EdU	5-ethynyl-2′-deoxyuridine
GI	gastrointestinal
H&E	haematoxylin and eosin
ISC	intestinal stem cell
IHC	immunohistochemistry
OLFM4	Olfactomedin 4
PBT	proton beam therapy
RBE	relative biological effectiveness
RT	radiation therapy
SOBP	spread-out-Bragg-peak
TUNEL	terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling