Optimization and batch production of DTPA-labelled antibody kits for routine use in 111In immunoscintigraphy

A procedure for conjugating antibodies in batches with DTPA is described which yields pharmaceutical grade preparations that can be kept in frozen storage until required. Routine radiolabelling is then simply performed by adding 111In chloride to the sterile 'kit' vial. After 1h, a DTPA solution is added to make the preparation ready for use in patients. The effects of pH, DTPA to antibody ratio, and time of reaction were investigated to optimize the preparation. By this method the antibody-DTPA conjugates may be prepared and the quality control performed at regional nuclear medicine centres where facilities and expertise already exist. These 'kits' can then be distributed to other departments where the 111In is added as and when required in a similar way to the preparation of other radiopharmaceuticals.