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.

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.

[1]  T. S. St. Pierre,et al.  Arterial embolization hyperthermia: hepatic iron particle distribution and its potential determination by magnetic resonance imaging. , 2002, Physics in medicine and biology.

[2]  S. Kasaoka,et al.  Tumor regression by inductive hyperthermia combined with hepatic embolization using dextran magnetite-incorporated microspheres in rats. , 2000, International journal of oncology.

[3]  B. Gray,et al.  Internal radiotherapy for hepatic metastases II: The blood supply to hepatic metastases. , 1983, The Journal of surgical research.

[4]  B. Gray,et al.  Comparison of portal vein chemotherapy with hepatic artery chemotherapy in the treatment of liver micrometastases. , 1990, American journal of surgery.

[5]  C. Breedis,et al.  The blood supply of neoplasms in the liver. , 1954, The American journal of pathology.

[6]  J. Bulte,et al.  Relaxometry, magnetometry, and EPR evidence for three magnetic phases in the MR contrast agent MION-46L , 1999 .

[7]  P. Moroz,et al.  The effect of tumour size on ferromagnetic embolization hyperthermia in a rabbit liver tumour model , 2002, International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group.

[8]  Y. Nishimura,et al.  Targeted hyperthermia using dextran magnetite complex: a new treatment modality for liver tumors. , 1996, Hepato-gastroenterology.

[9]  T. S. St. Pierre,et al.  Quantitative mapping of transverse relaxivity (1/T(2)) in hepatic iron overload: a single spin-echo imaging methodology. , 2000, Magnetic resonance imaging.

[10]  J. Glasel.  Nuclear Magnetic Resonance Studies on Water and Ice , 1972 .

[11]  P. Moroz,et al.  Arterial embolization hyperthermia in porcine renal tissue. , 2002, The Journal of surgical research.

[12]  Urs O. Häfeli,et al.  Scientific and clinical applications of magnetic carriers , 1997 .

[13]  P. Moroz,et al.  Tumor response to arterial embolization hyperthermia and direct injection hyperthermia in a rabbit liver tumor model , 2002, Journal of surgical oncology.

[14]  P. Moroz,et al.  Targeting liver tumors with hyperthermia: Ferromagnetic embolization in a rabbit liver tumor model , 2001, Journal of surgical oncology.

[15]  B. Gray,et al.  Treatment of experimental rabbit liver tumours by selectively targeted hyperthermia , 2002, International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group.

[16]  B. Gray,et al.  Vascularization of small liver metastases , 1989, The British journal of surgery.

[17]  J A Frank,et al.  Frequency dependence of MR relaxation times II. Iron oxides , 1993, Journal of magnetic resonance imaging : JMRI.