Prof. Michael Sandborg Profile

Prof. Michael Sandborg

Medical Physicist at Linköping Univ

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Publications (12)

SPIE Journal Paper | 20 November 2020

Development and assessment of a quality assurance device for radiation field–light field congruence testing in diagnostic radiology

Jan Lindström, Markus Hulthén, Michael Sandborg, Åsa Carlsson-Tedgren

JMI, Vol. 7, Issue 06, 063501, (November 2020) https://doi.org/10.1117/12.10.1117/1.JMI.7.6.063501

KEYWORDS: X-rays, Lithium, Sensors, Particles, Prototyping, Diagnostics, X-ray imaging, Standards development, Manufacturing, Image sensors

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Purpose: Existing methods for checking the light field–radiation field congruence on x-ray equipment either do not fully meet the conditions of various quality control standards regarding inherent uncertainty requirements or contain subjective steps, further increasing the uncertainty of the end result. The aim of this work was to develop a method to check the light field–radiation field congruence on all x-ray equipment. The result should have a low uncertainty which is accomplished by eliminating most subjective user steps in the method. A secondary aim was to maintain the same level of usability as of comparable methods but still able to store the result. Approach: A new device has been developed where the light field and corresponding radiation field are monitored through measurements of the field edge locations (in total: 2 × 4 edges). The maximum field size location deviation between light field and radiation field in the new method is constrained by the physical limitations of the sensors used in various versions of the prototype: linear image sensors (LISs) of 25 to 29 mm active sensor length. The LISs were sensitized to x-rays by applying a phosphor strip of Gd2O2S : Tb covering the light sensor input area. Later prototypes of the completed LIS device also have the option of a Bluetooth (100-m range standard) connection, thus increasing the mobility. Results: The developed device has a special feature of localization a field edge without any prior, subjective, alignment procedure of the user, i.e., the signals produced were processed by software storing the associated field edge profiles, localizing the edges in them, and finally displaying the calculated deviation. The uncertainty in field edge location difference was estimated to be <0.1 mm (k = 2). The calculated uncertainty is lower than for other, commercially available, methods for light field–radiation field congruence also presented in this work. Conclusions: A method to check the light field–radiation field congruence of x-ray systems was developed to improve the limitations found in existing methods, such as device detector resolution, subjective operator steps, or the lack of storing results for later analysis. The development work overcame several challenges including mathematically describing real-life edges of light and radiation fields, noise reduction of radiation edges, and mapping/quantification of the rarely observed phenomenon of focal spot wandering. The assessment of the method showed that the listed limitations were overcome, and the aims were accomplished. It is therefore believed that the device can improve the work in quality controls of x-ray systems.

Proceedings Article | 19 March 2014 Paper

Prostate tissue decomposition via DECT using the model based iterative image reconstruction algorithm DIRA

Alexandr Malusek, Maria Magnusson, Michael Sandborg, Robin Westin, Gudrun Alm Carlsson

Proceedings Volume 9033, 90333H (2014) https://doi.org/10.1117/12.2043445

KEYWORDS: Tissues, Prostate, Bone, Calcium, Signal attenuation, Reconstruction algorithms, Image restoration, Computed tomography, Proteins, Radiotherapy

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Proceedings Article | 19 March 2014 Paper

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

Jan Lindström, Markus Hulthén, Gudrun Alm Carlsson, Michael Sandborg

Proceedings Volume 9033, 90333R (2014) https://doi.org/10.1117/12.2042921

KEYWORDS: X-rays, Particles, Staring arrays, Charge-coupled devices, Phosphorescence, Diagnostics, Radiology, CCD cameras, Instrument modeling, Sensors

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Proceedings Article | 7 March 2012 Paper

Quantifying effects of post-processing with visual grading regression

Örjan Smedby, Mats Fredrikson, Jakob De Geer, Michael Sandborg

Proceedings Volume 8318, 83181N (2012) https://doi.org/10.1117/12.912321

KEYWORDS: Visualization, Image quality, Statistical analysis, Image filtering, Heart, Visual analytics, Computed tomography, Digital filtering, Image quality standards, Visual process modeling

