Stereotactic Body Radiotherapy as an Alternative to Brachytherapy in Gynecologic Cancer

Table 2

Target and OAR definitions.

Structure	Definition
GTV	Gross tumor as visualized on MRI (T2) and physical exam
CTV	Entire cervix for most patients, including extracervical disease if present on pre-SBRT MRI
PTV	CTV plus expansion of 5 mm (using less of an expansion if adjacent to organs at risk)
Rectum	Entire rectum, superior limit will be rectosigmoid junction
Bladder	Entire bladder and contents
Small bowel	Bowel loops up to 2 cm above target