Invited Lecture 3.1

Abstract

Total Body Irradiation (TBI) was first reported in 1905. In the following years the best results were obtained for hematological malignancies. A variety of treatment approaches was developed. With the recent introduction of Tomotherapy and VMAT more advanced TBI and Total Marrow/Lymph Node Irradiation (TMLI) techniques have become available. Differences in techniques and dose-fractionation schemes have shown to complicate comparison of clinical results. Surveys held in the 1980s, and more recent surveys, have shown that TBI treatments, techniques, dose reporting and planning varied widely. State-of-the-art techniques, such as VMAT TBI/TMLI, are based on CT-planning with incorporation of auto-delineation and auto-planning to reduce treatment preparation time. They offer improved sparing of normal tissues, but the complexity of delivery has increased significantly.The large number of beams and isocentres, and patient rotation halfway through the treatment demands a prospective risk analysis prior to the introduction of such a technique. Automation of the process might be able to help both safety and performance.It would be helpful if VMAT TBI/TMLI converges to a more general technique including auto-delineation and auto-planning to shorten preparation times, an easy patient-rotation method to shorten treatment times, to improve patient setup and to prevent errors in performance. This also would make it easier for others to adopt these treatments.
Standardized reporting metrics should be developed to facilitate inter-institution comparisons. Older TBI techniques are inherently robust for patient movement due to the large fields used, but the use of multi-field junctions could lead to over/underdosage due to patient movement between beam delivery. In the planning process inherent robust techniques should be employed.In conclusion, VMAT TBI/TMLI techniques will become clinically feasible in a safe way only if treatment preparation is automated, if patient rotation can be performed efficiently and safely, and if software guides the delivery of multi-isocentric beams.