Dr Behrens trained in diagnostic radiology at the University of Caracas, in his home country of Venezuela. He completed a surgery internship at Rush University Medical Center in Chicago, then a year of fellowship in interventional radiology at Rush. He is Board certified in radiology by the ABR.

Dr Behrens is trained in interventional oncology (image guided treatment of cancer), and has a particular interest in non-surgical treatment of liver disease. He has done research in non-surgical treatment of portal hypertension during his fellowship. He has been the author of numerous research papers and book chapters on liver disease, arterial disease, and venous conditions.