1. Dmitri Popov. PhD, Radiobiology. MD (Russia) Advanced Medical Technology and Systems Inc. Canada. Acute Radiation Gastro-Intestinal Syndrome.

2. Acute Gastro-Intestinal Radiation Syndrome.

8. Grading System for Acute Gastro - Intestinal Radiation Syndrome based on general clinical signs. Degree 1 – Mild GI ARS. Radiation GI Neurotoxins - SRD – 3.1. – Group. Nausea, Vomiting - Occasional (once per day). Anorexia - Able to eat, appetite decreased. Fatigue syndrome - Able to work. Hypotension - Blood pressure>100/70 mm Hg.

9. Acute Gastro-Intestinal Radiation Syndrome. Colon Epithelium deficit – increased apoptosis, focal necroptosis. Inflammation detectable, but not significant. Blood loss - Detectable, minor. Degree 2 of GI ARS - Moderate degree. Group of Radiation Neurotoxins SRD – 3.2. Nausea, Vomiting – Intermitted (2-5 times per day). Anorexia. Intake decreased.

10. Acute Gastro-Intestinal Radiation Syndrome. Fatigue syndrome: Impaired work ability. Hypotension: Blood pressure <100/70 mmHg. Colon Epithelium deficit: Easy detectable. Increased apoptosis, significant necroptosis. Blood loss - Moderate loss. Degree 3 – Severe degree of GI ARS. Radiation GI Neurotoxins: SRD – 3.3 Group. Nausea, Vomiting - Persistent (6-10 times per day). Bloody diarrhea. Need assistance in activity of daily living.

11. Acute Gastro-Intestinal Radiation Syndrome. Anorexia: Intake minimal, Parenteral nutrition. Hypotension - Blood pressure <90/60 mm Hg. Need blood components transfusion. Major blood loss. Life treating. Colon Epithelium deficit – significant damage, inflammation, necroptosis, some or significant ulceration with colon wall damage.

12. Acute Gastro-Intestinal Radiation Syndrome. Degree 4 – Extremely severe Grade of GI ARS. Radiation GI Neurotoxins: SRD – 3.1. Nausea, Vomiting: Extremely severe Refractory (>10 times per day) Anorexia: Parenteral nutrition. Fatigue syndrome: Severe fatique.

13. Acute Gastro-Intestinal Radiation Syndrome. Hypotension: Blood pressure <80/? Mm Hg; Heart beat cessation. Life threatening, Colon Epithelium deficit: Prominent loss of colon function with deep colon wall damage, epithelium necroptosis, necrosis, severe form of ulceration. Possible perforation, function cessation. Major bleeding from GI tract.

14. Acute Gastro-Intestinal Radiation Syndrome.

21. Gastrointestinal (GI) syndrome: the Acute Gastrointestinal syndrome occur with a dose greater than approximately 10 Gy (1000 rads) although some symptoms may occur as low as 6 Gy or 600 rads. Survival rate depend on severity of GI - ARS. Destructive and irreparable changes in the GI tract usually cause infection, dehydration, and electrolyte imbalance. Death usually occurs within 2 weeks.

22. Acute Gastro-Intestinal Radiation Syndrome. Gastrointestinal (GI) ARS usually develop together with Hematopoietic ARS. Gastrointestinal (GI) - Symptoms are anorexia, severe nausea, vomiting, cramps, and diarrhea. Onset occurs within a few hours after exposure. Stage lasts about 2 days. Hematopoietic ARS - Symptoms are anorexia, nausea and vomiting. Onset occurs 1 hour to 2 days after exposure. Stage lasts for minutes to days.

23. Acute Gastro-Intestinal Radiation Syndrome. Hematopoetic ARS (developing together with GI ARS) Stem cells in bone marrow are dying, although patient may appear and feel well. Stage lasts 1 to 6 weeks. GI ARS - Stem cells in bone marrow and cells lining GI tract are dying, although patient may appear and feel well. Stage lasts less than 1 week.

24. Acute Gastro-Intestinal Radiation Syndrome. Hematopoietic ARS - Symptoms are anorexia, fever, and malaise. Drop in all blood cell counts occurs for several weeks. Primary cause of death is infection and hemorrhage. Developing in together with GI – ARS.

25. Acute Gastro-Intestinal Radiation Syndrome. GI - ARS Symptoms are malaise, anorexia, severe diarrhea, fever, dehydration, and electrolyte imbalance + symptoms of Hematopoietic ARS. Death is due to infection, dehydration, and electrolyte imbalance. Death occurs within 2 weeks of exposure. The extent of colonic mucosal involvement and severity of disease correlate with the clinical manifestations of ulcerative radiation colitis.

26. Acute Gastro-Intestinal Radiation Syndrome. Mild Grade of Gastro- Intestinal ARS. Death in 10 - 15 days

27. Acute Gastro-Intestinal Radiation Syndrome. Moderate Grade of Gastro- Intestinal ARS. Death in 5-7 days

28. Acute Gastro-Intestinal Radiation Syndrome. Severe Grade of Gastro- Intestinal ARS. Death in 2 - 3 days.

29. Acute Gastro-Intestinal Radiation Syndrome. Extremely Severe Grade of Gastro-Intestinal ARS. Death in 24 hours.