Behavior of different nuclear probes for detection of cancer by nuclear magnetic resonance.

A physical explanation is given for the finding that the spin-lattice relaxation time T1, obtained by nuclear magnetic resonance from equivalent malignant and non-malignant samples, is greater for the phosphorus isotype 31P than for the proton 1H. The nuclear relaxation of the phosphorus proceeds by way of its interaction with associated cell water. Within limits determined by other variables, T1 is expected to vary inversely as the square of the gyromagnetic ratio.