Experimental Brain Tumor Response to Hyperthermia Evaluated by in vivo 31P Magnetic Resonance Spectoscopy

In vivo 31P-MR spectroscopy was employed to measure the energy metabolism and pH of T9 gliosarcomas in the flank of Fisher rats before and serially up to 24 h after hyperthermia at various temperatures. Water bath hyperthermia was used to heat tumors at 41℃, 43℃ and 45℃ for 30 min. Following hyperthermia at 41℃ , the ratio of β-nucleoside triphosphate to inorganic phosphate (β-NTP/Pi) significantly decreased at 1 h and 3 h (p<0.05), but recovered at 6 h. The-β-NTP/Pi ratio after hyperthermia at 43℃ and 45℃ decreased significantly up to 24 h (p<0.05). The intracellular pH significantly decreased from the pretreatment level at 6 h after hyperthermia at 45℃. Histological comparison of tumors with and without hyperthermia 24 h posttreatment showed the loss of the endothelial lining and enlargement of the interstitial space in tumors with hyperthermia at 43℃ and 45℃. Thrombosis in vessele and pyknosis were also demonstrated in tumors treated at 43℃ and 45℃. But these changes were more marked in tumors with hyperthermia at 45℃. Our data suggest that in vivo 31P-MR spectroscopy provides useful information about the therapeutic effects of hyperthermia within 6 h after the treatment.

Genetic tolerance

F1 hybrid

Lymphocyte in tolerance

Fast green histone

Semiallogenic graft