Dose distributions of high-precision radiotherapy treatment: A comparison between the CyberKnife and TrueBeam systems

Background: several high-precision stereotactic radiation therapy modalities are currently used in clinical settings. We aimed to evaluate whether the CyberKnife [CK] or TrueBeam [TB] radiation treatment systems were more appropriate for treating targets of various morphologies according to the physical properties of each device

Materials and Methods: spheres [diameter = 5-50 mm], as well as triangular prisms and cubes [length of a side = 10-50 mm], were used as virtual targets for each treatment delivery system. A phantom with dosimetry film was irradiated to evaluate the flatness and gradient of the radiation treatment from each modality

Results: the homogeneity index [HI] for the spherical targets was significantly higher [dose distribution was more homogeneous] using the TB than when using the CK [1.9 vs. 1.4; p = 0.002]. There were no significant differences between treatment modalities in the HI for more complex shapes. The HI increased monotonically as the virtual target diameter increased for the CK [p = 0.048]. The flatness parameter was lower for the TB than for the CK [1.4 vs. 1.1; p < 0.001]

Conclusion: the CK is particularly robust for delivering therapeutic radiation to small targets, while the TB is more suitable for targets with a simple shape or when the HI is a critical treatment factor

Long absence from work due to sickness among psychiatric outpatients in Japan, with reference to a recent trend for perfectionism

Sick leave from work due to psychiatric disorders is a major public health problem, not only in Japan but also worldwide. As males and females in Japan tend to differ in their approach to work, a gender difference in perfectionism might be expected. We investigated the background factors leading to long-term absence from work due to sickness among psychiatric outpatients in Japan. We surveyed 73 psychiatric outpatients who were absent from work for a long time [POAWs] and 228 employees without long-term sickness absence as controls. GHQ-30, NEO-FFI, MPS, RSS and questionnaires inquiring about background factors, including relationships with others, was used, and the data were compared between males and females. Male POAWs had a significantly higher tendency for depression and perfectionism than the controls, but in females this difference was not significant. With regard to personal relationships of POAWs, males had worse relationships with superiors and colleagues, whereas females had worse relationships with superiors, colleagues, and family. The data suggested that male workers exhibiting perfectionism tend to undertake too much work and become exhausted when frying to cope with complex human relationships in the workplace. Female workers having the double burden of family commitment and perfectionism tend to be isolated in terms of personal relationships, leading to exhaustion both in and outside the workplace

Caninos não irrompidos - alternativas de tratamento / Impacted canine - treatment alternatives

A não irrupção do dente canino permanente maxilar é um sério problema que ocorre com certa freqüência, o que justifica o diagnóstico e a intervenção assim que possível, e pode ser diagnosticada por meio do exame de palpação para sentir-se a saliência do canino em desenvolvimento e por exames radiográficos pelos quais verifica-se o posicionamento do dente. Quando não houve erupção espontânea, deverão ser usados métodos ativos, como cirurgia acompanhada de tração com dispositivos ortodônticos. Freqüentemente o canino não irrompe porque nem sempre encontra um corredor de erupção adequado para alinhar-se ao lateral e primeiro pré-molar; este podendo irromper parcialmente ou ficar mal posicionado - localizando-se ectopicamente na face vestibular ou no palato - ou não irromper e ficar intra-ósseo em posições variadas. Se houver um corredor de erupção adequado, o canino pode irromper naturalmente e, se isso não ocorrer, a exposição cirúrgica e o tracionamento devem ser utilizados para orientar sua direção de erupção. Uma visão tridimensional auxilia no diagnóstico das causas que retardam ou impedem sua erupção. Quando o espaço para o canino no arco é suficiente - e mesmo sendo tracionado ele não erupciona - pode-se estar diante de uma anquilose alveolo-dentária. Nesse último caso uma manobra para trazer o dente à sua posição seria o transplante autógeno ou reimplante antes da exodontia definitiva. O controle pós-operatório e a colaboração do paciente são importantes para o sucesso do tratamento. O paciente e seus pais devem estar cientes do prognóstico do tratamento e dos fatores de risco e conseqüências de um canino não-irrompido