ABSTRACT
A redundant independent dosimetric calculation (RIDC) prior to treatment has become a basic part of the QA process for 3D conventional radiotherapy, and is strongly recommended in several international publications. On the other hand, the rapid growth in the number of intensity modulated treatments has led to a significant increase in the workflow associated with QA treatments. Diamond ("K&S Associates") is RIDC software which is capable of calculating VMAT (Volumetric Modulated Arc Therapy) fields. Modeling, validation and commissioning are necessary steps thereby making it a useful tool for VMAT QA. In this paper, a procedure for the validation of the calculation algorithm is demonstrated. A set 3D conventional field was verified in two ways: firstly, a comparison was made between Diamond calculations and experimental measures obtaining an average deviation of -0.1 ± 0.7%(1SD), and secondly, a comparison made between Diamond and the treatment planning system (TPS) Eclipse, obtaining an average deviation of 0.4 ± 0.8%(1SD). For both steps, a plastic slab phantom was used. VMAT validation was carried out by analyzing 59 VMAT plans in two ways: first, Diamond calculation versus experimental measurement with an average deviation of -0.2 ± 1.7%(1SD), and second, Diamond calculation versus TPS calculation with an average deviation of 0.0 ± 1.6%(1SD). In this phase a homogeneous cylindrical phantom was used. These results led us to consider this calculation algorithm validated for use in VMAT verifications.
Subject(s)
Radiotherapy, Intensity-Modulated/methods , Software , Radiometry , Radiotherapy DosageABSTRACT
Aún no ha sido establecido si las pacientes con cáncer de mama con un tumor primario menor o igual a 5 cm y con 1 a 3 ganglios axilares afectos en el momento del diagnóstico se beneficiarían de radioterapia postmastectomía. La radioterapia moderna ha demostrado su utilidad en pacientes con alto riesgo de recidiva local tanto en términos de mejor control loco-regional como en aumento de la supervivencia. Pero en el grupo de pacientes con riesgo moderado (pT1-2 N1 y 1 a 3 ganglios positivos) los ensayos aleatorizados están aún en marcha y no se espera obtener las primeras conclusiones en al menos diez años. La decisión de tratamiento se debería basar en el conocimiento del comportamiento biológico del cáncer de mama y en la evidencia científica acumulada. Revisamos extensamente ambos aspectos y concluimos que los pacientes en esta categoría tienen un beneficio en el control loco-regional que podría traducirse en mejor supervivencia en algunos subgrupos (AU)
Subject(s)
Female , Humans , Mastectomy , Radiotherapy/methods , Breast Neoplasms/radiotherapy , Breast Neoplasms/surgery , Risk Factors , Disease-Free Survival , Prognosis , Risk Assessment , Evidence-Based Medicine , Cost-Benefit Analysis , Neoplasm Recurrence, Local/prevention & controlABSTRACT
Postcystectomy radiotherapy has not been analyzed profoundly for several reasons: the local recurrence rate is low; it has been used exclusively preoperatively since the first cooperative clinical trials were conducted; a high incidence of intestinal obstruction has been reported. The tumors that can benefit from coadjuvant radiotherapy, particularly those with a higher risk of local recurrence, are analyzed.
