RESUMO

Using Monte Carlo simulation and a realistic patient model, it is shown that the volume of healthy tissue irradiated at therapeutic doses can be drastically reduced using a combination of standard megavoltage and kilovoltage X-ray beams with a contrast agent previously loaded into the tumor, without the need to reduce standard treatment margins. Four-dimensional computed tomography images of 2 patients with a centrally located and a peripherally located tumor were obtained from a public database and subsequently used to plan robotic stereotactic body radiotherapy treatments. Two modalities are assumed: conventional high-energy stereotactic body radiotherapy and a treatment with contrast agent loaded in the tumor and a kilovoltage X-ray beam replacing the megavoltage beam (contrast-enhanced radiotherapy). For each patient model, 2 planning target volumes were designed: one following the recommendations from either Radiation Therapy Oncology Group (RTOG) 0813 or RTOG 0915 task group depending on the patient model and another with a 2-mm uniform margin determined solely on beam penumbra considerations. The optimized treatments with RTOG margins were imparted to the moving phantom to model the dose distribution that would be obtained as a result of intrafraction motion. Treatment plans are then compared to the plan with the 2-mm uniform margin considered to be the ideal plan. It is shown that even for treatments in which only one-fifth of the total dose is imparted via the contrast-enhanced radiotherapy modality and with the use of standard treatment margins, the resultant absorbed dose distributions are such that the volume of healthy tissue irradiated to high doses is close to what is obtained under ideal conditions.

Assuntos

Neoplasias Pulmonares/radioterapia , Radiocirurgia , Planejamento da Radioterapia Assistida por Computador , Radioterapia Guiada por Imagem , Relação Dose-Resposta à Radiação , Humanos , Neoplasias Pulmonares/diagnóstico , Método de Monte Carlo , Movimento (Física) , Órgãos em Risco , Intensificação de Imagem Radiográfica , Radiocirurgia/métodos , Dosagem Radioterapêutica , Radioterapia Guiada por Imagem/métodos , Resultado do Tratamento

RESUMO

A collaborative research initiative was proposed by the Federation of Cooperatives of Ostrich Producers of Southeastern Brazil (FECOAVESTRUZ-Sudeste) and Embrapa Environment to training technicians and to develop environmental management procedures in order to establish criteria for the definition of 'Terms of Reference' for sustainable ostrich production for FECOAVESTRUZ associates. Eight farms with different scales of operation were selected by FECOAVESTRUZ-Sudeste for the application of 'integrated environmental indicator systems', designed to develop Environmental Management Reports and to propose best management practices in the farms. The results showed that, in general, indicators relative to Use of inputs and resources, Use of veterinary inputs and raw-materials, and especially Use of energy tended to generate negative impact, because ostrich production was intensive in these farms. On the other hand, this intensive production was also associated with improvements in Income generation and Management and administration, with positive reflexes on Employment quality and Customer respect. The utilization of the 'integrated environmental indicator systems' provide fast and inexpensive procedures designed to prepare producers for the eco-certification and ensuing sustainable origin denomination for ostrich production.

RESUMO

A collaborative research initiative was proposed by the Federation of Cooperatives of Ostrich Producers of Southeastern Brazil (FECOAVESTRUZ-Sudeste) and Embrapa Environment to training technicians and to develop environmental management procedures in order to establish criteria for the definition of 'Terms of Reference' for sustainable ostrich production for FECOAVESTRUZ associates. Eight farms with different scales of operation were selected by FECOAVESTRUZ-Sudeste for the application of 'integrated environmental indicator systems', designed to develop Environmental Management Reports and to propose best management practices in the farms. The results showed that, in general, indicators relative to Use of inputs and resources, Use of veterinary inputs and raw-materials, and especially Use of energy tended to generate negative impact, because ostrich production was intensive in these farms. On the other hand, this intensive production was also associated with improvements in Income generation and Management and administration, with positive reflexes on Employment quality and Customer respect. The utilization of the 'integrated environmental indicator systems' provide fast and inexpensive procedures designed to prepare producers for the eco-certification and ensuing sustainable origin denomination for ostrich production.