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Automatic Frequency Controlled Ramp Procedure

IP.com Disclosure Number: IPCOM000156881D
Original Publication Date: 2007-Aug-25
Included in the Prior Art Database: 2007-Aug-25
Document File: 3 page(s) / 204K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

MR systems should check the frequency with the field plotting device or phantom in the body coil during magnet ramping. If the system detects a signal, the magnet power supply should be controlled via the system and the magnet supervisory in that way that the magnet is ramped to the specified maximum system frequency. The ramp procedure should also work without this function if a problem occurred. This option helps to prevent additional installation time if the magnet field is influenced by the magnetic shield or other environmental conditions.

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Automatic Frequency Controlled Ramp Procedure

Idea: Peter Haeuser, DE-Erlangen

MR systems should check the frequency with the field plotting device or phantom in the body coil during magnet ramping. If the system detects a signal, the magnet power supply should be controlled via the system and the magnet supervisory in that way that the magnet is ramped to the specified maximum system frequency. The ramp procedure should also work without this function if a problem occurred. This option helps to prevent additional installation time if the magnet field is influenced by the magnetic shield or other environmental conditions.

Till now, a MR system is ramped to field according to the magnet factory current specification. This magnet current is measured during final tests in the magnet factory under ideal environmental conditions. The current value is written on the magnet acceptance certificate, which is used for ramping the magnet on customer site. After ramping the magnet, the field will be measured with a field-plotting device together with a part of the RF system. The RF system has a frequency limitation, which reduces the band with of the transmitted and received signal.

If the system frequency could not be found after magnet ramping, an additional external field-plotting device (Gauss meter) has to be used, which covers a bigger frequency and the known current value. A new magnet current can be cal...

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