Medical Physics Seminar – Monday, March 28, 2011
Plastic Scintillation Detectors in Radiation Therapy: Old Concepts and New Applications
Luc Y. Beaulieu, Ph.D. (guest of Dr. Larry DeWerd)
Assistant Professor, Department of Physics & Physical Oceanography, Memorial University of Newfoundland & Labrador, CANADA
Scintillation is a process by which the deposited energy by ionizing radiation is converted to optical photons via series of vibrational and rotational transitions in the material. Plastic scintillators have been known in the nuclear physics community for a long time and the relationship between the light intensity and the deposited energy (or the stopping power) is known to be linear above a certain threshold. Plastic scintillators have numerous properties that make them ideal as radiation detectors for radiation therapy applications. A part from linearity to dose, the following were also demonstrated: water equivalence, temperature-pressure independence, dose rate independence and particles energy independence over a useful range. This presentation will review scintillation physics and plastic scintillator properties. We will revisit old concepts, such as the dosimeter proposed by Beddar, Mackie and Attix and look in the second generation of detectors that have been proposed recently. Extension to new detection apparatus concepts will also be presented.