A sensitive directional gamma-ray detector.

Directional scintillation detector probe. Cassen assembled the first automated scanning system, comprised of a motor driven scintillation detector coupled to a relay printer. The scanner was initially used to image thyroid glands after the administration of radioiodine.  Later, with the development of organ-specific radiopharmaceuticals, the scanner was widely used during the late 50s until the early 70s to image body organs. With L. Curtis and C. W. Reed.