title: A magnetic resonance imaging based method for measurement of tissue iron concentration in liver arterially embolized with ferrimagnetic particles designed for magnetic hyperthermia treatment of tumors.
abstract: Rabbit liver was loaded with ferrimagnetic particles of gamma -Fe2 O3 (designed for magnetic hyperthermia treatment of liver tumors) by injecting various doses of a suspension of the particles into the hepatic artery in vivo. Proton transverse relaxation rate (R(2)) images of the livers in vivo, excised, and dissected were generated from a series of single spin-echo images. Mean R(2) values for samples of ferrimagnetic-particle-loaded liver dissected into approximate 1 cm cubes were found to linearly correlate with tissue iron concentration over the range from approximately 0.1 to at least 2.7 mg Fe/g dry tissue when measured at room temperature. Changing the temperature of ferrimagnetic-particle-loaded samples of liver from 1 degrees C to 37 degrees C had no observable effect on tissue R(2) values. However, a small but significant decrease in R(2) was found for control samples containing no ferrimagnetic material on raising the temperature from 1 degrees C to 37 degrees C. Both chemically measured iron concentrations and mean R(2) values for rabbit livers with implanted tumors tended to be higher than those measured for tumor-free liver. This study indicates that tissue R(2) measurement and imaging by nuclear magnetic resonance may have a useful role in magnetic hyperthermia therapy protocols for the treatment of liver cancer.
authors.affiliation: School of Physics, The University of Western Australia, Crawley, WA 6009, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Pardoe
authors.forename: P R
authors.initials: PR
authors.lastname: Clark
authors.forename: T G
authors.initials: TG
authors.lastname: St  Pierre
authors.forename: P
authors.initials: P
authors.lastname: Moroz
authors.forename: S K
authors.initials: SK
authors.lastname: Jones
mesh_terms: D000818:Animals; D004621:Embolization, Therapeutic / Q000379:methods*; D005290:Ferric Compounds / Q000008:administration & dosage*; D006979:Hyperthermia, Induced; D007459:Iodized Oil / Q000008:administration & dosage; D007501:Iron / Q000032:analysis*; D008114:Liver Neoplasms, Experimental / Q000473:pathology* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011817:Rabbits
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D007459:Iodized Oil; D007501:Iron