Prediction models as decision-support tools for virtual patient-specific quality assurance of helical tomotherapy plans.

Background and purpose: Prediction models may be reliable decision-support tools to reduce the workload associated with the measurement-based patient-specific quality assurance (PSQA) of radiotherapy plans. This study compared the effectiveness of three different models based on delivery parameters, complexity metrics and sinogram radiomics features as tools for virtual-PSQA (vPSQA) of helical tomotherapy (HT) plans. Materials and methods: A dataset including 881 RT plans created with two different treatment planning systems (TPSs) was collected. Sixty-five indicators including 12 delivery parameters (DP) and 53 complexity metrics (CM) were extracted using a dedicated software library. Additionally, 174 radiomics features (RF) were extracted from the plans' sinograms. Three groups of variables were formed: A (DP), B (DP + CM) and C (DP + CM + RF). Regression models were trained to predict the gamma index passing rate P R γ (3%G, 2mm) and the impact of each group of variables was investigated. ROC-AUC analysis measured the ability of the models to accurately discriminate between 'deliverable' and 'non-deliverable' plans. Results: The best performance was achieved by model C which allowed detecting around 16% and 63% of the 'deliverable' plans with 100% sensitivity for the two TPSs, respectively. In a real clinical scenario, this would have decreased the whole PSQA workload by approximately 35%. Conclusions: The combination of delivery parameters, complexity metrics and sinogram radiomics features allows for robust and reliable PSQA gamma passing rate predictions and high-sensitivity detection of a fraction of deliverable plans for one of the two TPSs. Promising yet improvable results were obtained for the other one. The results foster a future adoption of vPSQA programs for HT.

Updating a clinical Knowledge-Based Planning prediction model for prostate radiotherapy.

BACKGROUND AND PURPOSE: Clinical knowledge-based planning (KBP) models dedicated to prostate radiotherapy treatment may require periodical updates to remain relevant and to adapt to possible changes in the clinic. This study proposes a paired comparison of two different update approaches through a longitudinal analysis. MATERIALS AND METHODS: A clinically validated KBP model for moderately hypofractionated prostate therapy was periodically updated using two approaches: one was targeted at achieving the biggest library size (Mt), while the other one at achieving the highest mean sample quality (Rt). Four subsequent updates were accomplished. The goodness, robustness and quality of the outcomes were measured and compared to those of the common ancestor. Plan quality was assessed through the Plan Quality Metric (PQM) and plan complexity was monitored. RESULTS: Both update procedures allowed for an increase in the OARs sparing between +3.9 % and +19.2 % compared to plans generated by a human planner. Target coverage and homogeneity slightly reduced [-0.2 %;-14.7 %] while plan complexity showed only minor changes. Increasing the sample size resulted in more reliable predictions and improved goodness-of-fit, while increasing the mean sample quality improved the outcomes but slightly reduced the models reliability. CONCLUSIONS: Repeated updates of clinical KBP models can enhance their robustness, reliability and the overall quality of automatically generated plans. The periodical expansion of the model sample accompanied by the removal of the unacceptable low quality plans should maximize the benefits of the updates while limiting the associated workload.

Analysis of clinical patient-specific pre-treatment quality assurance with the new helical tomotherapy platform, following the AAPM TG-218 report.

PURPOSE: This study presents patient-specific quality assurance (QA) results from the first 395 clinical cases for the new helical TomoTherapy® platform (Radixact) coupled with dedicated Precision TPS. METHODS: The passing rate of the Gamma Index (GP%) of 395 helical QA of patient-specific tomotherapy, acquired with ArcCHECK, is presented, analysed and correlated to various parameters of the plan. Following TG-218 recommendations, the clinic specific action limit (ALcs) and tolerance limit (TLcs) were calculated for our clinic and monitored during the analysed period. RESULTS: The mean values ​​(± 1 standard deviation) of GP% (3%/2 mm) (both global and local normalization) are: 97.6% and 90.9%, respectively. The proposed ALcs and TLcs, after a period of two years' process monitoring are 89.4% and 91.1% respectively. CONCLUSIONS: The phantom measurements closely match the planned dose distributions, demonstrating that the calculation accuracy of the new Precision TPS and the delivery accuracy of the Radixact unit are adequate, with respect to international guidelines and reports. Furthermore, a first correlation with the planning parameters was made. Action and tolerance limits have been set for the new Radixact Linac.

[Health education: perceptions of professionals working in a Regional Health Office]. / Educaçáo em saúde: percepção de profissionais atuantes em uma Coordenadoria Regional de Saúde.

The aim of this study is to analyze the perceptions of professionals working in a Regional Health Office in Health Education. This is a qualitative exploratory-descriptive study. Interviews were held with eight professionals from the state public sector, responsible for implementing public health policies. For analysis we used analyzing thematic content methodology. The results were discussed based on proposals of Paulo Freire. It was noted that health professionals have different perceptions regarding questions related to education and health education, and their educational practices are supported by the traditional system. The situation callsfor a change, which includes unifying concepts and building a new educational praxis, reviewing practices at all times and incorporating new knowledge to guide the construction of a new model of health.

Educação em saúde: percepção de profissionais atuantes em uma Coordenadoria Regional de Saúde / Educación en salud: percepciones de profesionales actuantes en un Coordinadora Regional de Salud / Health education: perceptions of professionals working in a Regional Health Office

O objetivo do estudo é analisar a percepção dos profissionais atuantes em uma Coordenadoria Regional de Saúde sobre a Educação em Saúde. Trata-se de uma pesquisa qualitativa do tipo exploratório-descritiva. Foi realizada uma entrevista com oito profissionais do setor público estadual, responsáveis pela implementação das políticas públicas de saúde. Para análise foi usado o método análise de conteúdo do tipo temática. Os resultados foram discutidos com base nas propostas de Paulo Freire. Observou-se que os profissionais de saúde detêm percepções diferenciadas no que tange questões que permeiam a educação e educação em saúde, tendo suas práticas educacionais pautadas no sistema tradicional. Assim, é necessária uma mudança neste contexto, unificando conceitos e construindo uma nova práxis educacional, fazendo rever as práticas a todo o momento e incorporando novos saberes pautados na construção de um novo modelo de saúde.

El objetivo es analizar las percepciones de los profesionales que trabajan en Salud Regional de Educación en Salud Este es un salto cualitativo exploratorio-descriptivo. Se realizaron entrevistas con ocho profesionales del sector público estatal, encargada de ejecutar las políticas públicas de salud. Para el análisis se utilizó el método de análisis de contenido temático. Los resultados fueron discutidos con base en las propuestas de Paulo Freire. Se señaló que los profesionales de la salud tienen percepciones diferentes sobre cuestiones relacionadas con la educación la educación y la salud, y sus prácticas educativas soportadas por el sistema tradicional. Esto requiere un cambio en este contexto, la unificación de conceptos y la construcción de una nueva praxis educativa, haciendo una reseña de las prácticas en todo momento y la incorporación de nuevos conocimientos guiado la construcción de un nuevo modelo de salud.

The aim of this study is to analyze the perceptions of professionals working in a Regional Health Office in Health Education.This is a qualitative exploratory-descriptive. Interviews were held with eight professionals from the state public sector, responsible for implementing public health policies. For analysis we used the method analyzing thematic content. The results were discussed based on proposals of Paulo Freire. It was noted that health professionals have different perceptions regarding questions related to education and health education, and their educational practices supported by the traditional system. This requires a change in this context, unifying concepts and building a new educational praxis, making review the practices at all times and incorporating new knowledge guided the construction of a new model of health.