Intensity modulated radiotherapy (IMRT) has improved the capability to apply geometrically individualised high radiotherapy doses to the prostate bed, prostate and seminal vesicles. A high risk of geometrical miss with conformal methods, however, has been documented for mobile targets such as the prostate. Modern, non-invasive localisation techniques are therefore mandatory to further optimise conformal radiotherapy for prostate cancer. This review summarises technological advances related to "image-guided radiotherapy" (IGRT) which will further improve target positioning in prostate cancer radiotherapy.