Artigo de peri??dico
Mechanical evaluation of the Bravos afterloader system for HDR brachytherapy
Registro en:
1538-4721
6
18
10.1016/j.brachy.2019.06.005
24.141
53.00
Autor
BELLEZZO, MURILLO
BAEZA, JOSE A.
VONCKEN, ROBERT
RENIERS, BRIGITTE
VERHAEGEN, FRANK
FONSECA, GABRIEL P.
Resumen
PURPOSE: The Bravos afterloader system was released by Varian Medical Systems in October of
2018 for high-dose-rate brachytherapy with 192Ir sources, containing new features such as the
CamScale (a new device for daily quality assurance and system recalibration), channel length verification,
and different settings for rigid and flexible applicators. This study mechanically evaluated
the Bravos system precision and accuracy for clinically relevant scenarios, using dummy sources.
METHODS AND MATERIALS: The system was evaluated after three sets of experiments: (1)
The CamScale was used to verify inter- and intra-channel dwelling variability and system calibration;
(2) A high-speed camera was used to verify the source simulation cable movement inside a
transparent quality assurance device, where dwell positions, dwell times, transit times, speed profiles,
and accelerations were measured; (3) The source movement inside clinical applicators was
captured with an imaging panel while being exposed to an external kV source. Measured and
planned dwell positions and times were compared.
RESULTS: Maximum deviations between planned and measured dwell positions and times for the
source cable were 0.4 mm for the CamScale measurements and 0.07 seconds for the high-speed
camera measurements. Mean dwell position deviations inside clinical applicators were below
1.2 mm for all applicators except the ring that required an offset correction of 1 mm to achieve
a mean deviation of 0.4 mm.
CONCLUSIONS: Features of the Bravos afterloader system provide a robust and precise treatment
delivery. All measurements were within manufacturer specifications. Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq) CNPq: 200402/2015-3