 The homeless were targeted for these biopsies because they were painful and untested, and less vulnerable populations would not volunteer.Before securing a lead research position at Columbia University, Hudson received surgical training in the United States Navy and obtained a research position in urology at Johns Hopkins University under William Scott.Over time, Hudson's desire to learn more about prostate cancer led him to pursue a research position at Columbia University; where he led various research projects and was given ownership of various labs.