Effects of local irradiation on spin-lattice relaxation time of phosphate metabolites in mouse tumors monitored by 31P magnetic resonance spectroscopy.
An inversion-recovery pulse sequence and solenoidal surface coil were employed to determine the spin-lattice relaxation time (T1) in murine tumors (RIF-1 and SCCVII). Reduction in T1s of inorganic phosphate (Pi) and nucleotide triphosphates (NTP) has been observed in irradiated tumors compared with unirradiated tumors. The reduction is accompanied by tumor regression and improved tumor energetic status in both tumor lines. The results of the T1 measurement of phosphate metabolites in tumors suggest that partial saturation effects may exist in spectra and could effect quantitative analysis when short repetition time is used. The reduction in T1s of Pi and NTP may be attributed to the active biochemical exchange and better tumor oxygenation in irradiated tumors.
Li
S J
SJ
Department of Radiology, Medical College of Wisconsin, Milwaukee 53226.
Jin
G Y
GY
Moulder
J E
JE
D000818:Animals; D003037:Cobalt Radioisotopes / Q000627:therapeutic use; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000532:radiotherapy*; D010710:Phosphates / Q000378:metabolism*; D011867:Radioisotope Teletherapy
D003037:Cobalt Radioisotopes; D010710:Phosphates