Palliative whole-brain radiotherapy: usually two opposed lateral fields shaped to the base of the skull, delivered in 5 or 10 fractions. The planning work is in covering the whole brain down to the skull base while keeping the beams off the lenses.
Palliative whole-brain radiotherapy (WBRT) is usually 30 Gy in 10 fractions or 20 Gy in 5 fractions. One current protocol notes that 30 Gy in 10 was the standard in many trials, but that there is no evidence it is better than 20 Gy in 5.
It is used when there are too many metastases, or they are too widespread, for radiosurgery, and for patients who aren't candidates for hippocampal avoidance. For patients with a poor prognosis, the QUARTZ trial found that adding WBRT to steroids and supportive care gave little benefit. Patients with a better prognosis may instead be offered hippocampal-avoidance whole brain — a different, IMRT-based technique with its own page.
A simple setup, but reproducibility still matters for the lenses and the skull base.
Supine with the head neutral in a thermoplastic mask and a neck support, arms by the sides.
A straight head keeps the two lateral fields symmetric and the skull base in a predictable line on the images, which makes shaping the field edge and sparing the lenses straightforward.
A CT covering the whole head and upper neck, used to shape the fields on a digitally reconstructed radiograph (DRR).
Some departments still use clinical mark-up or simulation on the treatment couch for urgent palliative cases; a CT allows the dose to be checked and the lenses and field edge to be seen in 3D.
How a conventional whole-brain plan is built. Field edges and margins come from your protocol.
Two parallel-opposed lateral beams covering the whole cranial contents, with the field open beyond the skin at the top and back of the head (flash).
Flash makes sure the whole brain is covered despite small setup changes and the dose build-up near the skin. Dose is often specified at the midplane of the two beams; field-in-field segments can even out hot spots where the head is narrower.
The lower edge of the field is shaped with the multileaf collimator to follow the base of the skull — the cribriform plate, the middle cranial fossa and the foramen magnum — while blocking the face, eyes and neck.
The brain dips lowest at the temporal lobes and around the foramen magnum, so a straight field edge would either miss brain or treat much more face and neck than needed. Recurrences at the skull base are a known risk of blocking too tightly.
Keeping the anterior field edge behind the lenses, and angling the beams slightly or placing the isocenter at the level of the lateral canthus so the divergent edge doesn't clip the opposite lens.
Because the beams diverge, a field edge that sits behind one lens can pass through the other. The lens is highly sensitive to radiation, so this is a routine check on the DRR.
Click an organ for its anatomy, why it matters and contouring resources.
| Organ | 30 Gy / 10 fxor 20 Gy / 5 fx |
|---|---|
| LensTarget coverage should not be compromised to meet this. |
|
| Parotid Glands |
|
Values quoted from eviQ 1251 (last reviewed 21 August 2025; review due 31 December 2029), checked by DoseLab on 2026-09-25. Verify against your protocol, institutional policy and physician directive before clinical use.
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ASTRO clinical practice guideline on radiotherapy for intact and resected brain metastases: when to use SRS, when to consider surgery, and hippocampal avoidance with memantine for patients with a good prognosis who receive whole-brain treatment. Citation checked against Crossref.
Phase 3 non-inferiority trial (QUARTZ) in non-small cell lung cancer with brain metastases unsuitable for surgery or SRS: adding whole-brain radiotherapy, 20 Gy in 5 fractions, to supportive care gave little additional benefit. Citation checked against Crossref.
Phase 3 trial (NCCTG N0574) in patients with 1–3 brain metastases: adding whole-brain radiotherapy to radiosurgery caused more cognitive decline at 3 months without improving survival. Citation checked against Crossref.
The NRG CC001 trial protocol (version date 26 September 2017, copy posted on ClinicalTrials.gov for NCT02360215). Arm 1 was standard whole-brain radiotherapy with 3D conformal fields; arm 2 was IMRT-based hippocampal avoidance, both 30 Gy in 10 fractions with memantine. Sections 5.2.4–5.2.8 define the CTV and PTV, the required structures (hippocampi, the hippocampal avoidance region, lenses, optic nerves and chiasm), the normalization, the per-protocol and variation-acceptable limits for the PTV, hippocampi and optic structures, and the planning priority order. DoseLab's hippocampal avoidance table quotes section 5.2.7 directly.
Endorsed eviQ protocol for palliative whole-brain radiotherapy, 30 Gy in 10 fractions or 20 Gy in 5 fractions with 2D or 3D conformal fields. Its organ table lists the lens and parotids. DoseLab's whole brain table reproduces those two rows.