| Schedule | Constraint | Source |
|---|---|---|
| 70 Gy / 28 fx Moderate hypofractionation | Mean dose <50 Gy | ASTRO DVH Compendium 2026 |
| 78–80 Gy / 39–40 fx Conventional | Mean dose <52.5 Gy | QUANTEC, RTOG 0126 |
Never at the expense of PTV coverage.
Quoted from ASTRO DVH Compendium 2026 and eviQ 234, checked 2026-10-14. Full table with references →
Never at the expense of PTV coverage.
Quoted from eviQ 3657, checked 2026-09-23. Full table with references →
| Schedule | Constraint | Source |
|---|---|---|
| 36.25 Gy / 5 fx To PTV (40 Gy to CTV) | V29.5 Gy <50% | PACE-B |
| V36 Gy ≤0.1 cc | TROG NINJA |
Quoted from eviQ 4140, checked 2026-09-22. Full table with references →
The expanded proximal part of the corpus spongiosum, lying just below the urogenital diaphragm and below the prostatic apex. It is easiest to see on MRI; on CT it can be hard to separate from surrounding tissue.
The penile bulb is the base of the corpus spongiosum, the erectile tissue around the urethra at the root of the penis.
Penile bulb dose has been studied as a surrogate for erectile dysfunction after prostate radiotherapy. The link is not firmly established, and sources consistently note that sparing the bulb should not compromise coverage of the prostate apex — the risk of under-dosing the target outweighs the uncertain benefit.
Gay 2012: the part of the bulbous spongiosum immediately below the urogenital diaphragm; do not extend it forward into the shaft. It is best seen on MRI (bright on T2) or on CT with contrast in the urethra; on CT it sits behind the urethra and is round.
Timmerman 2022 (Tables 8–11, written for its SBRT dose tables): start at the bottom of the pelvic diaphragm (urethral sphincter) and extend down and forward up to 3 cm.
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.