NMR in cancer. VII. Sodium-23 magnetic resonance of normal and cancerous tissues.

Sodium-23 magnetic resonance was performed on four types of cancers and six types of normal tissues of rats and mice. The spin-lattice relaxation time of the tumors was generally longer than that of the normal tissues, with the most marked difference occurring between rat liver (T1 = 6.5 msec) and Novikoff hepatoma (T1 =23.7 msec). Estimation of tissue sodium from the signal intensity of the resonance indicated that all four types of tumors contained more sodium than any of the normal tissues.