ESTRO 2022 - Abstract Book

S708

Abstract book

ESTRO 2022

Results 9 out of 69 patients were excluded from the model, considered to be dosimetric outliers for at least one structure. In the internal validation PTV, coverage (V95%) was improved (1% p<0.05) alongside D1% (0.4Gy p<0.05) and homogeneity (dose SD) (0.09Gy p<0.05). OAR mean dose was improved (p<0.05) with the automatic approach by 0.1/0.2/0.1/0.06 Gy for ipsil. lung/heart/contral. breast/ contral. lung respectively. 4 plans out of 30 resulted to be unacceptable in terms of PTV coverage: manually inserting one/two beams (up to a maximum of four) was sufficient to make the plans acceptable. Concerning the external validation, the general trend was replicated even though some differences were found to be not significant (p>0.05), due to the small available sample (Tab.1-Fig.1). All 10 plans were considered acceptable. A field width of 2.5cm was used for all KB-TD plans, resulting in a delivery time of 8±1min, comparing well with our clinical experience.

Conclusion We proposed an approach for large-scale automatic planning using the commercially available RP tool from Varian in a different environment. The KB-TD approach was able to generate automatic plans comparable to the clinical ones or slightly better in terms of PTV coverage, PTV dose homogeneity and Dm to body and OARs. Using four beams, no manual adjustment