Case F: Workflow Improvement of Image-guided Radiotherapy

Work Packages: WP3

Background: High risk prostate cancer patients are treated in 20 fractions of 3.1 Gy, with a focal GTV boost up to 3.7 Gy, on the MR-linac. Because of efficiency reasons this is done in an Adaptto-Position (ATP) procedure, which takes about 20 minutes of total treatment time per fraction. About half of this time is image acquisition, registration and ATP plan calculation. However, because the ATP only corrects for translations, not rotations or deformations, quite large PTV margins of 5 mm are required. Furthermore, seminal vesicles can show large relative motions with respect to the prostate, which are also not corrected for.

Objective: To develop a method to allow for correction of prostate rotations and deformations (seminal vesicles) while not increasing timeslots with respect to the current ATP procedure. To investigate if PTV margins can be decreased to 3 mm.