RESUMEN
Volumetric modulated arc therapy (VMAT) and 3D dynamic conformal arc therapy (DCAT) are 2 methods proven useful for the clinical implementation of stereotactic body radiation therapy (SBRT) for lung lesions however, similar comparisons of SBRT liver lesions are lacking. The purpose of this study was to determine if the conformity of dose, irradiated volume, and dose to organs at risk (OAR) are equivalent or improved with the use of DCAT as an alternative treatment method when compared to standard VMAT for SBRT delivery of palliative and early-stage liver lesions. Twenty patients with liver lesions sized 2.0 to 5.0 cm were selected for this study. Plans were created with both DCAT and VMAT techniques for each patient. Metrics evaluated included the mean heart, kidney, large bowel, small bowel, esophagus, and stomach doses, the lung volume receiving 20 Gy (V20), the volume of the normal liver receiving 15 Gy (V15), conformity index (CI), heterogeneity index (HI), and the irradiated volume or volume receiving 25 Gy (V25). The p-values for the mean dose to kidneys, small bowel, esophagus, and the lung V20 were greater than 0.05, and no statistical difference could be determined between DCAT and VMAT. The p-values for the mean heart, large bowel, stomach, and liver V15 were less than 0.05, indicating statistical significance and superiority of VMAT for minimizing dose to these organs, especially V15 of the liver. The DCAT technique produced CI greater than 1.0 for all patients proving superior coverage, while standard VMAT produced significantly improved V25 with p-values less than 0.0001, and consequently higher HI.
Asunto(s)
Neoplasias Hepáticas , Radiocirugia , Radioterapia de Intensidad Modulada , Humanos , Órganos en Riesgo , Radiocirugia/métodos , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador/métodos , Radioterapia de Intensidad Modulada/métodosRESUMEN
Vibrio vulnificus is an estuarian bacterium that causes septicemia and serious wound infection. The cytolysin, one of the important virulence determinants in V. vulnificus infection, has been reported to have lethal activity primarily by increasing pulmonary vascular permeability. In the present study, we investigated the cytotoxic mechanism of V. vulnificus cytolysin in cultured pulmonary artery endothelial (CPAE) cells, which are possible target cells of cytolysin in vivo. V. vulnificus cytolysin caused the CPAE cell damages with elevation of the cytosolic free Ca2+, DNA fragmentation, and decrease of the cellular NAD+ and ATP level. These cytotoxic effects of V. vulnificus cytolysin were prevented by EGTA and aminobenzamide, but were not affected by verapamil or catalase. These results indicate that the elevation of cytosolic free Ca2+ induced by V. vulnificus cytolysin causes the increase of DNA fragmentation and the damaged DNA activates nuclear poly(ADP-ribose) synthetase, which depletes the cellular NAD+ and ATP, resulting in cell death.