Optimization of CT Planning Imaging and Techniques to Reduce Radiation Dose Resulting from Daily
Imaging Guidance Procedures
IGRT has significantly improved the accuracy of radiation treatment by utilizing CT scans for contouring
target and organ during treatment planning and x-ray imaging devices integrated to treatment units for
patient positioning during radiation delivery. A significant progress has been made recently to improve CT
image quality in treatment planning and to reduce daily imaging guidance dose. This course is designed
to provide educational guidance on these two important imaging issues.
I) Optimization of CT Simulation Imaging. This part will provide guidance on optimizing CT image quality
in radiation therapy. There have been many publications on optimizing CT protocols for diagnostic imaging
purposes. However, the effort to optimize CT protocols for imaging applications in radiation therapy has
been limited. Although some lessons we learn from diagnostic CT imaging can be applied to CT imaging in
radiation therapy, there should be more emphasis on task-based image quality. In addition, there are
imaging features widely used in diagnostic CT imaging (e.g., metal artifact reduction) may not be well
known in radiation therapy community but can play critical roles for accurate radiation treatment
planning. This part of the session will feature a conversation between a radiation therapy physicist and a
diagnostic imaging physicist focusing on the needs specific to CT simulation imaging in radiation therapy
and the approaches to address these needs.
II) Techniques to reduce radiation dose resulting from daily imaging guidance procedures. This part will
provide an overview of radiation dose to patients resulting from different image devices used in imageguided procedures and provide guidance on the techniques available to reduce imaging dose resulting
from daily imaging guidance procedures. Depending on the image modality including MV and kV imaging
devices, a variety of techniques are available to significantly reduce daily imaging guidance dose to organs
at risk. Different methods of accounting for the imaging doses will be discussed.
Learning Objectives:
1) Understand CT image quality needs specific to imaging applications in radiation therapy
2) Learn the imaging acquisition and reconstruction optimization for CT imaging applications in
radiation therapy
3) Discuss appropriate approaches to optimize CT protocols in radiation therapy;
4) Briefly review the typical radiation dose to patients resulting from different image-guided
procedures MV and kV imaging modalities;
5) Learn the techniques available to reduce imaging dose
6) Discuss different methods of accounting for the imaging doses