Presented by Daniel Bailey, PhD, DABR
Sarah Cannon, the Cancer Institute of HCA Healthcare

Circumstances often arise in radiation oncology in which different total doses and fractionations, whether delivered to targets or organs at risk, must be analyzed for comparability of biological effectiveness.  In these situations, Biologically Effective Dose (BED) and Equivalent Dose in 2 Gy/fx (EQD2), based on the linear quadratic model of cell survival, are the two most common analytical tools put to the task by dosimetrists, physicists, and physicians.   However, the accurate use of these radiobiological model parameters is nuanced by many potential variables, and ever-evolving with increasing published data.  Even though a number of free-source online and proprietary software tools are available to make rudimentary BED and EQD2 calculations easily accessible to clinical professionals, the appropriate use of these calculations is not always understood by all members of the radiotherapy team.  In this session, we will overview the background of BED and EQD2 calculations, including how their formulations have changed and improved over time.  In addition, we will examine the calculation framework for these radiobiological parameters, including looking at helpful resources to make calculations faster and more accurate during clinical routine. 

Finally, we will explore the practical use of these in realistic clinical situations to better understand the accurate and appropriate use of each parameter for:
1) different treatment scenarios and
2) different anatomical targets

Learner Outcomes:

1. Explain the background of BED and EQD2 calculation and use  
2. Calculate BED and/or EQD2 with appropriate consideration of alpha/beta ratios from current published literature  
3. Apply BED and EQD2 to real clinical scenarios in order to better understand the radiobiological effectiveness of different dose deliveries to targets and organs and risk

Presenter:
Daniel Bailey, PhD, DABR, completed his graduate degrees and clinical residency through the Physics department at the State University of New York at Buffalo in collaboration with the Medical Physics program at the Roswell Park Cancer Institute, also in Buffalo NY.  Dan is actively involved in the AAPM, AAMD, and ABR professional organizations, and is currently the Director of Physics and Dosimetry for Sarah Cannon, the Cancer Institute of HCA Healthcare.  His research and clinical-improvement activities include SRS, SBRT, SGRT, quality assurance and dosimetry techniques, total body irradiation, and improving the quality and safety of the modern radiotherapy workflow.

Educational Level: Advanced