• Registrar in Urology, General Hospital of Athens “G.Gennimatas”(2000-2005)
• Registrar in General Surgery, General Hospital of Rhodes 1st surgical department (1999-2000)
• Scientific partner, General Hospital of Rhodes 1st surgical department (1995-1996)
• Graduated from Medical School,U.M.F.CLUJ, Napoka (1987-1994)

Clinical and Research interest:

• Minimally invasive and endoscopic surgical urology 
• Urinary lithiasis , Laser lithotripsy, Extracorporeal lithotripsy
• Prostate hyperplasia,(TURIS Prostatectomy)
• Uro-Oncology ( Prostate,Testicular,Kindneys,Urinary bladder Cancer)
• Pediatric urology
• Neuro –Urology (Urodynamics)
• Andrology-Male Infertility
• Female Urology
• Incontinence
• Reconstructive Urolology 

• Doctoral Degree from Athens Medical School. Title of Thesis: “Study of the cell proliferation and apoptosis markers in the prostate adenoma in relation to the obesity index”
• Advanced Trauma Life Support (ATLS) Hellenic National Center ,American College of Surgeons ,University of Patra Medical School Dep.of Surgery (2002)
• European Board of Urology-In Service Examination /Assessment 2001-2002
• Training in Minimal Access Surgery IRCAD-EITS, Louis Pasteur University .Strasbourg ,France (2008)

• Member of the Hellenic Urological Association (2005-present)
• Fellow of the European Association of Urology (FEBU) (2002-present)
• Member of the Endourological Society(2002-present)
• Member of Medical Association of Athens

• Kalantzis A. “Overactive bladder” Athens 2004. ISBN960-360-216-4
• Kalantzis A. “Peyronie Disease from Vesalius and Fallopio till today”Athens 2005.ISBN 960-630-536-8
• Translation-Editing of 5 medical books 
• Authored over 100 publications, conducts and participates in advanced continuing medical education (CME) activities

He has published over 30 scholarly articles,in magazines (tirage > 100.000 copies)