scholarly journals Clinically Delivered Treatment for Glioma Patients on Hybrid Magnetic Resonance Imaging (MRI)-Linear Accelerator (MR-Linac) versus Cone Beam CT (CBCT)-Guided Linac

2021 ◽  
Author(s):  
Michael H. Wang ◽  
Anthony Kim ◽  
Mark Ruschin ◽  
Hendrick Tan ◽  
Hany Soliman ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Monte Carlo ◽  
Magnetic Resonance ◽  
Linear Accelerator ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Skin Dose ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

Abstract Magnetic Resonance Imaging (MRI)-Linear Accelerator (MR-Linac) radiotherapy is an innovative technology that requires special consideration for secondary electron interactions within the magnetic field, which can alter dose deposition at air-tissue interfaces. Thirty-seven consecutive glioma patients had treatment planning completed and approved prior to radiotherapy initiation using commercial treatment planning systems (TPS): a Monte Carlo-based or convolution-based TPS for MR-Linac or Cone Beam CT (CBCT)-guided Linac, respectively. In vivo skin dose was measured using an Optically Stimulated Luminescent Dosimeter (OSLD) and correlated with TPS skin dose. We found that Monte Carlo-based MR-Linac plans and convolution-based CBCT-Linac plans had similar dosimetric parameters for target volumes and organs-at-risk. However, MR-Linac plans had 1.52 Gy higher mean dose to air cavities (p<0.0001) and 1.10 Gy higher mean dose to skin (p<0.0001). In vivo skin dose was 14.5% greater for MR-Linac (p=0.0027), and were more accurately predicted by Monte Carlo-based calculation (ρ=0.95, p<0.0001) vs. convolution-based (ρ=0.80, p=0.0096). This is the first prospective dosimetric comparison of glioma patients clinically treated on both MR-Linac and CBCT-guided Linac. Skin doses were significantly greater with MR-Linac and correlated with in vivo measurements. Future MR-Linac planning processes are being designed to account for skin dosimetry and treatment delivery.

scholarly journals Clinically Delivered Treatment for Glioma Patients on a Hybrid Magnetic Resonance Imaging (MRI)-Linear Accelerator (MR-Linac) and a Cone Beam CT (CBCT)-Guided Linac: Dosimetric Comparisons with In Vivo Skin Dose Correlation

2021 ◽  
Author(s):  
Michael H. Wang ◽  
Anthony Kim ◽  
Mark Ruschin ◽  
Hendrick Tan ◽  
Hany Soliman ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Monte Carlo ◽  
Magnetic Resonance ◽  
Linear Accelerator ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Skin Dose ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

Abstract Background Magnetic Resonance Imaging (MRI)-Linear Accelerator (MR-Linac) radiotherapy requires special consideration for secondary electron interactions within the magnetic field, which can alter dose deposition at air-tissue interfaces. Methods Thirty-seven consecutive glioma patients treated during their radiotherapy course with at least one fraction delivered on MR-Linac or Cone Beam CT (CBCT)-guided Linac, were analyzed. Treatment planning for both systems were completed prior to radiotherapy initiation and approved for clinical delivery using commercial treatment planning systems (TPS): a Monte Carlo calculation-based or convolution calculation-based TPS for MR-Linac or CBCT-Linac, respectively. Dosimetric parameters for planning target volume (PTV), organs-at-risk (OARs), and air-tissue interface were compared. In vivo skin dose during a single fraction of MR-Linac and CBCT-Linac treatment was measured using an Optically Stimulated Luminescent Dosimeter (OSLD) and correlated with TPS skin dose. Results Monte Carlo-based MR-Linac plans and convolution-based CBCT-Linac plans exhibited minimal differences in PTV and OAR parameters. However, MR-Linac plans had greater doses within tissues surrounding air cavities (1.52 Gy higher mean Dmean, p < 0.0001) and skin (1.10 Gy higher mean Dmean, p < 0.0001). In vivo OSLD skin readings were 14.5% greater for MR-Linac treatments (p = 0.0027), and were more accurately predicted by Monte Carlo-based calculation (ρ = 0.95, p < 0.0001) vs. convolution-based (ρ = 0.80, p = 0.0096). Conclusions The magnetic field’s dosimetric impact was minimal for PTV and OARs in glioma as compared to standard CBCT-Linac treatment plans. However, skin doses were significantly greater with the MR-Linac and correlated with in vivo measurements. Future MR-Linac planning processes are being designed to account for skin dosimetry and treatment delivery.

