Positron Emission tomography Response Criteria In Solid Tumors (PERCIST) version 1.0 was introduced in 2009 for objective assessment of tumor metabolic response using 18F-FDG PET/CT. Practical PERCIST: A Simplified Guide to PET Response Criteria in Solid Tumors 1.0 was published in 2016 to review and clarify some of the issues with the PERCIST. In this article, we reflect on the benefits and challenges of implementing PERCIST, and speculate on topics that could be discussed in PERCIST 1.1 in the future.