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WE‐AB‐209‐04: Biological Evaluation of Universal Multi‐Criteria Optimization VMAT Prostate Plans
Author(s) -
Guerrero M,
Chen S
Publication year - 2016
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4957773
Subject(s) - rectum , prostate cancer , medicine , nuclear medicine , prostate , medical physics , cancer , surgery
Purpose: In recent years Multi‐Criteria Optimization (MCO) has become commercially available as a potential optimization method for intensity modulated and volumetric arc therapies (IMRT and VMAT). The purpose of our work is to develop a universal set of objectives and constraints to generate prostate cancer MCO plans with VMAT and evaluate them using biological metrics. Methods: We randomly selected ten prostate plans (two‐arc VMAT) for patients with intermediate risk prostate cancer prescribed 75.6–79.2Gy to the prostate and seminal vesicles. We compared the plan scores to our clinical plans generated with standard IMRT optimization techniques. The planning target volumes (PTV) were 5–10 mm set‐up margin expansion of the gross target volume. Using the same two arcs we generated MCO plans with a standard set of constraints and objectives using Raystation v4.5. The dose‐volume histograms (DVH) for the (PTV), rectum and bladder were exported and used to calculate tumor control probability (TCP) and the complication‐free tumor control probability P+ using biological models from the literature. We classified the plans by their level of difficulty based on the rectum‐PTV overlap and develop MCO plans with similar levels of conformality as the clinical plans. Results: The P+ values of the MCO plans had an average of 86.4%±2.3% and were equivalent to the clinical plans (P+ average of 85.0%±2.1%, p‐value=0.33). The MCO NTCP values for the rectum ranged from 0.7% to 20% and were highly correlated with rectum‐PTV overlap. NTCP values for the bladder were less than 1% for all MCO plans. Conclusion: MCO VMAT prostate plans obtained with standardized objectives and constraints generate biologically equivalent plans to the clinical plans generated with standard optimization techniques.