TH‐B‐AUD A‐01: Accurate Clinical Measurements

Image‐guided radiation therapy deliveries are becoming increasingly complex and their verification involves clinical measurements in situations that are no longer covered by reference dosimetry protocols or relative dosimetry procedures with simple corrections. In this era of joint imaging‐therapy developments, accurate dosimetry techniques are sometimes trivialized and important effects not understood or ignored. However, clinical measurements increasingly involve reference and relative dosimetry of complex charged particle disequilibrium configurations and their interpretation. This presentation consists of two parts: the first part revisits principles of measurement dosimetry, definitions of detectors and phantoms, reference dosimetry for conventional beams and also discusses some new developments in reference dosimetry of non‐conventional beams. The second part of the presentation concentrates on relative dose measurements with the goal to generate 3D distributions as well as integrated measurements and derived quantities. We conclude with a discussion of relative dosimetry in special cases including the photon build‐up region as well as narrow 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 standard clinical reference dosimetry techniques and be exposed to some of the new developments in reference dosimetry in non‐standard beam configurations. 4. To get an overview of relative dosimetry techniques for the purpose of 3D dose distributions 5. To be aware of the complications of measurements in electronic disequilibrium such as in the photon build‐up and for small photon fields.