What is the best way to monitor a brain tumor? This question is at the heart of a new Position Statement published in open-access journal Frontiers in Oncology. The article is the work of a large collaboration of UK experts and stakeholders who met to discuss the value of routinely imaging brain tumor patients to assess their tumor treatment response, which is known as “interval imaging”. Their verdict: there is very limited evidence to support the practice at present. However, the article also discusses how future research could determine and maximize the value of interval imaging by assessing its cost effectiveness and how it affects patient quality of life, treatment and survival.