In vivo NMR relaxation studies of tumors

Pulsed nuclear magnetic resonance has been used to differentiate between normal mouse tail tissue and a malignant transplanted melanoma S91 located on the tail of a live mouse. Measurements of proton spin-lattice and spin-spin relaxation serve to detect and monitor the tumor growth. The mature tumor exhibits a spin-lattice relaxation time T1of s contrasting with the corresponding normal tail tissue T1of half this value. On the other hand spin-spin relaxation in normal tissue cannot be characterized by a single relaxation time T2. The corresponding relaxation in a mature tumor is found to be closer to a single exponential but still requires at least two superimposed exponential decays.