Index of content:
Volume 36, Issue 6, June 2009
- Therapy Symposium: Ballroom D
- Automated Segmentation for Radiotherapy Volume Definition
36(2009); http://dx.doi.org/10.1118/1.3182458View Description Hide Description
One of the more exciting advances in radiation therapy is the potential for customizing therapy for each patient through the model of adaptive radiation therapy(ART). This includes obtaining 3‐dimensional functional and anatomic images throughout the course of therapy using both in‐room and conventional imaging platforms. Image acquisition is only the first step in monitoring the quality and efficacy of treatments. The images need to be segmented to allow dosimetric evaluations and comparisons with earlier image datasets. The comparisons will be conducted both to evaluate dose distribution delivery and radiation response and may require acquisition and analysis of multiple image datasets throughout therapy. One of the greatest time consuming aspects of radiation therapy treatment planning is the process of segmenting tumors and normal organs. The expectation that the manpower bandwidth will be available to significantly increase this workload is not realistic, so automated and validated technologies will be necessary to enable wide‐spread implementation of ART. One of the greatest challenges for ART will be to develop efficient and effective methods for reviewing the automated segmentation output. The current paradigm of evaluating structure contours on a slice‐by‐slice basis is too time consuming and does not take advantage of the natural anatomic characteristics of the structures being reviewed. A more efficient method for segmentation review will be required. Automated techniques will also be necessary to map tissue deformation that occurs due to normal day‐to‐day setup and internal organ variations as well as radiation response and disease progression or regression. This symposium will present the state‐of‐the art in automated segmentation, deformable image registration, and segmentation review technologies, technologies that will be critical to the effective implementation of ART.
- Imaging and Treatment Planning for Adaptive Radiotherapy in the Head and Neck
36(2009); http://dx.doi.org/10.1118/1.3182514View Description Hide Description
The integration of in‐room volumetric imaging into the treatment delivery process has provided the ability to identify soft tissue changes in the head and neck over the course of radiotherapy. These changes include tumor response and changes in the position and volume of normal tissues. When these changes are substantial, registration of the daily online image to the planning image becomes challenging, if not impossible, and may result in a large change in the intended dose to the tumor and a violation of the dose constraints for the surrounding normal tissue. Research has begun to examine the implications associated with addressing these issues through adaptive radiotherapy, and commercial treatment planning systems are beginning to include the structure necessary for handling these changes. This symposium will describe techniques for performing adaptive radiotherapy including imaging for adaptive radiotherapy, deformable registration and dose accumulation, replanning and re‐optimization which includes the delivered dose, optimizing re‐planning timing, and clinical significance. To address these important issues surrounding imaging and treatment planning for adaptive radiotherapy in response to soft tissue changes, this symposium will be divided into the following four topics. Imaging and immobilization for adaptive radiotherapy in the head and neck will be examined, including identifying the need for replanning, the level of image quality necessary to accomplish this task, as well as immobilization and positioning strategies. Deformable registration and dose accumulation in the head and neck will be discussed, evaluating quality assurance, accuracy, and validation techniques and methods to handle volume reduction. Including the delivered dose, improving efficiency, and optimizing the number and timing of replanning events will be evaluated in the context of replanning and re‐optimization for head and neck. The clinical significance of performing adaptive replanning will be highlighted, including a presentation on the results of studies performed and a look to the future as to what studies should be performed.
1. Understand when re‐planning is necessary and the level of image quality required for re‐planning.
2. Understand the accuracy achievable and validation methods for deformable registration techniques used to relate in‐room volumetric imaging to the planning dataset.
3. Discuss dose accumulation, including methods for handling volume reduction and QA.
4. Review and evaluate current state‐of‐the‐art capabilities for re‐planning with regards to incorporating delivered dose, efficient workflow, as well as visualization and quantification of results.
5. Explore methods for optimizing the frequency and timing of re‐planning events.
6. Understand the clinical significance of adaptive planning with regards to reported results to date and potential future results
- Improving the Radiation Therapy Process Using Industrial Process Development Techniques
TU‐D‐BRD‐01: Improving the Radiation Therapy Process Using Industrial Process Development Techniques36(2009); http://dx.doi.org/10.1118/1.3182366View Description Hide Description
One of the emerging research and practical clinical topics is involvement of established modern industrial systems engineering methods to improve quality and safety of radiation oncology facilities. In systems engineering, mathematical modeling techniques are used to analyze the coordination, synchronization, and the integration of complex systems of personnel, information,materials, and resources. Since the 1940s, major industries have been developing processes to improve quality and safety of their operations and products. These efforts have matured over the years and through use of industrial and systems engineering methods many industries have significantly better safety and performance records than today's healthcare institutions, including radiation oncology. The opportunity to employ systems engineering principles to develop radiation oncology facilities into highly reliable organizations has been recently recognized in several high profile publications. This opportunity includes all areas of radiation therapy from patient interactions, through imaging, planning and delivery process, to standardization and benchmarking of our practices. The AAPM has also recognized that there is a need to develop quality assurance programs based on systems engineering principles and has established a TG100 which is developing recommendations for establishment of individual radiation oncology QA programs using industrial process development tools.
This session consists of four presentations which discuss the history of research on quality that led to the development of organization‐wide quality programs such as Six Sigma, including discussion of the current approach to quality in radiation oncology as well as where quality should be in the future. An analysis of opportunities for implementation of industrial engineering tools in radiation oncology for improvement of quality, safety, and efficiency is further provided. Two presentations discuss actual clinical processes which were developed using industrial engineering methods and their effects on the respective radiation oncology practices.
1. To describe history and development of industrial quality measures
2. To describe opportunities for employment of industrial engineering methods for improvement of radiation oncology practices
3. To describe development of actual clinical process based on industrial engineering principles and their effects on clinical operations