| Schedule | Constraint | Source |
|---|---|---|
| 45–50.4 Gy / 25–28 fx Long course | V40 Gy <40%, V45 Gy <25% | RTOG 0822 |
| Max <50 Gy | RTOG 0822 |
Quoted from eviQ 1863, checked 2026-09-29. Full table with references →
| Schedule | Constraint | Source |
|---|---|---|
| 50.4–54 Gy / 28–30 fx Dose-painted IMRT | V30 Gy <50%, V40 Gy <35%, V44 Gy <5% | RTOG 0529, NRG anal RT template |
Quoted from eviQ 1860, checked 2026-09-29. Full table with references →
The rounded upper ends of the femurs that sit in the acetabulum of the pelvis. Planning structures often include the femoral neck as well, down to about the level of the lesser trochanter.
The femoral head is the ball of the hip joint, carrying the body's weight from the pelvis to the leg.
The concern is femoral head necrosis or femoral neck fracture — rare with modern planning but serious. Lateral beams in older 3D techniques could deliver meaningful dose here; with IMRT and VMAT the limits are usually met easily, but they still need checking, especially when lateral arcs or beam angles concentrate dose through the hips.
In rectal and anal cancer the elective nodal volumes (internal and external iliac, and inguinal in anal cancer) sit close to the femoral heads and necks, so their limits are checked in every pelvic GI plan.
In gynecologic treatment the external iliac and (for vulvar cancer) inguinofemoral nodal volumes pass close to the femoral heads and necks. NRG's GYN templates write their limits as D15% plus a near-maximum (D0.03 cc).
Sources draw quite different structures:
Because the volumes differ, a limit only makes sense on the structure it was written for.
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.
The template NRG Oncology gives investigators for writing the radiation therapy section of an anal cancer trial. Its example text and values are based on RTOG 0529 and the ECOG-ACRIN DECREASE trial (EA2182), and are meant to be edited for each protocol. It covers immobilization (a supine "frog-leg" position is recommended), CT or PET/CT simulation, rigid registration of MRI and PET to the planning CT, standard structure names, dose compliance tables and planning priorities.
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.