ABSTRACT
The Accurate dosage prediction in Radiation Therapy is challenging, prompting a need for precision beyond conventional clinical Treatment Planning Systems (TPS). Monte Carlo-based methods are sought for their superior accuracy. The aim of this study is to compare dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, focusing on smaller fields. This study was initiated with a homogeneous validation of the TrueBeam STX system, using measurements obtained from the Centre Hospitalier Interregional Edith Cavell (CHIREC) in Brussels. The validation compared dosimetric functions (Percentage Depth Dose (PDD), Dose profile (DP) and Collimator scatter fraction (CSF)) employing the GAMMA index with a 2% / 2 mm criterion tolerance. Following this, heterogeneous studies examined dose distributions between the ACUROS algorithm and the GATE platform in various tissue densities and field sizes, with a specific focus on smaller fields. Simulations were conducted using both platforms on chest phantoms with heterogeneous slabs representing bone, lung, and heart, each housing a central tumor. The impact of electronic equilibrium on tumors for different small field sizes was evaluated. Results showed a remarkable 99% agreement between measurements and GATE calculations in the homogeneous validation of the TrueBeam STX system. However, in heterogeneous studies, ACUROS consistently overestimated lung doses by up to 8% compared to GATE simulation, especially evident with a flattening filter and smaller beam sizes at density interfaces. This highlights significant dose estimation discrepancies between ACUROS and GATE, emphasizing the need for precise calculations. The findings support exploring Monte Carlo-based methods for enhanced accuracy in Radiation Therapy treatment planning.
Subject(s)
Radiometry , Radiotherapy Planning, Computer-Assisted , Radiotherapy Planning, Computer-Assisted/methods , Computer Simulation , Algorithms , LungABSTRACT
Mature ovarian teratoma is the most frequent benign tumor in premenopausal women. It is usually asymptomatic but complications are possible such as adnexal torsion, infection, malignant transformation or cystic rupture. The latter can be spontaneous or more often occurs during surgery of excision of dermoid cyst. It can rarely result in chemical peritonitis, which is due to the irritation of the peritoneal serosa by the aseptic content of the tumour. We report the case of a patient who undrewent an emergency laparotomy for a chemical peritonitis following a spontaneous rupture of a dermoid cyst. Afterwards, she developed an acute respiratory distress syndrome that required an admission in the intensive care unit and subsequent surgery.
Le tératome mature de l'ovaire est la tumeur ovarienne bénigne la plus fréquente chez la femme en pré-ménopause. Le plus souvent, il est asymptomatique, mais il peut se compliquer par une torsion annexielle, une infection, une dégénérescence maligne ou une rupture kystique. Celle-ci peut être spontanée ou, plus souvent, survenir lors d'une chirurgie d'exérèse du kyste. Rarement, elle peut entraîner une péritonite chimique. Celle-ci est consécutive à l'irritation de la séreuse péritonéale par le contenu aseptique da la tumeur. Nous rapportons ici le cas d'une patiente opérée en urgence pour une péritonite chimique suite à une rupture spontanée d'un kyste dermoïde. Dans les suites opératoires, la patiente a développé un syndrome de détresse respiratoire aigu qui a nécessité une prise en charge aux soins intensifs et une nouvelle intervention chirurgicale.
