1. VisionRT, London, UK. Available from: www.visionrt.com/.
2. Catalyst, C-RAD, Uppsala, Sweden. Available from: www.c-rad.se/catalyst-plus.
3. Varian Identify, Palo Alto, California, USA. Available from: www.varian.com/products/radiotherapy/real-time-tracking-motion-management/identify.
4. Brain Lab, Exactrac Dynamic, Munich, Germany. Available from: www.brainlab.com/radiosurgery-products/exactrac/.
5. Use of surface‐guided radiation therapy in combination with IGRT for setup and intrafraction motion monitoring during stereotactic body radiation therapy treatments of the lung and abdomen;Heinzerling;J Appl Clin Med Phys,2020