Open AccessEvaluation of complexity and deliverability of prostate cancer treatment plans designed with a knowledge‐based VMAT planning technique
Author(s) -
Wall Phillip D. H.,
Fontenot Jonas D.
Publication year - 2020
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12790
Subject(s) - medicine , radiation treatment planning , nuclear medicine , radiation therapy , metric (unit) , prostate , medical physics , computer science , cancer , surgery , operations management , economics
Purpose Knowledge‐based planning (KBP) techniques have been reported to improve plan quality, efficiency, and consistency in radiation therapy. However, plan complexity and deliverability have not been addressed previously for treatment plans guided by an established in‐house KBP system. The purpose of this work was to assess dosimetric, mechanical, and delivery properties of plans designed with a common KBP method for prostate cases treated via volumetric modulated arc therapy (VMAT). Methods Thirty‐one prostate patients previously treated with VMAT were replanned with an in‐house KBP method based on the overlap volume histogram. VMAT plan complexities of the KBP plans and the reference clinical plans were quantified via monitor units, modulation complexity scores, the edge metric, and average leaf motion per degree of gantry rotation. Each set of plans was delivered to the same diode array and agreement between computed and measured dose distributions was evaluated using the gamma index. Varying percent dose‐difference (1–3%) and distance‐to‐agreement (1 mm to 3 mm) thresholds were assessed for gamma analyses. Results Knowledge‐based planning (KBP) plans achieved average reductions of 6.4 Gy ( P < 0.001) and 8.2 Gy ( P < 0.001) in mean bladder and rectum dose compared to reference plans, while maintaining clinically acceptable target dose. However, KBP plans were significantly more complex than reference plans in each evaluated metric ( P < 0.001). KBP plans also showed significant reductions ( P < 0.05) in gamma passing rates at each evaluated criterion compared to reference plans. Conclusions While KBP plans had significantly reduced bladder and rectum dose, they were significantly more complex and had significantly worse quality assurance outcomes than reference plans. These results suggest caution should be taken when implementing an in‐house KBP technique.