How do you approach repeat SBRT in the abdomen, specifically when considering constraints for bowel and mesenteric vessels?  

Assume that a patient has had >1 year since previous SBRT treatment, and that they are not a surgical candidate. The previous dose was 30 Gy in 5 fractions for a metastatic colon cancer. Would you ever constrain the mesenteric vessels similarly to the great vessels in thoracic SBRT?