Dosimetry Measurements for Beam Commissioning

C-M Charlie Ma, Ph.D.

Professor and Director, Radiation Physics

Department of Radiation Oncology

For Chase Cancer Center

Philadelphia, PA 19111, USA

This refresher course is aimed at reviewing the practical aspects of dosimetry measurements for radiotherapy beam commissioning and clinical dose determination. The dosimetry chain, the detectors, and the formalisms used for the determination of absorbed dose for radiation therapy will be reviewed. The practical aspects of beam commissioning and quality assurance (QA) will be discussed. Important issues regarding dose measurements for treatment planning QA and beam delivery verification in intensity-modulated radiation therapy (IMRT) will be presented. The educational objectives are: (1) to understand the principles and operations of radiation detectors and dosimetry protocols and (2) to review the issues related to dose measurements for modern radiation therapy techniques with a focus on dose determination under charged particle disequilibrium conditions and the uncertainties in clinical dosimetry.