Small-Animal RF Modules

Simple-tune Pre-Clinical Research RF
Imaging Modules

Small-Animal Litz or Litzcage Modules
MRI coils with best sensitivity, homogeneity, and convenience.

Some have thought that Doty Litz or Litzcage coils are made with litz wire.  That is not the case.  An old meaning of the word litz is woven.  The coils, with the Doty patented insulated crossovers, can be thought of as “woven” coils.

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Standard products include 1H rf coils as well as dual-frequency coils.
Custom coils are also available.

Easy tuning                   

Mouse Coils – Rat Coils – Rabbit Coils – Primate Head Coils

A unique symmetrizing circuit ensures the coil is easily tuned and matched to the full range of samples with negligible loss in efficiency, channel separation, or symmetry.  The tuning range is much better than with conventional birdcages and tuning methods.

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Robust Design

Versatile, Robust Design
In Doty Imaging Modules, the rf Litz or Litzcage coils are enclosed in the rf shield and packaged in an integrated aesthetic cover. Coil dimensions are customized to your specifications.

Exceptional Sensitivity

The linear Litz or CP (circular polarization) Quadrature Litzcage coils have SNR 10-15% higher than with conventional linear or quadrature birdcages of similar dimensions  – and often much better. The B1 homogeneity is 10-30% better and the coils have improved B0 homogeneity.  Simple-tune Litz coils can be easily double-tuned.

Doty RF Litz  or Litzcage Coil Modules

You wouldn’t consider buying something like a computer or spectrum analyzer without reviewing and comparing detailed specifica­tions.  You owe it to yourself to apply the same critical standards when purchasing an rf coil.  With rf coils, the most important criteria usually are S/N, B1 homogeneity, and reliability.  For S/N, simply check the 90° pulse spec.  Regardless of whether it’s single or double resonance, shielded or unshielded, linear or circular polarization, short or long, surface or volume, one simple relationship always holds for a given voxel size and other conditions:

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where τ90 is the   90° pulse length (we specify for a hard pulse) and P is the transmitter power. Many of the smaller coils listed in the tables have S/N better by factors of 1.5 to 3 than published birdcages of similar size and tuning. Our 1H Litzcages have truly extraordinary robustnesss, ease-of-use with widely differing samples, homogeneity, and S/N.

Does your τ90 drop by less than a factor of two (at constant P ) when your sample diameter drops by a factor of 2?  Do you have difficulty matching and tuning with certain samples?  Are you tired of tweaking numerous adjustments to try to get acceptable B1 homogeneity with your samples? If you answered yes to any of the above, you should inquire whether a Doty Litz or Litzcage  coil could improve your results.

With all the improvements, customers are often surprised that there is usually a substantial cost advantage in choosing Doty coils.

Check for coil specifications in the tables below.



Downloadable Documents

Download a preprint of “RF Coil Technology for Small-Animal MRI”, by F. David Doty, George Entzminger, Jatin Kulkarni, Kranti Pamarthy and John P. Staab, published in [NMR Biomed. 2007; 20: 304-325, published online in Wiley Interscience, at http://www.interscience.wiley.com, DOI: 10.1002/nbm.1149].

Presented at ISMRM 2005

Images

Mouse Brain Images

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This T2 spin-echo experiment on a live mouse brain using a 2 cm linear Litz coil in a 4.7 T horizontal magnet demonstrated substantially better B1 homogeneity and better S/N than a quadrature birdcage of similar dimensions. The Litz coil easily tuned and matched to any load in less than a minute.

Images courtesy of Dr. Joel R. Garbow, Washington University, St. Louis, MO.

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