Amine modified dextran is labeled with mannose molecules as well as tin-117m. This tin-117m labeled mannose modified dextran is useful in treating maladies that express CD206, in particular rheumatoid arthritis, as well as the cancer typically located in the lymph nodes. This provides a systemic treatment for such maladies. The tin-117m will destroy cells to which it is bonded and also can be imaged. Further, due to the nature of the radiation from the tin-117m, it does not do significant damage to nearby healthy cells.