Dr. Leo Fields 3 episodes, 2016-2017
Phil Quinlan 12 episodes, 2014
Ted Crisp / ... (26 episodes, 2009-2010)
Erik Luna (1 episode, 2009)
Dr. Wyatt Lockhart (5 episodes, 2008-2009)
Dr. Dan (1 episode, 2008)
Special Agent Paul Ryan (13 episodes, 2005)
Mark Powell (1 episode, 2005)
Dr. Simon O'Keefe (10 episodes, 2004-2005)
Dr. Ron McCready (7 episodes, 2006)
Steve Taylor (10 episodes, 2003)
Theodore Blumenthal (10 episodes, 2001-2002)
Dr. Ravoc (1 episode, 2001)