scholarly journals Wykorzystanie obrazowania rezonansem magnetycznym w radioterapii (planowanie leczenia i procedury IGRT) oraz związana z tym rola elektroradiologa

2017 ◽  
Vol 14 (3) ◽  
pp. 69-74
Author(s):  
Elżbieta Czajka
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Cone Beam Ct ◽  
Cone Beam ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

Wykorzystanie rezonansu magnetycznego (ang. magnetic resonance imaging, MRI) w radioterapii jest często poruszanym zagadnieniem w ostatnich latach. Osobny blok wystąpień poświęcony temu tematowi pojawił się również w części programu dedykowanej elektroradiologom na 3rd ESTRO FORUM. Podczas wystąpień omówiono trzy obszary, w których możliwe jest wykorzystanie rezonansu magnetycznego w radioterapii, tj. 1) akwizycja obrazów niezbędnych do planowania leczenia 2) planowanie leczenia w systemie komputerowym w oparciu o obrazowanie rezonansem magnetycznym oraz 3) realizacja leczenia na aparacie terapeutycznym. Zastąpienie w łańcuchu terapeutycznym przede wszystkim tomografii komputerowej (ang. computed tomography, CT) ale również w dalszym etapie innych metod obrazowania, wykorzystujących promieniowanie rentgenowskie np. CBCT (ang. cone beam CT), MVCT (ang. mega voltage CT) lub kVCT (ang. kilo voltage CT) rezonansem magnetycznym, wprowadza do radioterapii tzw. „full-MR workflow”, czyli koncepcję radioterapii opartej wyłącznie o obrazowanie rezonansem magnetycznym. Analiza wybranych doniesień ma na celu przybliżenie czytelnikowi tego zagadnienia, omówienie jego zalet i potencjalnych ograniczeń, ale również umiejscowienie elektroradiologia w całym procesie radioterapeutycznym opartym o rezonans magnetyczny.

scholarly journals Non-invasive diagnostics in fossils - Magnetic Resonance Imaging of pathological belemnites

2005 ◽  
Vol 2 (2) ◽  
pp. 133-140 ◽  
Author(s):  
D. Mietchen ◽  
H. Keupp ◽  
B. Manz ◽  
F. Volke
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Soft Tissue ◽  
Clinical Diagnostics ◽  
Resonance Imaging ◽  
Non Invasive ◽  
Physiological Processes ◽  
Magnetic Resonance Imaging Mri ◽  
Invasive Diagnostics

Abstract. For more than a decade, Magnetic Resonance Imaging (MRI) has been routinely employed in clinical diagnostics because it allows non-invasive studies of anatomical structures and physiological processes in vivo and to differentiate between healthy and pathological states, particularly of soft tissue. Here, we demonstrate that MRI can likewise be applied to fossilized biological samples and help in elucidating paleopathological and paleoecological questions: Five anomalous guards of Jurassic and Cretaceous belemnites are presented along with putative paleopathological diagnoses directly derived from 3D MR images with microscopic resolution. Syn vivo deformities of both the mineralized internal rostrum and the surrounding former soft tissue can be traced back in part to traumatic events of predator-prey-interactions, and partly to parasitism. Besides, evidence is presented that the frequently observed anomalous apical collar might be indicative of an inflammatory disease. These findings highlight the potential of Magnetic Resonance techniques for further paleontological applications.

scholarly journals Perspectives on the Role of Magnetic Resonance Imaging (MRI) for Noninvasive Evaluation of Diabetic Kidney Disease

2021 ◽  
Vol 10 (11) ◽  
pp. 2461
Author(s):  
José María Mora-Gutiérrez ◽  
María A. Fernández-Seara ◽  
Rebeca Echeverria-Chasco ◽  
Nuria Garcia-Fernandez
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Imaging Biomarkers ◽  
Major Advance ◽  
Resonance Imaging ◽  
Diabetic Kidney ◽  
Magnetic Resonance Imaging Mri

Renal magnetic resonance imaging (MRI) techniques are currently in vogue, as they provide in vivo information on renal volume, function, metabolism, perfusion, oxygenation, and microstructural alterations, without the need for exogenous contrast media. New imaging biomarkers can be identified using these tools, which represent a major advance in the understanding and study of the different pathologies affecting the kidney. Diabetic kidney disease (DKD) is one of the most important diseases worldwide due to its high prevalence and impact on public health. However, its multifactorial etiology poses a challenge for both basic and clinical research. Therefore, the use of novel renal MRI techniques is an attractive step forward in the comprehension of DKD, both in its pathogenesis and in its detection and surveillance in the clinical practice. This review article outlines the most promising MRI techniques in the study of DKD, with the purpose of stimulating their clinical translation as possible tools for the diagnosis, follow-up, and monitoring of the clinical impacts of new DKD treatments.

In Vivo MR Studies of Dynamic Changes in the Interosseous Membrane of the Forearm During Rotation

1999 ◽  
Vol 24 (2) ◽  
pp. 245-248 ◽  
Author(s):  
T. NAKAMURA ◽  
Y. YABE ◽  
Y. HORIUCHI
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Interosseous Membrane ◽  
Resonance Imaging ◽  
Forearm Rotation ◽  
Dynamic Changes ◽  
Magnetic Resonance Imaging Mri ◽  
Membranous Part ◽  
The Right

In vivo dynamic changes in the interosseous membrane (IOM) during forearm rotation were studied using magnetic resonance imaging (MRI). The right forearms of 20 healthy volunteers were examined in five different rotational positions. Axial slices were obtained at the proximal quarter, the middle and the distal quarter of the forearm. The changes in shape of the IOM during rotation were observed in an axial MR plane. For each image, we measured the interosseous distance and the length of the interosseous membrane. Images of the tendinous and membranous parts of the IOM could be differentiated by thickness. There were minimal dynamic changes in the tendinous part on the MRI while the membranous part showed numerous changes during rotation. The interosseous distance and the length of the interosseous membrane were maximum from a neutral to a slightly supinated position. The tendinous part is considered to be taut during rotation to provide stability between the radius and the ulna, but the membranous part which is soft, thin and elastic, allows smooth rotation.

Measurement of the Human Cochlear Spiral Curvature In Vivo

2013 ◽  
Vol 284-287 ◽  
pp. 1552-1558
Author(s):  
Jen Fang Yu ◽  
Kun Che Lee
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Inner Ear ◽  
Cochlear Implantation ◽  
Resonance Imaging ◽  
Basal Turn ◽  
Magnetic Resonance Imaging Mri ◽  
Human Inner Ear

This research aims to characterize the geometry of the human cochlear spiral in vivo by measuring curvature and length. Magnetic resonance imaging (MRI) was used to visualise the human inner ear in vivo. The inner ear was imaged in 12 ears in 7 subjects recruited. Visualisation of the cochlear spiral was enhanced by T2 weighting and further processing of the raw images. The spirals were divided into 3 segments: the basal turn segment, the middle turn segment and the apex turn segment. The length and curvature of each segment were measured. The measured lengths of cochlear spiral are consistent with data in the literature derived from anatomical dissections. Overall, the apex turn segment of the cochlear had the greatest degree of curvature. A detailed description of the cochlear spiral is provided, using measurements of curvature and length. This data will provide a valuable reference in the development of cochlear implantation procedures.

scholarly journals Uniform Fe3O4/Gd2O3-DHCA nanocubes for dual-mode magnetic resonance imaging

2020 ◽  
Vol 11 ◽  
pp. 1000-1009
Author(s):  
Miao Qin ◽  
Yueyou Peng ◽  
Mengjie Xu ◽  
Hui Yan ◽  
Yizhu Cheng ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Clinical Diagnostics ◽  
Resonance Imaging ◽  
Dual Mode ◽  
Mri Contrast ◽  
Magnetic Resonance Imaging Mri

The multimodal magnetic resonance imaging (MRI) technique has been extensively studied over the past few years since it offers complementary information that can increase diagnostic accuracy. Simple methods to synthesize contrast agents are necessary for the development of multimodal MRI. Herein, uniformly distributed Fe3O4/Gd2O3 nanocubes for T 1–T 2 dual-mode MRI contrast agents were successfully designed and synthesized. In order to increase hydrophilicity and biocompatibility, the nanocubes were coated with nontoxic 3,4-dihydroxyhydrocinnamic acid (DHCA). The results show that iron (Fe) and gadolinium (Gd) were homogeneously distributed throughout the Fe3O4/Gd2O3-DHCA (FGDA) nanocubes. Relaxation time analysis was performed on the images obtained from the 3.0 T scanner. The results demonstrated that r 1 and r 2 maximum values were 67.57 ± 6.2 and 24.2 ± 1.46 mM−1·s−1, respectively. In vivo T 1- and T 2-weighted images showed that FGDA nanocubes act as a dual-mode contrast agent enhancing MRI quality. Overall, these experimental results suggest that the FGDA nanocubes are interesting tools that can be used to increase MRI quality, enabling accurate clinical diagnostics.

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