Table 2: Target and OAR definitions.

StructureDefinition

GTVGross tumor as visualized on MRI (T2) and physical exam
CTV Entire cervix for most patients, including extracervical disease if present on pre-SBRT MRI
PTVCTV plus expansion of 5 mm (using less of an expansion if adjacent to organs at risk)
RectumEntire rectum, superior limit will be rectosigmoid junction
BladderEntire bladder and contents
Small bowelBowel loops up to 2 cm above target