On target 2: updated guidance for image-guided radiotherapy

This report was commissioned by the Radiotherapy Board to support the continued application of image-guided radiotherapy (IGRT) and to enable the future implementation of four-dimensional (4D) adaptive radiotherapy (ART) throughout the United Kingdom (UK). The 2008 report On Target: ensuring geometric accuracy in radiotherapy (published jointly by the Society and College of Radiographers (SCoR), the Institute of Physics and Engineering in Medicine (IPEM) and The Royal College of Radiologists (RCR)) recommended best, evidence-based practice for geometric treatment verification at a time
when kiloVoltage (kV) and three-dimensional (3D) volumetric imaging were emerging, hence the focus was primarily on megavoltage (MV) imaging.1 A later report, produced in 2012 by the National Radiotherapy Implementation Group and commissioned by the National Cancer Action Team, provided an update to On Target and included volumetric and fiducial marker imaging.2 Both documents were reviewed to provide the basis for this updated guidance, which
includes new and emerging technology and practice.