Open low-field magnetic resonance imaging in radiation therapy treatment planning

Krempien, Robert; Schubert, Kai; Zierhut, Dietmar; Steckner, Michael; Treiber, M.; Harms, Wolfgang; Mende, Ulrich; Latz, D.; Wannenmacher, M; Wenz, Frederik

doi:10.1016/s0360-3016(02)02886-9

Cited by 55 publications

(33 citation statements)

References 33 publications

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“…Therefore, the actual rectal wall volume difference for the same amount of dose between CT and MRI delineation can be estimated to be 7.5% (4% ϩ 3.5%). This is in line with other studies in which MRI delineation was applied, where the rectal wall volume receiving the same amount of dose was reduced by approximately 10% (20,21).…”

Section: Dose Comparisonsupporting

confidence: 91%

Impact of knee support and shape of tabletop on rectum and prostate position

Steenbakkers

Duppen

Betgen

et al. 2004

International Journal of Radiation Oncology*Biology*Physics

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Section: Dose Comparisonsupporting

confidence: 91%

Impact of knee support and shape of tabletop on rectum and prostate position

Steenbakkers

Duppen

Betgen

et al. 2004

International Journal of Radiation Oncology*Biology*Physics

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“…18,19 Similar large μ-oxo-bridged Gd 3+ -ion clusters within (or upon) the GNTs are consistent with their ability to retain individual Gd 3+ ions under physiological conditions (PBS, pH = 7.4). 20 While the current trend in MRI will likely continue toward higher fields (>1.5 T), open-low-field MRI 21,22 (between 0.1 and 1 T) and ultra-low-field MRI 23,24 (<150 μT) offer advantages for some situations. Low-field MRI scanners are not only cost-effective but are advantageous when imaging in the presence of metal implants, where large and expensive magnets might be impractical and for patients who suffer from claustrophobia.…”

mentioning

confidence: 99%

The Gadonanotubes as High-Performance MRI Contrast Agents: The Unappreciated Role of the Carbon Nanotube Component at Low Magnetic Fields

Moghaddam¹,

Sethi²,

Shayeganfar³

et al. 2017

ECS J. Solid State Sci. Technol.

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The Gadonanotubes (GNTs) are the highest-performing T 1 -weighted MRI contrast agent material known with a relaxivity of ∼160 mM −1 s −1 per Gd 3+ ion at 1.5 T. In this work, the contribution of carbon-based free radicals at defect sites on the sidewalls of the ultra-short carbon nanotube (US-tube) component of the GNTs to the T 1 relaxation time has been investigated by Nuclear Magnetic Resonance Dispersion (NMRD) and Electron Paramagnetic Resonance (EPR) studies. The NMRD results indicate that carbon-based radicals of the US-tube structure substantially shorten water proton spin-lattice relaxation times at low frequencies (< 1 MHz) and that the high water proton relaxation rate for the GNTs at these fields does not result from the Gd 3+ ion alone. Furthermore, a computational study suggests that the defect sites of the US-tube structure increase nanotube strain and create new interband electronic states. While the presence of Gd 3+ ions at the defect sites for the GNTs do not induce new electronic states, they do introduce a shift in the Fermi level to higher energy (0.4 eV).

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“…A 3D multi-compartment phantom has been used to perform geometric distortion studies [9,11]. Some 3D phantoms were used to study the effects of geometric distortion at 0.2 T and 1.5 T MRI respectively, in radiotherapy treatment planning of prostate cancer [12][13][14][15]. The geometric distortion is related to field-strength and homogeneity and regarded as an important issue in MRI.…”

Section: Introductionmentioning

confidence: 99%

Geometric distortion evaluation using a multi-orientated water-phantom at 0.2 T MRI

Jao

Cheng

Lee

et al. 2015

BME

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Abstract. Magnetic Resonance Imaging (MRI) has been one of the most revolutionary medical imaging modalities in the past three decades. It has been recognized as a potential technique in the clinical diagnosis of diseases as well as tumor differentiation. Although MRI has now become the preferred choice in many clinical examinations, there are some drawbacks, which still limit its applications. One of the crucial issues of MRI is the geometric distortion caused by magnetic field inhomogeneity and susceptibility effects. The farther the lesion from the center of a magnetic field (off-center field), the more severe the distortion becomes, especially in low-field MRI. Hence, it might hinder the diagnosis and characterization of lesions in the presence of field inhomogeneity. In this study, an innovative multi-orientated water-phantom was used to evaluate the geometric distortion. The correlations between the level of image distortion and the relative off-center positions, as well as the variation of signal intensities, were both investigated. The image distortion ratios of axial, coronal and sagittal images were calculated.

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Open low-field magnetic resonance imaging in radiation therapy treatment planning

Cited by 55 publications

References 33 publications

Impact of knee support and shape of tabletop on rectum and prostate position

Impact of knee support and shape of tabletop on rectum and prostate position

The Gadonanotubes as High-Performance MRI Contrast Agents: The Unappreciated Role of the Carbon Nanotube Component at Low Magnetic Fields

Geometric distortion evaluation using a multi-orientated water-phantom at 0.2 T MRI

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