Extraosseous uptake with DPD (Teceos(®))

During a short period of 10 days, four patients presented with intense extraosseous uptake of a technetium-labelled bone-seeking agent, three in the heart and one in the liver at our hospital. During the next 6 weeks, identical heart uptake was found in another two patients. Two patients were re-examined, with identical uptake on the second occasion. A search for a possible cause was initiated.

Bone scintigraphy with Teceos(®) was performed after labelling the kit as described in the Summary of Product Characteristics [IBA, http://www.iba-molecular.com/sites/default/files/spcT1901E.pdf (in french, 29/3/2011)]. On two occasions, the kit used was retrospectively analysed, without any apparent abnormality. Two patients were re-examined 1 month later, with identical cardiac and liver uptake on repeat examination. Contact with referring physicians and blood test screening did not show any consistent reason for these extraosseous uptakes. Additionally, five cases at other hospitals in Norway have been brought to our attention.

In at least ten patients, intense cardiac uptake has been recorded, all in relatively old patients, and one young patient had massive liver uptake. No abnormalities in labelling or composition of 3,3-diphospho-1,2-propanedicarboxylic acid were found.

Liver and cardiac uptakes of bone-seeking agents have been described in amyloidosis, and for the heart, after myocardial infarction. We have ruled out any possible contamination by interfering radiopharmaceuticals and cannot find any reason for these findings. Eleven patients with amyloidosis seem one of several hypotheses that is highly improbable.