title: Changes in 31P nuclear magnetic resonance with tumor growth in radioresistant and radiosensitive tumors.
abstract: In vivo 31P nuclear magnetic resonance (31P NMR) spectroscopy has been used to compare metabolic profiles with tumor radiosensitivity. A radioresistant mammary carcinoma (MCa) and a radiosensitive methylcholanthrene-induced fibrosarcoma (Meth-A) were studied by 31P NMR spectroscopy in the tumor volume range of approximately 100-1200 mm3. The MCa showed a constant pH in this volume range; the ratio of phosphocreatine to inorganic phosphate (PCr/Pi) for 160-300 mm3 tumors was 0.33 +/- 0.11 (mean +/- standard deviation) and did not change (0.29 +/- .09) for tumors in the volume range of 600-1200 mm3. In comparison, the Meth-A showed a decrease in tumor pH as volume increased from 160-300 mm3 (pH 7.16 +/- 0.4) to 600-1200 mm3 (pH 6.94 +/- .07). Tumor PCr/Pi decreased from 0.70 +/- .16 (160-300 mm3) to 0.33 +/- .16 (600-1200 mm3). The radiation doses for control of MCa-induced tumors in 50% of the treated tumors ranged from 65 (150-250 mm3) to 71 Gy (1000-1300 mm3) and for the Meth-A-induced tumors ranged from 35 (150-250 mm3) to 38 Gy (1000-1300 mm3). These results suggest that 31P NMR spectra may be a qualitative predictor of tumor hypoxia, although further studies of human and rodent tumors are necessary to support this hypothesis.
authors.affiliation: Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
authors.forename: J A
authors.initials: JA
authors.lastname: Koutcher
authors.forename: A A
authors.initials: AA
authors.lastname: Alfieri
authors.forename: D C
authors.initials: DC
authors.lastname: Barnett
authors.forename: D C
authors.initials: DC
authors.lastname: Cowburn
authors.forename: A B
authors.initials: AB
authors.lastname: Kornblith
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000818:Animals; D005354:Fibrosarcoma / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D008748:Methylcholanthrene; D051379:Mice; D009368:Neoplasm Transplantation; D009711:Nucleotides / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D011836:Radiation Tolerance
chemical_list: D009711:Nucleotides; D010725:Phosphocreatine; D008748:Methylcholanthrene