RESUMO
Whole body bone scan with Technetium-99m MDP (methylene diphosphate) can detect bony lesions due to altered osteoblastic activity.Non-physiologic or increased radiotracer uptake in the bony structures of patients with a history of malignant diseases is usually interpreted as being suspicious of bone metastasis. It is extremely important to properly distinguish false positive sites of Tc-99m MDP localization. We present three patients with the same pattern of Tc-99m MDP abnormality in different locations. These scans were all performed on the same day to evaluate possible bone metastases in three patients with breast carcinoma. After careful examination, repeated images revealed bed clothing contamination. This is different from bed contamination by displacement among different patients. It is also different from detector contamination by limited area of involvement where detector contamination appears as a line throughout the total body projection. It can be helpful if a nuclear medicine specialist has a brief look at all scans prior to reporting them. In cases where the same pattern of abnormality is repeated in all images, the possibility of technical error such as bed clothing contamination rather than a pathological abnormality should be borne in mind.
