Radiation therapy has advanced dramatically in the last two decades. With advanced technology, higher doses of radiation are being given with much greater precision. A roadblock for improving quality of radiation therapy has been managing variations in patient setup compared to planning images. Better on-treatment imaging as well as automation utilizing artificial intelligence has enabled the adaptation of patient plans with the patient on the machine. This talk will present how radiation therapy has changed over time. In particular two different adaptive radiotherapy systems will be discussed as well as the important role the physicist plays in ushering in new technologies into the clinic.