• Chairs : Jan Unkelbach & Ben Heijman


Among the three radiotherapy target volume concepts - GTV, CTV, PTV - the definition of the CTV has arguably made the least progress. While GTV definition steadily improves through novel biomedical imaging techniques and the PTV shrinks through image guidance, CTV definition is often considered the weakest element in modern precision radiotherapy. By definition, the CTV is not visible as a macroscopic tumor mass on imaging. Instead, CTV delineation is based on the anatomically defined patterns of tumor progression. Within the medical physics community, the CTV is mostly considered the domain of radiation oncologists and has attracted relatively little research attention. However, medical physics can make substantial contributions by developing computational methods to support CTV definition and the use of the CTV in planning. Examples are

  • Medical image computing algorithms to automate CTV delineation and consistently account for anatomical routes and barriers for tumor progression.
  • Mathematical and statistical models of tumor progression that predict the extent of microscopic disease more accurately based on quantitative analysis of imaging, histopathology, and patterns of failure.
  • Development of probabilistic optimization approaches that explicitly account for gradual microscopic infiltration and uncertainties in the extent of disease. 

This being a workshop we want to encourage an active participation and interaction between the participants to foster collaboration and networking. For that reason, participants will be requested to prepare a short presentation (a pitch) to present their research in the field allowing identification of common points of interests and share experiences.


The goal of the workshop is to exchange work on computational methods to support CTV delineation and use of the CTV in planning and bring together medical physicists, radiation oncologists, and computer scientists working in this field.

  1.  Summarize current work and formation of an international network of research groups.
  2. Promote and strengthen computational research on the CTV within the medical physics community. 
  3. Write a joint paper on the current state of computational methods for handling microscopic disease and define future research direction