Spin echo nuclear magnetic resonance in cancerous tissue

Since biological tissues have about 70 or 80% water, the water structure in tissue may be attributed to tissue water. The relaxation time using NMR in cancerous tissue was investigated in various experimental tumors. It was established that for solid tumors in MH134-C3H/He and leukemic mice, the relaxation time (T1and T2) measured by NMR was higher than that of other tissues except brain and lymph node. Moreover, in induced hepatoma and regenerating liver, the value of T2increases in accordance with the malignancy of tumor growth. In another experiment, it was found that protoporphyrin, which has anticancer action without destroying cancer cells at least in vitro, inhibits the increase of T1and T2in solid tumors (MH134-C3H/He) when administered intra-tumor every day. The increase of relaxation time using NMR is considered not only as the increase of motional freedom, but also as the decrease of ordering of tissue water, which has a close connection with disdifferentiation of tissue. Although the clinical application of relaxation time using NMR for differential diagnosis of cancer requires further study, these experimental results suggest that the prolongation of relaxation time may indicate the malignancy of neoplastic growth.