Use of an in-house Monte Carlo platform to assess the clinical impact of algorithm-related dose differences on DVH constraints. (October 2017)

• Record Type: Journal Article
• Authors: Wagner, A.; Crop, F.; Mirabel, X.; Tailly, C.; Reynaert, N.
• Is Part Of: Physica medica. Volume 42(2017)
• Page Start: 319
• Page End: 326
• Publication Date: 2017-10
• Subjects: Treatment planning -- Monte Carlo -- QA -- Dose constraints; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2017.05.062
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: A semi-automated validation module for advanced radiotherapy is introduced. The system is integrated in the Moderato Monte Carlo dose re-calculation platform. The module was tested on 27 Cyberknife and 56 Tomotherapy cases. Clinically relevant dose deviations were detected for spine and head and neck cases. The system offers perspectives in the clinical workflow and in the research field. Abstract: Purpose: The aim of the present work is to evaluate a semi-automatic prescription and validation system of treatment plans for complex delivery techniques, integrated in a Monte Carlo platform, and to investigate the clinical impact of dose differences due to the calculation algorithms, by assessing the changes in DVH constraints. Methods: A new prescription module was implemented into the Moderato system, an in-house Monte Carlo platform, with corresponding dose constraints generated depending on the anatomical region and fractionation scheme considered. The platform was tested on 83 cases treated with Cyberknife and Tomotherapy machines, to assess whether dose variations between the re-calculated dose and the Treatment Planning System might impact the dose constraints on the sensitive structures. Results: Dose differences were small (within 3%) between calculation algorithms in most of the thoracic, pelvic and abdominal cases, both for the Cyberknife and Tomotherapy machines. On the other hand, spinal and head and neck treatments presented a few significant dose deviations for constraints on small volumes, such as the optic pathways and the spinal cord. These differences range from −11% to +6%, inducing constraint violations of up to 8% over the dose limit. Conclusions: The Moderato platform offers an interesting tool for plan quality validation, with a prescription module highlighting crucial features in the structures list, and a Monte Carlo dose re-calculation for complex modern techniques. Due to the high number of warnings appearing in some situations, display optimization is required in practice.