Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polarized Helium to Image the Lung   The main findings of the european PHIL project (Polarised Helium to Image the
Lung) are reported. State of the art optical pumping techniques for polarising
^3He gas are described. MRI methodological improvements allow dynamical
ventilation images with a good resolution, ultimately limited by gas diffusion.
Diffusion imaging appears as a robust method of lung diagnosis. A discussion of
the potential advantage of low field MRI is presented. Selected PHIL results
for emphysema are given, with the perspectives that this joint work opens up
for the future of respiratory medicine.

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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: econ
16
The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin