[MR study of bone marrow changes of the spine following radiotherapy].

MR examinations of bone marrow variations in the spine after radiotherapy were performed on 24 patients in the thoracic and lumbar vertebral column. The actinically affected bone marrow showed a characteristic increase of signal intensity in T1-weighted sequences in the sagittal plane, due to conversion of red marrow to fatty marrow. The dose in the well-defined radiation areas was between 28 and 70 Gray (Gy). The lowest dose, applied to the bone-marrow bordering on the defined radiation areas, where we still could find an increase of signal intensity, was below 2.6 to 5 Gy. MR imaging was performed between 6 and 9 month after radiotherapy.