Discriminating Hepatocellular Carcinoma in Rats Using a High-T_c SQUID Detected Nuclear Resonance Spectrometer in a Magnetic Shielding Box

In this study, we report the spin-lattice relaxation rate of hepatocellular carcinoma (HCC) and normal liver tissue in rats using a high-T_c superconducting quantum interference device (SQUID) based nuclear magnetic resonance (NMR) spectrometer. The resonance spectrometer used for discriminating liver tumors in rats via the difference in longitudinal relaxation time in low magnetic fields was set up in a compact and portable magnetic shielding box. The frequency-domain NMR signals of HCC tissues and normal liver tissues were analyzed to study their respective longitudinal relaxation rate T₁^-1. The T₁^-1 of liver tissues for ten normal rats and ten cancerous rats were investigated respectively. The averaged T₁^-1 value of normal liver tissue was (6.41±0.66) s^-1, and the averaged T₁^-1 value of cancerous tissue was (3.38±0.15) s^-1. The ratio of T₁^-1 for normal liver tissues and cancerous liver tissues of the rats investigated is estimated to be 1.9. Since this significant statistical difference, the T₁^-1 value can be used to distinguish the HCC tissues from normal liver tissues. This method of examining liver and tumor tissues has the advantages of being convenient, easy to operate, and stable.