MR-guided Prostate Stereotactic Body Radiotherapy in Seven Days

The dose to the planning target volume (PTV) is 36 Gy (5 x 7.2 Gy) prescribed on the 90% isodose line. The clinical target volume (CTV) is receiving 40 Gy (5 x 8 Gy = 100%). A simultaneous integrated boost (SIB) up to a total dose of 42 Gy (5 x 8.4 Gy = 105%) is delivered to the gross tumor volume (GTV), if present. In addition, relative sparing of the urethra will be applied by avoiding hotspots (V40 Gy \< 1cc) in the urethra. Baseline and adapted treatment plans are generated using intensity-modulated RT