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Real Time MR Thermometry Using Tm-DOTMA
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作者 Bu S. Park Martin J. Lizak +1 位作者 Leonardo M. Angelone Sunder S. Rajan 《Journal of Electromagnetic Analysis and Applications》 2015年第4期115-125,共11页
We present results of real-time and sensitive MR Thermometry (MRT) using a paramagnetic lanthanide complex thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraa-cetate (Tm-DOTMA) to study radio f... We present results of real-time and sensitive MR Thermometry (MRT) using a paramagnetic lanthanide complex thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraa-cetate (Tm-DOTMA) to study radio frequency (RF) heating induced by a copper wire and a titanium bone screw in an agarose gel phantom. The temperature dependent chemical shift coefficient (TDCSC) of the methyl resonance was found to be 0.7 ± 0.03 ppm/°;C in agarose gel. The methyl protons of Tm-DOTMA were imaged using 2D chemical shift imaging (CSI) and 3D phase mapping methods (PMM), approximately 7 sec long, and compared with conventional water proton resonance frequency (PRF) method. Two RF-induced heating approaches were tested: 1) using a prescan before the MRT;or 2) using the heating caused by the imaging pulse during continuous imaging. Both approaches allowed detection of temperature changes which are less than 1°;C and continuously mapping temperature changes around the copper wire. Using a heating pre-scan, the Tm-DOTMA 2D-CSI allowed better qualitative visualization of the temperature changes around the titanium screw compared with water phase shift thermometry. Numerical electromagnetic field simulations were also conducted for the evaluation of orientation dependency using the copper wire in 4.7 T (200 MHz). Thermometry approach using Tm-DOTMA can detect smaller temperature changes with decreased scanning time resulting in real-time and sensitive temperature mapping. 展开更多
关键词 Tm-DOTMA CSI PRF Real-Time FDTD RF Temperature MAPPING
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Four-dimensional light shaping: manipulating ultrafast spatiotemporal foci in space and time 被引量:1
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作者 Bangshan Sun Patrick S Salter +5 位作者 Clemens Roider Alexander Jesacher Johannes Strauss Johannes Heberle Michael Schmidt Martin J Booth 《Light(Science & Applications)》 SCIE EI CAS CSCD 2017年第1期293-299,共7页
The spectral dispersion of ultrashort pulses allows the simultaneous focusing of light in both space and time,which creates socalled spatiotemporal foci.Such space–time coupling may be combined with the existing holo... The spectral dispersion of ultrashort pulses allows the simultaneous focusing of light in both space and time,which creates socalled spatiotemporal foci.Such space–time coupling may be combined with the existing holographic techniques to give a further dimension of control when generating focal light fields.In the present study,it is shown that a phase-only hologram placed in the pupil plane of an objective and illuminated by a spatially chirped ultrashort pulse can be used to generate threedimensional arrays of spatio-temporally focused spots.By exploiting the pulse front tilt generated at focus when applying simultaneous spatial and temporal focusing(SSTF),it is possible to overlap neighboring foci in time to create a smooth intensity distribution.The resulting light field displays a high level of axial confinement,with experimental demonstrations given through two-photon microscopy and the non-linear laser fabrication of glass. 展开更多
关键词 laser material processing light shaping spatiotemporal focusing ultrafast lasers
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