ESTRO course on Image Guided Radiotherapy in Clinical Practice 2018

Future: MRI informed real-time planning

• 3D gradient echo T1-weighted mDixon sequence scan time: 40 s; (Philips Ingenia 1.5T) • MRI at t = 0, 2, 4, 6, 8, and 10 minutes • Bladder CTV, bowel loops and rectum were delineated on MRI_0 and MRI_10 • Dose plans calculated on MRI_0 • Target coverage assessed on MRI_10

• Reduction in PTV course average (median 304 cc compared to plan selection) • Improved bowel loop sparing (V25) • V95 <98% in 2 patients (intra-fraction shifts)

Vestergaard A, Hafeez S, Muren LP, Nill S, Hoyer M, Hansen VN, Gronborg C, Pedersen EM, Petersen JB, Huddart R et al: The potential of MRI-guided online adaptive re-optimisation in radiotherapy of urinary bladder cancer. Radiother Oncol 2016, 118(1):154-159.