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In vivo imaging of changes in tumor oxygenation during growth and after treatment
Author(s) -
Bratasz Anna,
Pandian Ramasamy P.,
Deng Yuanmu,
Petryakov Sergey,
Grecula John C.,
Gupta Nilendu,
Kuppusamy Periannan
Publication year - 2007
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.21212
Subject(s) - in vivo , oxygenation , fibrosarcoma , magnetic resonance imaging , irradiation , chemistry , oxygen , electron paramagnetic resonance , biomedical engineering , nuclear medicine , nuclear magnetic resonance , pathology , medicine , radiology , biology , anesthesia , nuclear physics , physics , microbiology and biotechnology , organic chemistry
Abstract A novel procedure for in vivo imaging of the oxygen partial pressure (pO 2 ) in implanted tumors is reported. The procedure uses electron paramagnetic resonance imaging (EPRI) of oxygen‐sensing nanoprobes embedded in the tumor cells. Unlike existing methods of pO 2 quantification, wherein the probes are physically inserted at the time of measurement, the new approach uses cells that are preinternalized (labeled) with the oxygen‐sensing probes, which become permanently embedded in the developed tumor. Radiation‐induced fibrosarcoma (RIF‐1) cells, internalized with nanoprobes of lithium octa‐ n ‐butoxy‐naphthalocyanine (LiNc‐BuO), were allowed to grow as a solid tumor. In vivo imaging of the growing tumor showed a heterogeneous distribution of the spin probe, as well as oxygenation in the tumor volume. The pO 2 images obtained after the tumors were exposed to a single dose of 30‐Gy X‐radiation showed marked redistribution as well as an overall increase in tissue oxygenation, with a maximum increase 6 hr after irradiation. However, larger tumors with a poorly perfused core showed no significant changes in oxygenation. In summary, the use of in vivo EPR technology with embedded oxygen‐sensitive nanoprobes enabled noninvasive visualization of dynamic changes in the intracellular pO 2 of growing and irradiated tumors. Magn Reson Med 57:950–959, 2007. © 2007 Wiley‐Liss, Inc.