0000000000612082

AUTHOR

Johannes T. Heverhagen

0000-0002-5416-6650

showing 3 related works from this author

Multicenter, double-blind, randomized, intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for Breast MR ima…

2011

To intraindividually compare 0.1 mmol/kg doses of gadobenate dimeglumine and gadopentetate dimeglumine for contrast material-enhanced breast magnetic resonance (MR) imaging by using a prospective, multicenter double-blind, randomized protocol.Institutional review board approval and patient informed consent were obtained. One hundred sixty-two women (mean age, 52.8 years ± 12.3 [standard deviation]) enrolled at 17 sites in Europe and China between July 2007 and May 2009 underwent at least one breast MR imaging examination at 1.5 T by using three-dimensional spoiled gradient-echo sequences. Of these, 151 women received both contrast agents in randomized order in otherwise identical examinatio…

AdultGadolinium DTPAChinaContrast MediaBreast NeoplasmsSensitivity and Specificitylaw.inventionDouble blindbreast neoplasm contrast media MRIBreast cancerMegluminebreast neoplasmRandomized controlled trialDouble-Blind MethodlawPredictive Value of TestsImage Interpretation Computer-AssistedmedicineOrganometallic CompoundsHumansRadiology Nuclear Medicine and imagingProspective StudiesProspective cohort studyGADOBENATE DIMEGLUMINEAgedAged 80 and overChi-Square DistributionCross-Over Studiesbusiness.industryMiddle Agedmedicine.diseaseMr imagingCrossover studyMagnetic Resonance ImagingEuropeFemaleBreast diseaseNuclear medicinebusinessMRIRadiology
researchProduct

A 20-channel receive-only mouse array coil for a 3 T clinical MRI system

2011

A 20-channel phased-array coil for MRI of mice has been designed, constructed, and validated with bench measurements and high-resolution accelerated imaging. The technical challenges of designing a small, high density array have been overcome using individual small-diameter coil elements arranged on a cylinder in a hexagonal overlapping design with adjacent low impedance preamplifiers to further decouple the array elements. Signal-to-noise ratio (SNR) and noise amplification in accelerated imaging were simulated and quantitatively evaluated in phantoms and in vivo mouse images. Comparison between the 20-channel mouse array and a length-matched quadrature driven small animal birdcage coil sh…

Physicsmedicine.diagnostic_testPreamplifierPhysics::Medical PhysicsWhole body imagingMagnetic resonance imagingequipment and suppliesLow impedanceImaging phantomTransducerNuclear magnetic resonanceElectromagnetic coilArray coilmedicineRadiology Nuclear Medicine and imagingBiomedical engineeringMagnetic Resonance in Medicine
researchProduct

Investigation of correction factors for non-reference conditions in ion chamber photon dosimetry with Monte-Carlo simulations.

2009

Current dosimetry protocols require geometrical reference conditions for the determination of absorbed dose in external radiotherapy. Whenever these geometrical conditions cannot be maintained the application of additional corrections becomes necessary, in principle. The current DIN6800-2 protocol includes a corresponding factor k(NR), but numerical values are lacking and no definite information about the magnitude of this correction is available yet. This study presents Monte-Carlo based calculations within the 6 MV-X photon field of a linear accelerator for a common used ion chamber (PTW31010) employing the EGSnrc code system. The linear accelerator model was matched to measurements, show…

PhotonMonte Carlo methodBiophysicsRadiation DosageLinear particle acceleratorlaw.inventionIonlawDosimetryHumansScattering RadiationRadiology Nuclear Medicine and imagingPhysicsIonsPhotonsRadiological and Ultrasound TechnologyPhantoms ImagingRadiotherapy Planning Computer-AssistedReproducibility of ResultsWaterParticle acceleratorCharged particleIonization chamberRadiotherapy Intensity-ModulatedAtomic physicsParticle AcceleratorsMonte Carlo MethodAlgorithmsZeitschrift fur medizinische Physik
researchProduct