Objective To develop a novel method for measuring the Hounsfield Unit(HU)value of the surface carbon fiber material of the Varian Exact IGRT Couch,and to establish a treatment couch model in the treatment planning system(TPS)for correcting the attenuation of radiation dose caused by the treatment couch.Methods Two different field combinations were used to measure the radiation dose attenuation at the thin end and the middle medium-thickness part of the Varian Exact IGRT Couch.Dose deviations were measured when radiation passed through the treatment couch or not.Multiple sets of different HU values for the couch surface materials were defined in the TPS,and the dose difference between with and without couch was calculated under the same conditions as the measurements.The HU value of the treatment couch material corresponding to the actual measurements was found by data comparison and analysis.Results The attenuation for two interpenetrating fields was-2.49%to-1.69%at the thin end,and-3.43%to-2.23%at the medium-thickness part.The attenuation for multiple oblique incident fields ranged from-3.12%to-2.17%at the thin end,and that was-3.59%to-2.86%at the medium-thickness part.When the HU values of the couch model's surface and internal materials in the TPS were defined as-500 and-960,for two interpenetrating fields,the attenuation was-2.57%to-1.53%at the thin end,and-3.28%to-2.18%at the medium-thickness part;while for multiple oblique incident fields,the attenuation was-3.12%to-2.21%at the thin ends,and-3.42%to-2.43%at the medium-thickness part.These calculated results were consistent with the actual measurement values.For 40 verification plans,the average point dose difference between measurement and calculation in TPS were 0.90%and 0.89%at the thin end and medium-thickness part,respectively.Conclusion This novel measurement method can measure the HU value of the surface carbon fiber material and internal foam material of Exact IGRT Couch.Defining the HU values of these two materials of the couch model in the TPS as-500 and-960 can correct the radiation dose attenuation caused by the treatment couch,thereby improving the dose accuracy of the target volume and organs-at-risk.

Objective To develop a novel method for measuring the Hounsfield Unit(HU)value of the surface carbon fiber material of the Varian Exact IGRT Couch,and to establish a treatment couch model in the treatment planning system(TPS)for correcting the attenuation of radiation dose caused by the treatment couch.Methods Two different field combinations were used to measure the radiation dose attenuation at the thin end and the middle medium-thickness part of the Varian Exact IGRT Couch.Dose deviations were measured when radiation passed through the treatment couch or not.Multiple sets of different HU values for the couch surface materials were defined in the TPS,and the dose difference between with and without couch was calculated under the same conditions as the measurements.The HU value of the treatment couch material corresponding to the actual measurements was found by data comparison and analysis.Results The attenuation for two interpenetrating fields was-2.49%to-1.69%at the thin end,and-3.43%to-2.23%at the medium-thickness part.The attenuation for multiple oblique incident fields ranged from-3.12%to-2.17%at the thin end,and that was-3.59%to-2.86%at the medium-thickness part.When the HU values of the couch model's surface and internal materials in the TPS were defined as-500 and-960,for two interpenetrating fields,the attenuation was-2.57%to-1.53%at the thin end,and-3.28%to-2.18%at the medium-thickness part;while for multiple oblique incident fields,the attenuation was-3.12%to-2.21%at the thin ends,and-3.42%to-2.43%at the medium-thickness part.These calculated results were consistent with the actual measurement values.For 40 verification plans,the average point dose difference between measurement and calculation in TPS were 0.90%and 0.89%at the thin end and medium-thickness part,respectively.Conclusion This novel measurement method can measure the HU value of the surface carbon fiber material and internal foam material of Exact IGRT Couch.Defining the HU values of these two materials of the couch model in the TPS as-500 and-960 can correct the radiation dose attenuation caused by the treatment couch,thereby improving the dose accuracy of the target volume and organs-at-risk.

Pulmonary drug delivery has attracted increasing attention in biomedicine, and porous particles can effectively enhance the aerosolization performance and bioavailability of drugs. However, the existing methods for preparing porous particles using porogens have several drawbacks, such as the inhomogeneous and uncontrollable pores, drug leakage, and high risk of fragmentation. In this study, a series of cyclodextrin-based metal-organic framework (CD-MOF) particles containing homogenous nanopores were delicately engineered without porogens. Compared with commercial inhalation carrier, CD-MOF showed excellent aerosolization performance because of the homogenous nanoporous structure. The great biocompatibility of CD-MOF in pulmonary delivery was also confirmed by a series of experiments, including cytotoxicity assay, hemolysis ratio test, lung function evaluation,

BACKGROUND:Human amniotic epithelial cells have some properties of stem cells, which can be induced to differentiate into corneal epithelial cells, but cannot be tracedin vitro. OBJECTIVE:To investigate the feasibility and infection efficiency of adenovirus vector carrying enhanced green fluorescent protein (EGFP) into the human amniotic epithelial cells. METHODS:The adenovirus vectors carrying EGFP was transferred into human amniotic epithelial cells culturedin vitro. After cultured and amplified, the morphology difference between transfected and non-transfected human amniotic epithelial cels was observed. The transfected human amniotic epithelial cells were observed under fluorescence microscope, and the cell cycle and the expression rate of EGFP in transfected human amniotic epithelial cells were detected by flow cytometry. RESULTS AND CONCLUSION:No obvious difference in the cell morphology was found between transfected human amniotic epithelial cells and normal human amniotic epithelial cells cultured in vitro. Flow cytometry analysis revealed that the EGFP positive rate was highest and reached up to 99.01% at 48 hours after transient transfection. The cell cycle of human amniotic epithelial cells transfected by the adenovirus vector was slowed a bit. To conclude, the adenovirus vector is a good medium of transfecting EGFP into human amniotic epithelial cells, and makes it more convenient to observe the further transformation of human amniotic epithelial celsin vitro.