PubMed · 14830669
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
E MATTHEWS. 1951-01-02. Facial prostheses.. https://pubmed.ncbi.nlm.nih.gov/14830669/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Explore the source record for details and available documents.
The side openings of a shade structure have a direct influence on where the shade is located and the level of scattered UV in the shaded area. UV exposures were assessed for the decrease in scattered UV beneath specific shade structures by the use of two types of side-on protection, namely, polycarbonate sheeting and evergreen vegetation. Dosimetric measurements conducted in the shade of a scale model shade structure during summer and winter showed significant decreases in exposure of up to 65% for summer and 57% for winter when comparing the use and non-use of polycarbonate sheeting. Measurements conducted in the shade of four shade structures with various amounts of vegetation covering different sides, showed that adequate amounts of and positioning of vegetation decreased the scattered UV in the shade by up to 87% for the larger solar zenith angles (SZA) of approximately 67 degrees and up to 30% for the smaller SZA of approximately 11 degrees when compared to the shade structure that had no surrounding vegetation.
AIM: Image-data-based navigation plays an important role during surgical treatment in anatomically complex areas. Conventional patient-to-image registration techniques on the basis of skin and bone markers require expensive and time-consuming logistic support. A new markerless, high-resolution laser surface scan technique for patient registration has been tested in experimental and clinical settings. METHODS: In a phantom study, a skull model was registered with laser scanning and marker-based algorithms. The registration procedure was repeated 25 times in each group. The values for the root mean-square error were calculated as a measure of the deviation of the forecast position from the actual position and the target difference. In a clinical setting, 21 consecutive patients who presented with cranio-maxillofacial disorders were scheduled for navigational surgery using laser surface scanning for patient-to-image registration. Here the accuracy was determined by anatomical landmark localization. RESULTS: In the experimental study, a root mean-square error of 1.3+/-0.14 mm, and a mean target deviation of 2.08+/-0.49 mm were found for laser scanning. In contrast, a root mean-square error of 0.38+/-0.01 mm and a mean target deviation of 0.99+/-0.15 mm were found for marker registration. The differences were statistically significant (p<0.005). A strong correlation between the root mean-square error and the target deviation was found for laser (r=0.96) and marker registration (r=0.95). During the 21 clinical procedures, the overall accuracy of laser scan registration determined by the root mean-square error was 1.21+/-0.34 mm, and the mean clinical precision was 1.8+/-0.5 mm. CONCLUSIONS: Three-dimensional laser surface registration offers an interesting approach for selected image-guided procedures in cranio-maxillofacial surgery.