Dr. Theodoros Tsionis was born and raised in Serres, Greece. He completed his medical studies at the Medical School of Democritus University of Thrace. Following graduation, he commenced his specialty training in Internal Medicine at the General Hospital of Serres. Seeking to broaden his personal and professional horizons, he subsequently continued his specialization in Gastroenterology, together with his brother, at the GRN Clinic in Schwetzingen, an academic teaching hospital affiliated with Heidelberg University, Germany.

During his long-term clinical practice in Germany, with access to state-of-the-art diagnostic and therapeutic technologies, Dr. Tsionis acquired extensive experience in both General Internal Medicine and the full spectrum of gastrointestinal diseases. He was successfully trained in all diagnostic and interventional endoscopic procedures of the upper and lower gastrointestinal tract. At the same time, he completed the required training in the Intensive Care Unit and, after many years of experience, obtained the specialization in Emergency Medicine (Notarzt), thereby making patient safety during medical procedures his/her primary priority. In recent years, as an instructor of the European Resuscitation Council (ERC), he has led an initiative to train the Greek gastrenterology community—through certified seminars—in the management of emergencies during endoscopic procedures.

During all these years, he completed the required training and was certified by the German Society for Ultrasound in Medicine (DEGUM) in performing ultrasound examinations, with specialization in abdominal organs, intestinal ultrasound, emergency ultrasonography, contrast-enhanced ultrasound (CEUS), as well as ultrasound-guided biopsies and other interventional procedures. Performing a high volume of ultrasound examinations over many years as head of the clinic’s ultrasound department contributed to the acquisition of extensive experience in complex cases encountered in daily clinical practice.

As a result of his long-standing involvement in the field of ultrasonography, his return to Greece was accompanied by regular lectures in this field at national conferences as an invited speaker. He also participated as an instructor in corresponding hands-on courses, actively contributing to continuing medical education in the field of gastrointestinal ultrasound. In addition, he served for two years as a scientific associate at the 2nd Propedeutic Medical Clinic of Hippokration Hospital of Thessaloniki, where, together with a team of specialized colleagues, they established the first organized Intestinal Ultrasound Unit in a public hospital in Northern Greece, dedicated to serving patients with Inflammatory Bowel Disease (IBD).

Since 2022, he has co-founded Gastroenterological Diagnosis of Serres together with his father and brother, establishing a model gastroenterology unit in Serres, thereby fulfilling a long-standing vision of providing modern, high-quality care in the field of Gastroenterology to the local community. Finally, in 2025 he was elected President of the Northern Greece Section of the Hellenic Society of Gastroenterology (HSG), with the promotion of ultrasound knowledge within the Greek gastroenterology community being one of the primary goals of his term of office.