A New Quality Control System for Detecting Defects in Proton Range Modifiers for Proton Therapy

A NEW QUALITY CONTROL SYSTEM FOR DETECTING DEFECTS IN PROTON RANGE MODIFIERS FOR PROTON THERAPY Brad Kreydick, B.S. Department of Physics Northern Illinois University, 2013 George Coutrakon, Ph.D., Director Proton beam radiotherapy is an increasingly common and accepted form of cancer treatment, which utilizes the novel energy-deposition characteristics of heavy, charged particles to destroy tumor cells. At the CDH Proton Therapy Center in Warrenville, IL, the main beamdelivery technique employs patient-specific beam modifiers to conform the beam to the target area, both perpendicular to the direction of beam travel and along the beam’s axis. These devices are manufactured on-site using specifications generated by treatment planning software, and are subjected to several measurement and identification procedures to verify their integrity before use. A periodic manufacturing defect, not detected by this quality assurance procedure, was discovered by the author, and during the investigation to determine the root cause of the issue and whether the radiologic properties of the defects were relevant in clinical practice, a new quality assurance program was developed. NORTHERN ILLINOIS UNIVERSITY DE KALB, ILLINOIS