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1.
Clin Oncol (R Coll Radiol) ; 35(4): 227-236, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36609026

RESUMO

AIM: To carry out a comprehensive critical appraisal of image-guided intensity-modulated proton therapy practice for craniospinal irradiation (CSI). MATERIALS AND METHODS: An image-guided intensity-modulated proton therapy database of 45 consecutive paediatric patients with central nervous system embryonal malignancies treated between January 2019 and April 2022 were critically appraised for demography, diagnosis, treatment planning strategy and treatment delivery accuracy. RESULTS: Most patients (median age: 7.5 years; male:female ratio: 34:11) had medulloblastoma (56%), followed by recurrent ependymoma (19%), pinealoblastoma (5%), germ cell (5%) and others (15%). The dose to the planning target volume-craniospinal (PTV-CS; length 39.06-79.59 cm) varied from 21 to 35 GyRBE, whereas the combined median dose to craniospinal and boost was 54 GyRBE. In all patients, the 95% isodose line covered the cribriform plate completely and optic nerves mostly, with a median V95% of 100% and 82.96%, keeping Dmax to the lens <3.9 GyRBE. In skeletally immature patients (88.38%), the anterior vertebral body was completely covered in 18.18% and underdosed in 70.15% of the cases, resulting in a median Dmean of 10.11 GyRBE to the oesophagus. Lateral spine coverage was maintained on the edges of the vertebral body in 52.2%, whereas it extended beyond in 48.8%. The median V98% for clinical target volumes and V95% for PTVs of the brain, spine and craniospinal were >97%, with excellent conformity (0.89) and homogeneity (0.07) indices for PTV-CS. All neurological organs at risk received a median Dmax ranging from 36 to 44 GyRBE from the combined CSI and boost regimens. Analysis of patient-specific quality assurance results revealed that 545 (97.67%) planar dosage verification had gamma (3% at 3 mm) values >95%. The online patient set-up verification showed translational and rotational deviation within 2 mm and 0.5° in 88-94% and 97% of the cases. Systematic and random error were within 0.90 mm and 1.71 mm in translation and 0.1° and 0.2° in rotation. CONCLUSION: A change in practice pattern was observed. The findings from our comprehensive critical appraisal add to the growing library of CSI practice and may serve as a reference for inter-institutional comparison.


Assuntos
Neoplasias do Sistema Nervoso Central , Neoplasias Cerebelares , Neoplasias Embrionárias de Células Germinativas , Terapia com Prótons , Radioterapia de Intensidade Modulada , Humanos , Criança , Masculino , Feminino , Terapia com Prótons/métodos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Neoplasias do Sistema Nervoso Central/diagnóstico por imagem , Neoplasias do Sistema Nervoso Central/radioterapia , Neoplasias Embrionárias de Células Germinativas/radioterapia
2.
Opt Lett ; 44(12): 3134-3137, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31199399

RESUMO

Highly reproducible and precisely controlled gradual variation in optical reflectivity or electrical resistance between amorphous and crystalline phases of phase change (PC) material is a key requirement for multilevel programming. Here we report high-contrast multilevel set and reset operations through accumulative switching in growth-dominated AgInSbTe PC material using a nanosecond laser-based pump-probe technique. The precise tuning of fractions of crystallized or re-amorphized region is achieved by means of controlling the number of irradiated laser pulses enabling six stable multilevels with high-reflectivity contrast of 2% between any two states. Furthermore, Raman spectra of irradiated spots validate the structural changes involved during multilevel switching between amorphous and crystalline phases.

3.
J Environ Manage ; 79(2): 188-97, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16202505

RESUMO

We evaluated the conservation attitudes of the local villagers living adjacent to the Kalakad-Mundanthurai Tiger Reserve in southern India 6 years after implementation of a World Bank funded eco-development project. We assessed attitudes towards three facets of conservation: the tiger, an emblematic species signifying India's commitment to wildlife conservation; the forest, a principle source of fuel-wood and other products; and the Forest Department, which manages the forest. More specifically we predicted that (i) attitudes would be an effective predictor of resource use interest in the forest and (ii) benefits obtained from the EDP would create more favorable attitudes towards conservation and the protected area employees. Twelve villages located within 3 km from the reserve boundary were chosen and 2-3% of the households interviewed with regard to their attitudes towards these three facets of conservation, their household resource use patterns, wealth, sex, age and length of residency. We found significant associations between wealth, sex, age and both tiger and forest conservation. Providing benefits has not changed the underlying attitudes of the communities. The poorer sections of society, whether receiving benefits or not, tended to support tiger conservation because conserving wildlife did not affect their livelihood in any way, whereas both the rich and poor had misgivings about forest conservation due to dependency on forest products. We conclude that the eco-development project has not effectively addressed the most important of the local concerns.


Assuntos
Atitude , Conservação dos Recursos Naturais , Agricultura Florestal , Opinião Pública , Tigres/crescimento & desenvolvimento , Distribuição por Idade , Animais , Animais Selvagens/crescimento & desenvolvimento , Feminino , Humanos , Índia , Masculino , Pobreza , Características de Residência , População Rural , Distribuição por Sexo , Classe Social , Inquéritos e Questionários
4.
Clin Chim Acta ; 362(1-2): 49-56, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16198326

RESUMO

BACKGROUND: Plasma lipoproteins are protected against oxidative modification by the antioxidant defense system. An imbalance in the antioxidant defense system seems to result from the accumulation of low density lipoprotein (or) very low density lipoprotein in the course of hyperlipidemia. METHODS: The lipid profile, glycoprotein components, glucose, total proteins, albumin, lipid peroxidation and antioxidant status of plasma and erythrocytes were investigated in hyperlipidemic patients and hyperlipidemic patients with diabetes on treatment with glibenclamide (or) glipizide along with normal subjects and compared. RESULTS: A significant increase was observed in the levels of total cholesterol (TC), VLDL-C, triglycerides (TG), lipid peroxidation, ceruloplasmin (CP), glycoprotein components and glucose in the hyperlipidemic patients with/without diabetes and the increase was more pronounced (except TC) in patients with diabetes. The activities of erythrocyte antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and plasma concentrations of vitamins C and E, and reduced glutathione (GSH) decreased in hyperlipidemic patients with/without diabetes. GPx, CAT, vitamin C and GSH levels exhibited a further decrease in hyperlipidemic patients with diabetes. CONCLUSION: An enhanced levels of VLDL-C, TC/HDL-C ratio, TG, lipid peroxidation, glycoprotein components, and decreased concentrations of total proteins (TPs) and albumin were observed in hyperlipidemic patients with diabetes while the decrease was more marked in GSH, vitamin C, CAT and GPx among antioxidants.


Assuntos
Antioxidantes/metabolismo , Diabetes Mellitus/sangue , Glicoproteínas/sangue , Hiperlipidemias/sangue , Hiperlipidemias/complicações , Lipídeos/sangue , Oxidantes/sangue , Adulto , Idoso , Antioxidantes/análise , Humanos , Pessoa de Meia-Idade
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