| Schedule | Constraint | Source |
|---|---|---|
| 42–54 Gy / 3 fx Liver metastases | D0.1 cc ≤28.2 Gy | UK SABR consensus 2022 |
| 27.5–60 Gy / 5 fx HCC or metastases | D0.1 cc ≤38 Gy | UK SABR consensus 2022 |
Quoted from eviQ 4026, checked 2026-09-29. Full table with references →
| Schedule | Constraint | Source |
|---|---|---|
| 50.4–54 Gy / 28–30 fx Dose-painted IMRT | Loops V30 Gy <200 cc, V35 Gy <150 cc, V45 Gy <20 cc | RTOG 0529 |
Quoted from eviQ 1860, checked 2026-09-29. Full table with references →
The colon from the caecum to the rectosigmoid junction. In the pelvis the part that matters most is the sigmoid colon, which loops down from the left side of the pelvis and joins the rectum at the rectosigmoid junction — often lying just above the bladder and seminal vesicles.
The large intestine absorbs water and salts and stores stool.
For prostate treatment the sigmoid is usually a small but real concern: a loop that drops down toward the seminal vesicles or prostate bed can pick up high dose, especially when the bladder is less full than at simulation. The main concerns are colitis and, rarely, serious late injury. Few prostate-specific limits exist for the large bowel; many departments apply their rectal or small bowel limits to it, and published guidance advises avoiding hotspots in it and taking extra care with diverticular disease.
In GI treatment, large bowel limits appear mainly in liver SBRT (the hepatic flexure lies under the liver) and in anal cancer, where one protocol gives the same volume limits for large and small bowel loops. In rectal treatment the sigmoid and rectum next to the tumor are usually part of the target.
In cervix brachytherapy the sigmoid often lies on top of the uterus near the tandem, so it has its own D2cc limit in EQD2. EMBRACE II notes that sigmoid and bowel D2cc are reliable only when the loops don't move between fractions.
Timmerman 2022 (Tables 8–11, written for its SBRT dose tables): one structure, wall and contents, from 10 cm above to 10 cm below the PTV. Jabbour 2014 recommends tracking large bowel slice by slice in the upper abdomen.
CORSAIR's contouring table defines both a sigmoid and a large bowel structure, with the large bowel ending at the bottom at the rectosigmoid junction. Make the sigmoid–rectum boundary match how the rectum was contoured, so no segment is counted twice or missed.
RTOG consensus panel atlas of male and female pelvic normal tissues. Citation as given in the eviQ reference list; not yet checked against the journal.
An editorial history of the UT Southwestern SABR constraint tables — often called the “Timmerman tables” — covering how they were developed and revised, and their relationship to AAPM TG-101 and NRG/RTOG protocols. Tables 2–11 separate serial tissues (listed with a volume, a volume max and a max point dose) from parallel tissues (listed with a critical volume and a critical-volume dose max). In Tables 2–7 a footnote defines “point” as ≤0.035 cm³; Tables 8–11 add a contouring-instructions column for each structure.
RTOG consensus guidelines and atlas for delineating upper abdominal normal organs. Citation checked against Europe PMC.
An open-access multicenter summary of organ-at-risk dose–volume constraints for adults (Table 1) and contouring definitions based on the Global Harmonization Group nomenclature (Table 2). DoseLab uses its large bowel row where eviQ gives no number.