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Proceedings Article | 22 February 2012 Paper

Visual grading regression with random effects

Örjan Smedby, Mats Fredrikson, Jakob De Geer, Michael Sandborg

Proceedings Volume 8318, 831805 (2012) https://doi.org/10.1117/12.913650

KEYWORDS: Visualization, Image quality, Image quality standards, Statistical analysis, Visual analytics, Image filtering, Computed tomography, Diagnostics, Angiography, Digital filtering

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Proceedings Article | 17 March 2011 Paper

Investigation of the effect of varying scatter-to-primary ratios on nodule contrast in chest tomosynthesis

Angelica Svalkvist, Gustaf Ullman, Markus Håkansson, David Dance, Michael Sandborg, Gudrun Alm Carlsson, Magnus Båth

Proceedings Volume 7961, 79615Y (2011) https://doi.org/10.1117/12.873173

KEYWORDS: Monte Carlo methods, Chest, Optical spheres, Lung, Sensors, Signal detection, Medicine, Computed tomography, Photons, Physics

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Proceedings Article | 2 March 2006 Paper

Calculation of images from an anthropomorphic chest phantom using Monte Carlo methods

Gustaf Ullman, Alexandr Malusek, Michael Sandborg, David Dance, Gudrun Alm Carlsson

Proceedings Volume 6142, 614239 (2006) https://doi.org/10.1117/12.644119

KEYWORDS: Monte Carlo methods, Imaging systems, Sensors, Photons, Chest, Signal to noise ratio, Lung, Visualization, Image quality, Image segmentation

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Proceedings Article | 4 May 2004 Paper

Comparison of two methods for evaluation of image quality of lumbar spine radiographs

Anders Tingberg, Magnus Bath, Markus Hakansson, Joakim Medin, Michael Sandborg, Gudrun Alm-Carlsson, Sören Mattsson, Lars Gunnar Mansson

Proceedings Volume 5372, (2004) https://doi.org/10.1117/12.534040

KEYWORDS: Image quality, Modulation transfer functions, Spine, Radiography, Image analysis, Spatial resolution, Visualization, Visual analytics, Visibility, Bone

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Proceedings Article | 5 June 2003 Paper

Simulation of scatter in cone beam CT: effects on projection image quality

Alexandr Malusek, Michael Sandborg, Gudrun Carlsson

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.479940

KEYWORDS: Head, Monte Carlo methods, Chest, Scattering, Sensors, Image quality, Photon transport, X-ray computed tomography, Computed tomography, Error analysis

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Proceedings Article | 28 May 1999 Paper

Calibration and validation of a voxel phantom for use in the Monte Carlo modeling and optimization of x-ray imaging systems

David Dance, Graham McVey, Michael Sandborg, Jan Persliden, Gudrun Carlsson

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349533

KEYWORDS: Chest, Spine, Monte Carlo methods, Imaging systems, Lung, Tissues, Absorbance, Systems modeling, X-ray imaging, Backscatter

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Proceedings Article | 28 May 1999 Paper

Optimization of chest and lumbar spine radiography by Monte Carlo modeling of the patient and imaging system

Michael Sandborg, Graham McVey, David Dance, Gudrun Carlsson, Francis Verdun

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349521

KEYWORDS: Image quality, Imaging systems, Chest, Spine, Monte Carlo methods, Absorbance, Signal to noise ratio, Lung, Blood vessels, Systems modeling

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Proceedings Article | 11 April 1996 Paper

Receptor modeling for use in computerized optimization of imaging systems

Michael Sandborg, Gudrun Carlsson, David Dance, Jan Persliden

Proceedings Volume 2708, (1996) https://doi.org/10.1117/12.237818

KEYWORDS: Receptors, Photons, Modulation transfer functions, Signal to noise ratio, Imaging systems, X-rays, Image quality, Monte Carlo methods, Systems modeling, Spatial frequencies

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Showing 5 of 12 publications

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