Reduction of the 18FDG uptake by the brown fat with the help of propranolol in a difficult case of lymphoma with residual disease suspicion

The oncology group of the French Society of nuclear medicine implemented evaluation criteria of the lymphomas therapy response. The problem often encountered is this one of identification of minimum residual fixations in PET-F.D.G., considered as the residual disease in the non Hodgkin lymphomas. we report the case of a thirty four years old patient treated for diffuse at big B cells non Hodgkin lymphoma, in failure after the first line of treatment and with persistence of a hyper-metabolism in pre and post graft at the level of a para-cardiac residual mass. The post auto graft PET examination showed an important activation of the brown fat, able to question the origin of the residual para-cardiac hyper-metabolism in this dramatic situation, for a young patient and potentially still in therapy failure. In order to reduce the F.D.G. captation by the brown fat, it was proposed a new PET evaluation with propranolol administration (beta blocking) before the tracer injection. The intake of propranolol allowed to reduce in an important way, the F.D.G. captation by the brown fat, without modifying the residual hyper-metabolism. This result is going to lead to the realisation of a surgical biopsy. (N.C.)