Herbal extract loaded chitosan-based nanofibers as a potential wound-dressing

Semelil is an herbal-based compound which is used for the treatment of chronic wounds, especially diabetic foot ulcers. On the other hand, Electrospun nanofibers have many characteristics such as mimicking extracellular matrix structure, efficiency as bacterial barrier, appropriate water vapor transmission rate, and provision of adequate gaseous exchange which make them ideal candidates for wound-healing application. The aim of this study was to incorporate Semelil in electrospun nanofibers to benefit both the advantages of Semelil and electrospun nanofibers for the treatment of wounds. To this aim, the blend solution of chitosan, polyethylene oxide [PEO] and the herbal extract were electrospun and chitosan-based nanofibers loaded with the herbal extract were fabricated. The as-spun fibers were characterized by scanning electron microscopy [SEM], Fourier transform infrared spectroscopy [FTIR] and thermogravimetric analysis [TGA]. The swelling ratio and drug release behavior of the electrospun fibers were also studied. Uniform and bead-free nanofibrous mats loaded with 10-50 Wt. %extract were successfully fabricated. The FTIR spectrum indicated that the chemical nature of chitosan was not changed in the process of electrospinning. TGA analysis confirm both polymers and extract in electrospun mats. The extract loaded mats showed a high swelling ratio and a burst release of extract after 1h incubation in PBS. Mats with lower amount of drug exhibited graduate increase in the cumulative release of drug after initial burst release

Computed tomography based attenuation correction in PET/CT: principles, instrumentation, protocols, artifacts and future trends

The advent of dual-modality PET/CT imaging has revolutionized the practice of clinical oncology, cardiology and neurology by improving lesions localization and the possibility of accurate quantitative analysis. In addition, the use of CT images for CT-based attenuation correction [CTAC] allows to decrease the overall scanning time and to create a noise-free attenuation map [micro map]. The near simultaneous data acquisition in a fixed combination of a PET and a CT scanner in a hybrid PET/CT imaging system with a common patent table minimizes spatial and temporal mismatches between the modalities by elimination the need to move the patient in between exams. As PET/CT technology becomes more widely available, studies are beginning to appear in the literature that document the use of PET/CT in a variety of different cancers, including lung, thyroid, ovarian, lymphoma, and unknown primary cancers, and for general oncology, cardiology and neurology applications. Specific applications of PET/CT, such as those for radiation therapy planning, are also being explored. The purpose of this review paper is to introduce the principles of PET/CT imaging systems and describe the sources of error and artifact in CT-based attenuation correction algorithm. This paper also focuses on recent developments and future trends in hybrid imaging and their areas of application. It should be noted that due to limited space, the references contained herein are for illustrative purposes and are not inclusive; no implication that those chosen are better than others not mentioned is intended