Imaging for early stage breast cancer

Intrafractional cavity motion

Direct monitoring the surgical cavity on cine MR during the irradiation (MRIdian, ViewRay Inc.)

- 30 patients - tracking of cavity motion - PTV = CTV

fractional time that the cavity occupies a given position during treatment delivery

- median reduction of PTV volume was 52% with no-PTV margin - mean cavity displacement in both AP and SI directions was 0.6 mm systematic - mean margin to account for intrafractional cavity motion was 0.7 mm

Acharya et al. IJROBP, doi: 016/j.ijrobp.2016.08.006