ABSTRACT
Figure 11.1 shows the overall ²owchart for plan adaptation. Ÿis concept is not new, having been discussed by several investigators (Yan et al. 1998; de Boer and Heijmen 2001). In its basic form, the concept is simple. An initial treatment plan is developed for treating the patient. Ÿis plan is based on historical knowledge of previous patients with similar anatomy, positioning, immobilization, and disease. As such, assumptions are made, particularly with respect to the geometric variations that the patient is expected to undergo as treatment progresses. Ÿe potential exists, however, to “learn” about speci£c patient issues, including, but not limited to, geometric variations, and to apply this knowledge to modify the treatment plan (as well as strategies such as the frequency and tolerance of setup veri£cation) to the bene£t of the individual patient. Ÿe trick to doing so is to gain and act on this knowledge in a su›ciently timely
fashion, so that the patient can bene£t from the modi£cation of the remaining treatment fractions.
