SPIE, along with the support of the American Association of Physicists in Medicine (AAPM) and the National Cancer Institute (NCI), will conduct a “Grand Challenge” on quantitative image analysis methods for the diagnostic classification of clinically significant prostate lesions. As part of the 2017 SPIE Medical Imaging Symposium, the PROSTATEx Challenge will provide a unique opportunity for participants to compare their algorithms with those of others from academia, industry, and government in a structured, direct way using the same data sets. To learn more about the challenge please visit http://spie.org/x115569.xml?wt.mc_id=rmi17gb. Researchers interested to participate in ongoing performance evaluation can also visit https://prostatex.grand-challenge.org/challenge_description/.