The invention relates to combination comprising a pharmaceutically acceptable preparation of a compound of formula (I), or a pharmaceutically acceptable salt thereof, and a gallium and its use in diagnosis. The invention also pertains to the use of a compound of formula I or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for the treatment of an excess iron overload in the human or animal body whereby said body is undergoing gallium scintigraphy and whereby the treatment removing said excess of iron is interrupted for a period of 2 to 10 days prior to the gallium scintigraphy and resumed after the gallium scintigraphy readings.