomosynthesis

Visualizing the structure and the evolving of digital medicine: a scientometrics review

A framework for performance characterization of energy‐resolving photon‐counting detectors

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