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1.
Med Phys ; 38(7): 4141-6, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21859015

RESUMO

PURPOSE: Breathing control is crucial to ensuring the accuracy of stereotactic irradiation for lung cancer. This study monitored respiration in patients with inoperable nonsmall-cell lung cancer using a respiration-monitoring apparatus, Abches, and investigated the reproducibility of tumor position in these patients. METHODS: Subjects comprised 32 patients with nonsmall-cell lung cancer who were administered stereotactic radiotherapy under breath-holding conditions monitored by Abches. Computed tomography (CT) was performed under breath-holding conditions using Abches (Abches scan) for treatment planning. A free-breathing scan was performed to determine the range of tumor motions in a given position. After the free-breathing scan, Abches scan was repeated and the tumor position thus defined was taken as the intrafraction tumor position. Abches scan was also performed just before treatment, and the tumor position thus defined was taken as the interfraction tumor position. To calculate the errors, tumor positions were compared based on Abches scan for the initial treatment plan. The error in tumor position was measured using the BrainSCAN treatment-planning device, then compared for each lung lobe. RESULTS: Displacements in tumor position were calculated in three dimensions (i.e., superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) dimensions) and recorded as absolute values. For the whole lung, average intrafraction tumor displacement was 1.1 mm (L-R), 1.9 mm (A-P), and 2.0 mm (S-I); the average interfraction tumor displacement was 1.1 mm (L-R), 2.1 mm (A-P), and 2.0 mm (S-I); and the average free-breathing tumor displacement was 2.3 mm (L-R), 3.5 mm (A-P), and 7.9 mm (S-I). The difference between using Abches and free breathing could be reduced from approximately 20 mm at the maximum to approximately 3 mm in the S-I direction for both intrafraction and interfraction positions in the lower lobe. In addition, maximum intrafraction tumor displacement with the use of Abches was 4.5 mm (S-I) in the lingular segment. These results suggest that use of the Abches system can reduce deviations in tumor position to levels below those achieved under free breathing, irrespective of the tumor location. CONCLUSIONS: Respiratory control with high accuracy and reproducibility is required for high-precision radiotherapy of inoperable nonsmall-cell lung cancer and was achieved using Abches in this study.


Assuntos
Artefatos , Neoplasias Pulmonares/fisiopatologia , Neoplasias Pulmonares/cirurgia , Radiocirurgia/métodos , Mecânica Respiratória , Técnicas de Imagem de Sincronização Respiratória/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Movimento (Física) , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
2.
Parasitol Int ; 55(3): 201-6, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16807078

RESUMO

Sweetfish, Plecoglossus altivelis, obtained from 18 rivers in Shizuoka Prefecture were examined for metacercarial infection of 2 flukes, Metagonimus yokogawai and Metagonimus miyatai. The infection rate and density of metacercariae in the fish were higher in eastern and western regions than in central region of the prefecture. After infection of hamsters with metacercariae derived from the scale, 98.7% of the adult worms obtained from the intestine was found to be M. miyatai. Conversely, from infection with metacercariae from the flesh, 90.0% of the worms was M. yokogawai. Since the worms had no exclusivity in the tissues, we conclude that the flukes have location preference with the former primarily preferring the scale, and the latter the flesh. Fish from two rivers located in adjacent areas in the western region had relatively a higher ratio of M. yokogawai in the scale relative to other rivers, suggesting an intraspecific genetic variation due to geographical isolation. On examination of adult worms in the hamster's intestine, M. yokogawai was mainly located towards the anterior part of the intestine, unlike M. miyatai, suggesting that in mammalian host too, the parasites have site preference.


Assuntos
Doenças dos Peixes/parasitologia , Heterophyidae/fisiologia , Intestinos/parasitologia , Salmoniformes/parasitologia , Infecções por Trematódeos/parasitologia , Infecções por Trematódeos/veterinária , Animais , Cricetinae , Heterophyidae/isolamento & purificação , Interações Hospedeiro-Parasita , Japão , Rios/parasitologia , Salmoniformes/anatomia & histologia
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