The German researchers from Dresden, Essen and Heidelberg together developed a NTCP model for acute side-effects including alopecia, scalp erythema, headache, fatigue and nausea, after proton therapy. The study reported that V35Gy (absolute volume receiving 35 Gy) for erythema grade ≥1, D2% (dose to 2% of the volume) for alopecia grade ≥1 and D5% for alopecia grade ≥2.

The study concluded that the NTCP model was developed and successfully validated for scalp erythema and alopecia in primary brain tumour patients treated with PBT.