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TUNING COILS WITHOUT VARIABLE CAPACITORS OR INDUCTORS

IP.com Disclosure Number: IPCOM000242859D
Publication Date: 2015-Aug-26
Document File: 4 page(s) / 228K

Publishing Venue

The IP.com Prior Art Database

Abstract

The disclosure includes a technique for tuning radiofrequency (RF) coil uniformly and easily. The technique tunes RF coil without using capacitors or inductors in a RF probe. The technique utilizes RF tuners (RFTs) for tuning the RF coil to a resonant frequency very easily and in a very short amount of time. RFTs are small copper strips or semi circular strips which can be easily inserted into pockets of the RF coil for final tuning of the RF coil.

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TUNING COILS WITHOUT VARIABLE CAPACITORS OR INDUCTORS

BACKGROUND

The present disclosure relates generally to radiofrequency (RF) coils used in a medical resonance imaging (MRI) system and more particularly to a technique for tuning RF coils uniformly and easily.

Generally, variations in size and tissue composition of an anatomy placed in an imaging coil affect amount of radiofrequency (RF) energy penetrating and the amount of signal detected from the imaged anatomy. Accordingly, the RF coil needs to be tuned. The RF coil is tuned by adjusting capacitors on an RF probe, referred to as chip capacitors. However, tuning the RF coil by adjusting the chip capacitors is a very tedious and time consuming activity. Also, determining the right chip capacitor value and tuning the RF coil exactly to the resonant frequency is sometimes extremely difficult.

In one conventional technique, variable capacitors or inductors are used to tune the RF coil. However, the conventional technique requires the RF coil to be taken out for soldering the capacitors. Also, variable capacitors are expensive, bulky and less reliable.

It would be desirable to have an improved technique to tune RF coils uniformly and easily.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 depicts a simulation of a hybrid birdcage coil with radiofrequency tuners (RFTs).

Figure 2 depicts placement of RFTs outside the hybrid birdcage coil in-between a copper antenna and a shield.

Figure 3 depicts a process of replacing variable capacitors with copper strips as RFTs in a coil design.

DETAILED DESCRIPTION

The disclosure includes a technique for tuning radiofrequency (RF) coil of a magnetic resonance (MRI) system uniformly and easily. The technique tunes RF coil without using capacitors or inductors in an RF probe. The technique utilizes RF tuners (RFTs) for tuning the RF coil to a resonant frequency very easily and in a very short amount of time. Moreover, RFTs can be used while the RF coil is inside a gradient coil or inside a magnet when the magnet is fully ramped.

RFTs are small copper strips or semi circular strips which can be easily inserted into pockets of the RF coil for final tuning of the RF coil. The technique maintains a higher rough tune frequency with the fixed capacitors than a desired frequency of operation. The technique can also be applied to a hybrid birdcage coil.

Figure 1 depicts a simulation of a hybri...