The topic of this article is the quantitative and semiquantitative assessment of bone marrow signal alteration in magnetic resonance imaging (MRI) of the lumbar spine in patients with tumor anemia during therapy with epoietin β or placebo. Patients and Methods: We examined 32 patients with head or neck cancer (16 epoietin β, 16 placebo) during radiotherapy in a doubleblind multicenter trial. During radiotherapy, the patients underwent epoietin β therapy for 7-9 weeks. Lumbar spine measurements using T1-w SE, OPP and Turbo- STIR were taken prior to the first epoietin ß or placebo therapy, after the acquired hemoglobin level had been reached, and after the final radiotherapy. The semiquantitative assessment was made blinded by 2 independent radiologists. Results: We found significant differences between both groups. The first MRI showed normal marrow signals. The second MRI revealed a quantified decrease in bone marrow signal in T1-w SE (p < 0.018) and an increase in OPP (p < 0.01) and Turbo-TIR (p < 0.048) sequences. At the third MR imaging, quantified relative marrow signals returned to baseline level in all sequences. Semiquantitative assessment confirmed these results. Conclusion: In both analyses, lumbar spine MRI demonstrates significant bone marrow changes in T1-w SE, OPP and Turbo-STIR sequences during epoietin ß therapy.