The screen-film system is replaced by computed radiography system for recording the images of the patients during X-ray radiography examinations. The change in imaging system requires the re-establishment of the institutional diagnostic reference levels (DRLs) for different types of X-ray examinations conducted at the hospital. For this purpose, patient specific parameters [age, height, weight, body mass index (BMI), object to image distance (OID)] and machine specific parameters (kVp, mAs, distance and field sizes) of 1875 patients during 21 different types of X-ray examinations were recorded for estimating the entrance skin dose (ESD). The ESD for each of these patients were estimated using measured X-ray beam output and the standard value of the back scatter factor. Five number summary was calculated for all the data for their presentation in the Box-Whisker plot, which provides the statistical distribution of the data. The data collected indicates that majorly performed examinations are cervical spine AP, Chest PA and Knee Lat with percentage contributions of 16.05, 16 and 8.27% respectively. The lowest contribution comes from Hip Lat which is about 1.01%. The ratio of measured ESD (maximum to minimum) for these examinations is found to be highest for the cervical spine AP with a value of 50 followed by Thoracic spine AP of 32.36. The ESD ratio for Chest PA, Knee Lat and Lumbar Spine AP are 30.75, 30.4 and 30.2 respectively. The lowest ESD ratio is for Hip Lat which is 2.68. The third quartile values of ESDs are established as the institutional DRLs. The ESD values obtained for 21 different X-ray projections are either comparable or lesser than the reported national/international values.
Fibroblasts and macrophages are the two major types of cells responding to implanted biomaterials. They play crucial roles in inflammatory responses, host-material interactions and tissue remodeling. However, the synergistic interactions of these two cell types with biomaterials are not fully understood. In this investigation, an in vitro fibroblast/macrophage co-culture system was utilized to examine the biocompatibility and the potential to induce inflammatory responses of an electrospun Dextran/PLGA scaffold. The scaffold did not affect the morphologies, attachments, proliferations and viabilities of both the fibroblasts and macrophages, cultured separately or together. Moreover, it only activated a small subset of the macrophages implicating a low potential to induce either severe acute or chronic inflammatory response. Additionally, fibroblasts played a role in prolonging macrophage activation in the presence of the scaffolds. Using antibody arrays, IL-10, SDF-1, MIP-1 gamma and RANTES were found to be up-regulated when the cells were incubated with the scaffolds. The results of subdermal implantation of the Dextran/PLGA scaffolds confirmed its biocompatibility and low inflammatory potential.
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