The Essential Physics of Medical Imaging

Bushberg, Jerrold T.; Seibert, J. Anthony; Leidholdt, Edwin M.; Boone, John M.; Goldschmidt, Edward

doi:10.1118/1.1585033

Cited by 1,219 publications

(1,987 citation statements)

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“…1 Bone marrow is rather sensitive to radiation: in humans, whole-body dosages starting at about 250 mGy lead to reduced lymphocyte counts. 5 A single dose of 5 Gy led to significant changes in bone regeneration, while a 2.5-Gy dose did not. 6 A 2-Gy dose resulted in alternative growth-plate structures.…”

Section: Introductionmentioning

confidence: 99%

No effects of in vivo micro‐CT radiation on structural parameters and bone marrow cells in proximal tibia of wistar rats detected after eight weekly scans

Brouwers

Rietbergen

Huiskes

2007

Journal Orthopaedic Research

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Recently developed in vivo animal high-resolution micro-CT scanners offer the possibility to monitor longitudinal changes in bone microstructure of small rodents, but may impose high radiation doses that could damage bone tissue. The goal of this study was to determine the effects on the bone of 8 weeks of in vivo scanning of the proximal tibia in female Wistar rats. Eight weekly CT scans were made of the right proximal tibia of nine female, 30-week-old, retired-breeder, Wistar rats. Two weeks after the last weekly scan, a final scan was made. The left leg was only scanned during first and final measurements and served as a control. A two-way ANOVA with repeated measures was performed on the first and last measurements of left and right tibiae for six bone structural parameters. Bone marrow cells were flushed out and tested for cell viability. No significant difference was found between left and right for any of the bone structural parameters ( p > 0.05). Structure model index and trabecular separation significantly changed as a result of aging, while none of the other parameters did. No significant difference was found between left and right in absolute and percentage number of cell viability. We did not find any indication that the applied scanning regime, in combination with the particular settings used, would affect the results of in vivo bone structural measurements in long-term studies using aged, female Wistar rats. However, careful consideration should be made when determining the number of scans, particularly when a different experimental design is used. ß

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Section: Introductionmentioning

confidence: 99%

No effects of in vivo micro‐CT radiation on structural parameters and bone marrow cells in proximal tibia of wistar rats detected after eight weekly scans

Brouwers

Rietbergen

Huiskes

2007

Journal Orthopaedic Research

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“…CT has become an indispensable component of virtually every radiology department 1,3 ; improvements in speed and resolution have seen it emerge as the workhorse for many radiological studies. Despite its usefulness, current CT detector systems waste much of the information carried by incident photons.…”

Section: Dual-energy and Spectroscopic Ctmentioning

confidence: 99%

“…Digital subtraction of dual-energy CT images uses differences in attenuation to identify different tissues or contrast agents 3,[7][8] . The method requires two scans at different energies, which are digitally subtracted to exploit different tissue's energy-dependent absorptions.…”

Section: Dual-energy and Spectroscopic Ctmentioning

confidence: 99%

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Spectroscopic biomedical imaging with the Medipix2 detector

Melzer

Cook

Butler

et al. 2008

Australas. Phys. Eng. Sci. Med.

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This study confirms that the Medipix2 x-ray detector enables spectroscopic bio-medical plain radiography. We show that the detector has the potential to provide new, useful information beyond the limited spectroscopic information of modern dual-energy computed tomography (CT) scanners. Full spectroscopic 3D-imaging is likely to be the next major technological advance in computed tomography, moving the modality towards molecular imaging applications. This paper focuses on the enabling technology which allows spectroscopic data collection and why this information is useful. In this preliminary study we acquired the first spectroscopic images of human tissue and other biological samples obtained using the Medipix2 detector. The images presented here include the clear resolution of the 1.4mm long distal phalanx of a 20 week old miscarried foetus, showing clear energy-dependent variations. The opportunities for further research using the forthcoming Medipix3 detector are discussed and a prototype spectroscopic CT scanner (MARS, Medipix All Resolution System) is briefly described.

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“…As noise distributions in MRI images are nearly white Gaussian for signal-to-noise ratios (SNR) greater than 2 (Gudbjartsson and Patz, 1995), we added independent realizations of white Gaussian noise to our simulated dataset. We measured the amount of added noise as a signal-to-noise ratio according to Bushberg et al (2002): SNR = A/a n (20) where A is the mean image pixel intensity, and o" is the standard deviation of the Gaussian noise. Different levels of Gaussian noise were added to the simulated data ranging from SNR 3 to SNR 7.…”

Section: Simulated Images Datasetmentioning

confidence: 99%

Organ-focused mutual information for nonrigid multimodal registration of liver CT and Gd–EOB–DTPA-enhanced MRI

Fernandez-de-Manuel

Wollny

Kybic

et al. 2014

Medical Image Analysis

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Accurate detection of liver lesions is of great importance in hepatic surgery planning. Recent studies have shown that the detection rate of liver lesions is significantly higher in gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-enhanced MRI) than in contrast-enhanced portal-phase computed tomography (CT); however, the latter remains essential because of its high specificity, good performance in estimating liver volumes and better vessel visibility. To characterize liver lesions using both the above image modalities, we propose a multimodal nonrigid registration framework using organ-focused mutual information (OF-MI). This proposal tries to improve mutual information (MI) based registration by adding spatial information, benefiting from the availability of expert liver segmentation in clinical protocols. The incorporation of an additional information channel containing liver segmentation information was studied. A dataset of real clinical images and simulated images was used in the validation process. A Gd-EOB-DTPA-enhanced MRI simulation framework is presented. To evaluate results, warping index errors were calculated for the simulated data, and landmark-based and surface-based errors were calculated for the real data. An improvement of the registration accuracy for OF-MI as compared with MI was found for both simulated and real datasets. Statistical significance of the difference was tested and confirmed in the simulated dataset (p < 0.01).

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The Essential Physics of Medical Imaging

Abstract: A guide to the fundamental principles of medical imaging physics, radiation protection and radiation biology, with complex topics presented in the clear and concise manner and style for which these authors are known.

Cited by 1,219 publications

References 0 publications

No effects of in vivo micro‐CT radiation on structural parameters and bone marrow cells in proximal tibia of wistar rats detected after eight weekly scans

No effects of in vivo micro‐CT radiation on structural parameters and bone marrow cells in proximal tibia of wistar rats detected after eight weekly scans

Spectroscopic biomedical imaging with the Medipix2 detector

Organ-focused mutual information for nonrigid multimodal registration of liver CT and Gd–EOB–DTPA-enhanced MRI

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