東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Electromagnet control and efficient ...

Matter, Nathaniel Ivan.

Linked to FindBook

Google Book

Amazon

博客來

Electromagnet control and efficient imaging in prepolarized MRI.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Electromagnet control and efficient imaging in prepolarized MRI./
Author:	Matter, Nathaniel Ivan.
Description:	127 p.
Notes:	Adviser: Albert Macovski.
Contained By:	Dissertation Abstracts International67-05B.
Subject:	Engineering, Electronics and Electrical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3219334
ISBN:	9780542707698

Electromagnet control and efficient imaging in prepolarized MRI.
Matter, Nathaniel Ivan.

Electromagnet control and efficient imaging in prepolarized MRI. - 127 p.

Adviser: Albert Macovski.

Thesis (Ph.D.)--Stanford University, 2006.

Magnetic resonance imaging (MRI) uses magnetic fields to acquire cross-sectional medical images with a rich variety of contrast methods for identifying pathology in the body, all without ionizing radiation or other harmful side effects. Prepolarized magnetic resonance imaging (PMRI) uses a fundamentally different magnet architecture than conventional MRI to take advantage of the benefits of acquiring image data at a low magnetic field while achieving the better signal-to-noise ratio of a high magnetic field. Whereas a conventional MRI scanner uses a static background magnetic field generated with superconducting coils or a permanent magnet, a PMRI scanner uses two independently pulsed copper electromagnets.

ISBN: 9780542707698Subjects--Topical Terms:

626636
Engineering, Electronics and Electrical.

Electromagnet control and efficient imaging in prepolarized MRI.
LDR:03183nam 2200313 a 45 001 954361
005 20110622
008 110622s2006 eng d
020 $a 9780542707698
035 $a (UMI)AAI3219334
035 $a AAI3219334
040 $a UMI $c UMI
100 1 $a Matter, Nathaniel Ivan. $3 1277832
245 1 0 $a Electromagnet control and efficient imaging in prepolarized MRI.
300 $a 127 p.
500 $a Adviser: Albert Macovski.
500 $a Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2751.
502 $a Thesis (Ph.D.)--Stanford University, 2006.
520 $a Magnetic resonance imaging (MRI) uses magnetic fields to acquire cross-sectional medical images with a rich variety of contrast methods for identifying pathology in the body, all without ionizing radiation or other harmful side effects. Prepolarized magnetic resonance imaging (PMRI) uses a fundamentally different magnet architecture than conventional MRI to take advantage of the benefits of acquiring image data at a low magnetic field while achieving the better signal-to-noise ratio of a high magnetic field. Whereas a conventional MRI scanner uses a static background magnetic field generated with superconducting coils or a permanent magnet, a PMRI scanner uses two independently pulsed copper electromagnets.
520 $a The primary advantages of PMRI include the ability to image adjacent to metal prostheses in the body, lower scanner cost, and the possibility for novel contrast mechanisms that require a variable magnetic field. These benefits come at the cost of limited flexibility, however PMRI can perform standard clinical musculoskeletal imaging with almost the same efficiency as conventional MRI.
520 $a This work addressed three engineering challenges in PMRI: design of the pulsing electronics for the polarizing magnet, design of the control system for the readout magnet, and design of efficient imaging methods. The high-field polarizing magnet was rapidly pulsed with a capacitor storage system but required a leakage current bypass network to minimize current in the off state. The low-field readout magnet was powered with a precise control system that offered both maximum regulation and optimal system damping to minimize transient switching disturbances. Even with optimal magnet control, the residual field errors can cause significant imaging artifacts unless the system RF transmit and receive are properly phase shifted with either software or hardware solutions.
520 $a Through improved design of the magnet electronics and the successful implementation of fast 3D imaging sequences, the Stanford PMRI system can now achieve standard clinical contrast and resolution for imaging in vivo human wrists. Additional upgrades to the PMRI system will bring the image SNR closer to that of clinical scanners, but PMRI already outperforms MRI in the presence of metal.
590 $a School code: 0212.
650 4 $a Engineering, Electronics and Electrical. $3 626636
650 4 $a Health Sciences, Radiology. $3 1019076
690 $a 0544
690 $a 0574
710 2 $a Stanford University. $3 754827
773 0 $t Dissertation Abstracts International $g 67-05B.
790 $a 0212
790 1 0 $a Macovski, Albert, $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3219334