Sj. Li et al., CORRELATION OF RADIOBIOLOGICAL ASSAYS OF HYPOXIC FRACTION WITH P-31 MAGNETIC-RESONANCE SPECTROSCOPY ACROSS MULTIPLE TUMOR LINES, Radiation research, 143(1), 1995, pp. 45-53
Hypoxic fractions were measured in multiple tumor models and compared
to P-31 magnetic resonance spectroscopy (MRS) parameters. Hypoxic frac
tions were measured by excision assays in intramuscular and subcutaneo
us RIF-1 tumors, large and small SCCVII tumors, and KHT tumors. The hy
poxic fractions ranged from 3% (small SCCVII) to 21% (KHT). Measuremen
ts of P-31 MRS parameters (indices of tumor metabolism) were made unde
r 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 h
ypoxic 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 f
ractions across different tumor lines that can be applied non-invasive
ly to individual tumors. (C) 1995 by Radiation Research Society