CORRELATION OF RADIOBIOLOGICAL ASSAYS OF HYPOXIC FRACTION WITH PHOSPHORUS-31 MAGNETIC RESONANCE SPECTROSCOPY ACROSS MULTIPLE TUMOR LINES

摘要

Hypoxic fractions were measured in multiple tumor models and compared to P-31 magnetic resonance spectroscopy (MRS) parameters. Hypoxic fractions were measured by excision assays in intramuscular and subcutaneous RIF-1 tumors, large and small SCCVII tumors, and KHT tumors. The hypoxic fractions ranged from 3% (small SCCVII) to 21% (KHT). Measurements of P-31 MRS parameters (indices of tumor metabolism) were made under the same conditions used in the hypoxic fraction assays. The PCr/P-i ratios in the five tumor models were strongly correlated (r(2) = 0.98, tau = 1.00, P < 0.02) with their hypoxic fractions, and the NTP/P-i ratio was weakly correlated (r(2) = 0.67, tau = 0.60, P < 0.17) with hypoxic fraction. Smaller values of the PCr/P-i and NTP/P-i ratios were found in the tumors with larger hypoxic fractions. These experiments indicate that P-31 MRS may provide a relative measurement of hypoxic fractions across different tumor lines that can be applied non-invasively to individual tumors. (C) 1995 by Radiation Research Society [References: 42]