Detection of early gamma-postirradiation effects in murine spleen by proton NMR relaxation times

Background: It was our aim to evaluate the potential of proton relaxation t imes for the early detection of radiation-induced spleen changes. Materials and Methods: Female Swiss mice were irradiated with doses ranging from 0.0 5 Gy to 4 Gy. The body weight, the spleen weight and the spleen water conte nt of single animals were determined. Measurements of longitudinal (TI) and transversal (T2) proton relaxation times of the spleen samples were perfor med in a 0.47 T spectrometer. Histological examinations of the control and irradiated organs were performed. Results: NMR measurements during the firs t five days after irradiation showed that total body gamma -irradiation wit h doses from 1.5 Gy to 4 Gy results in decreasing T1 of the murine spleen. Significant shortening in T2 was observed for the spleen of animals irradia ted with a dose of 4 Gy. Histological examinations demonstrated subnormal a rchitecture in slices derived from animals irradiated with 2 Gy and 4 Gy. C onclusion: The fluctuations of the spleen TI and T2 of irradiated mice are correlated with relative spleen weight and can be used to estimate radiatio n induced changes in this organ.