The ESOI workshop is an interactive hands-on course aimed at practising radiologists and radiology residents, focusing on the criteria-based assessment of tumour response to treatment. The course consists of a number of lectures explaining the principles of imaging-based tumour response assessment and several hands-on interactive training workshops using specialised software with common and rare cancer cases encountered in the clinical routine or within clinical trials. A Certificate of Attendance will be issued by the European Society of Oncologic Imaging (ESOI) to participants who attend the workshop and meet the minimum requirements for attendance.