TH-A-M100A-01: Accurate Clinical Measurements

Abstract

Radiation therapy is rapidly moving into the direction of image guidance, functional target volumes, hypofractionation, dose escalation and 4D deliveries. In this era of joint imaging-therapy developments, accurate dosimetry techniques are often considered an issue of the past. However, clinical reality increasingly requires dealings with non-protocol compliant reference dosimetry as well as complex charged particle disequilibrium measurements and their interpretation. This presentation consists of two parts: the first part will review principles of measurement dosimetry, definitions of detectors and phantoms, reference dosimetry for conventional as well as non-protocol compliant technologies. The second part will review principles of relative dosimetry measurements, focusing on scanning and integrated measurements usually performed at time of beam commissioning. We will conclude with a discussion of dosimetry in special cases including the photon build-up region as well as narrow and dynamic fields. Educational Objectives 1. To understand the principles of clinical measurement dosimetry. 2. To get an overview of detectors and phantoms for reference and relative dosimetry. 3. To understand reference dosimetry techniques in protocol compliant and non-compliant beam arrangements. 4. To understand relative dosimetry techniques for the purpose of 3D dose distributions and to grasp areas of complication. 5. To understand integrated relative dosimetry measurements in photon and electron beams. 6. To be aware of non electronic equilibrium types of measurements in the photon build-up and for small photon fields.