Clinical results of a novel wide beam reconstruction method for shortening scan time of Tc-99m cardiac SPECT perfusion studies

A reconstruction method is presented for generation of three-dimensional maps of the grain boundaries within powders or polycrystals. The grains are assumed to have a mosaic spread below 1°. They are mapped by diffraction with a wide beam of hard X-rays, using a setup similar to that of parallel-beam absorption contrast tomography. First the diffraction spots are sorted with respect to grain of origin. Next, for each grain the reconstruction is performed by an algebraic algorithm known as three-dimensional ART. From simulations it is found that reconstructions with a spatial accuracy better than the pixel size of the detector can be obtained from as few as five diffraction spots. The results are superior to three-dimensional reconstructions based on the same data using a variant of the filtered back-projection algorithm. In comparison with layer-by-layer type reconstructions based on the two-dimensional ART algorithm, as introduced by Poulsen & Fu [J. Appl. Cryst.(2003),36, 1062–1068], the quality of the maps is found to be similar, provided that five to ten spots are available for analysis, while data acquisition with the three-dimensional method is much faster. The three-dimensional ART methodology is validated on experimental data. With state-of-the-art detectors, the spatial accuracy is estimated to be 5 µm.

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Development of a bioactive implant for repair and potential healing of cranial defects

Journal of Neurosurgery ◽

10.3171/2013.6.jns1360 ◽

2014 ◽

Vol 120 (1) ◽

pp. 273-277 ◽

Cited By ~ 33

Author(s):

Thomas Engstrand ◽

Lars Kihlström ◽

Erik Neovius ◽

Ann-Charlott Docherty Skogh ◽

T. Kalle Lundgren ◽

...

Keyword(s):

Bone Healing ◽

Bone Ingrowth ◽

Clinical Results ◽

Cranial Bone ◽

Reconstruction Method ◽

Ceramic Tiles ◽

Cranial Defect ◽

Cranial Implant ◽

Soft Tissue Covering

The repair of complex craniofacial bone defects is challenging and a successful result is dependent on the size of the defect, quality of the soft tissue covering the defect, and choice of reconstruction method. The objective of this study was to develop a bioactive cranial implant that could provide a permanent reconstructive solution to the patient by stimulating bone healing of the defect. In this paper the authors report on the feasibility and clinical results of using such a newly developed device for the repair of a large traumatic and therapy-resistant cranial bone defect. The patient had undergone numerous attempts at repair, in which established methods had been tried without success. A mosaic-designed device was manufactured and implanted, comprising interconnected ceramic tiles with a defined calcium phosphate composition. The clinical outcome 30 months after surgery revealed a restored cranial vault without postoperative complications. Computed tomography demonstrated signs of bone ingrowth. Examination with combined 18F-fluoride PET and CT provided further evidence of bone healing of the cranial defect.

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