| Schedule | Constraint | Source |
|---|---|---|
| Conventional fractionation 70 Gy / 35 fx definitive · 60–66 Gy / 30–33 fx post-op | Mean ≤45 Gy | Emami 2013, Scoccianti 2015, QUANTEC hearing |
| V55 Gy <5% | RTOG 0615 |
Keep as low as possible to reduce hearing loss.
Quoted from eviQ 5049, checked 2026-09-24. Full table with references →
The spiral organ of hearing in the inner ear, embedded in the petrous part of the temporal bone.
The hearing organ of the inner ear. It turns sound vibrations into nerve signals that travel to the brain.
Dose to the cochlea can cause sensorineural hearing loss, and cisplatin adds to the risk — which is why it matters most in nasopharynx and oropharynx chemoradiation. QUANTEC reviews the dose–effect data. In brain treatment it matters for temporal lobe and posterior fossa targets, and for radiosurgery near the internal auditory canal.
Brouwer 2015 places it in the temporal bone, lateral to the internal auditory meatus, and recommends a CT bone window to find it. The EPTN 2018 atlas adds:
Because it is so small, Brouwer 2015 suggests expanding it by 5 mm when calculating DVH data, to make the numbers more consistent (while avoiding overlap with the PTV), and recommends a contrast CT with slices of 2 mm or less.
Consensus CT delineation guidelines for head and neck organs at risk from eight cooperative groups, with anatomical descriptions and example images. Citation checked against Crossref; content not yet reviewed by DoseLab.
The European Particle Therapy Network contouring atlas for brain organs at risk on CT and MRI, with anatomical descriptions and boundaries. Citation checked against Crossref.