Abstract: Angiographic dye is used in multiple diagnostic and therapeutic procedures. These procedures have a very high accuracy of diagnostic and therapeutic abilities but have potential nephrotoxicity. This patent relates to (i) an improvement in angiography therapy technology using a Nanomagnetic modification of angiography contrast dye and (ii) a novel process for its removal using intravascular catheter based electromagnet system. This patent also relates to in-laboratory and/or in-house modification of the existing radiocontrast dye using various methods for making it amenable to manipulation and/or extraction off the blood stream, by the catheter based electro magnet system as described in the present invention. This patent also relates to the process of reno-protection from potentially nephrotoxic contrast dye by its electromagnetic removal and its use thereof.