Dr. Volakis is a Radiologist. Nicknamed "Cutthroat Bitch" by House, she was in the running to join Dr. House's diagnostic team but was eliminated from the competition for not being able to take criticism. She appeared in season 4 of House, MD.
She first appeared in the episode in which House seeks a new team member to replace Dr. Cameron. Every potential intern was given a nickname. Dr. Volakis was known as cut-throat bitch. A character trait of Amber was her willingness to do anything to succeed. As appealing as this was to House, Dr. House could not hire her because of that attitude. One had to be able to accept failure to be one of his doctors.
Following her elimination from the rounds to join House's medical team, Amber began dating Dr. Wilson. She became a reoccurring character, who often said the magic phrase that made the puzzle in House's head click into place, causing the camera to zoom in on Dr. House's forehead. Amber's love of James (Wilson) created an antagonistic relationship with Dr. House, eventually settling in the two deciding to create "shared custody of Wilson".
Dr. Volakis and Wilson began getting rather serious in their relationship, so much to the point that she was often given House-sitting duties. Until one fateful night. House had been drinking. He called Dr. Wilson to get a ride. Unbeknownst to House, it was actually Amber who picked up the phone. While on the way to bring House home, Amber dies as the result of a bus accident - her kidneys ruptured, and House was unable to cure her because the medication he prescribed her conflicted with the flu medication she was taking while on her designated driver duties.
Amber's death, naturally, causes a rift in the House-Wilson relationship - a major plot point in season 5. She appears in a few season 5 episodes as a ghost, haunting House, whose confidence was shaken by his inability to save Amber and his fear of facing Wilson, knowing that Amber's death was a direct result of his own actions.