Imaging Endpoints has maintained a leadership role in PET imaging services and analysis for the clinical trial industry for many years. There has been tremendous growth and innovation in recent years with PET being routinely used in clinical diagnosis and staging as well as monitoring of cancer treatment. Additionally, PET has become a very robust tool in clinical trials, where the use of PET follows two distinct approaches - qualitative assessment and quantitative assessment. A typical qualitative assessment may focus on the overall visual assessments of activity on whole body scans while quantitative assessment requires a high degree of analysis and dedication on the part of the clinical site performing PET scans and upon the reader evaluating those images in the context of the extent of disease and response following therapy. Here we discuss when to consider implementing PET imaging in a clinical trial as well as other PET agents that may be considered.