(Sunday, 7/29/2018) 3:00 PM - 6:00 PM
Room: Exhibit Hall
Purpose: Evaluate the quality of lung SBRT treatment plans using the Analytical Hierarchy Process (AHP) to broaden the criteria considered to include non-traditional metrics.
Methods: Two sets of 2 different right lung SBRT treatment plans with a prescription dose of 50Gy in 4 fractions were presented as alternatives with PTV located at the top of the right lung semi-peripheral, 2 cm away from bronchial tree. Eleven participants were surveyed from different institutions across the United States, Mexico and Brazil: six radiation oncologists, 3 physicists and 2 dosimetrists. Criteria analyzed was: OAR parameters based on TG-101 and RTOG 0813 lung SBRT dose tolerances, dose fall off, dose parameters and plan complexity.
Results: Radiation oncologists ranked dose parameters as the most important quality parameter by 39%, with Dmax leading at 47%. Physicists and dosimetrists ranked plan complexity as the most important quality parameter by 60% and 62% respectively; number of iterations leading at 33% for the physicists, and number of constraints, number of beams/arcs and monitor units ranking equally at 23%. The American and Brazilian cohorts placed a higher priority on plan complexity by 43% and 68% respectively, number of iterations being leading by 26% and 39%, respectively. Their Mexican counterparts chose placed a higher priority on dose parameters by 36% with heterogeneity index leading at 50%.
Conclusion: There is a wide range of plan quality preferences and this can vary at the international, national, and even institutional level. Both country of practice and role in the treatment planning process can affect plan quality preferences. For evaluating quality of lung SBRT plans, it's necessary to broaden the criteria considered to include factors that, although hard to quantify, provide a more exhaustive analysis of plan quality. AHP appears to be a unique tool to structure and analyze treatment plan quality.
Funding Support, Disclosures, and Conflict of Interest: Amy Brito Delgado acknowledges the National Council of Science and Technology of Mexico (CONACYT) for her doctoral fellowship (Fellow No. 216750).
Keywords
Taxonomy
TH- External beam- photons: extracranial stereotactic/SBRT
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