Thesis

48 Part I Chapter 2 Table 3. Parameters from the three main multimodality camera manufacturers. Manufacturer General Electric Philips Siemens Reconstruction algorithm OSEM 3D OSEM 3D OSEM 3D Attenuation and scatter correction Yes Yes Yes Resolution recovery Evolution Astonish Flash 3D Parameters Iterations 3 Subsets 10 Butterworth filter (10/0.5) Iterations 3 Subsets 10 Hanning filter (threshold 1.73) Iterations 5 Subsets 8 Gaussian filter (4mm) 5. Adapting scan parameters The suggested imaging parameters may be adapted in consideration of the specific clinical condition of the patient (e.g. pain due to bone metastases, vertebral fractures, loosening prosthesis, etc). In such circumstances, shortening the duration of the examination by decreasing the time interval between injection and imaging, reducing acquisition time, or increasing the administered activity can be considered. 6. Selecting the appropriate image acquisition technique 1. Sequential planar acquisitions are used in the assessment of various diseases: infectious or inflammatory diseases, trauma, malignancy or pain syndromes affecting the extremities. 2. Whole body bone scintigraphy is routinely used in oncology and other settings. In those cases, limited bone scan or spot views are thus indicated only where a specific clinical problem detected on whole body image needs to be clarified. 3. Pinhole collimator acquisitions are preferentially reserved for studies in children, and in particular for scanning the hips (osteochondritis, aseptic necrosis). 4. Multimodality SPECT/CT imaging is indicated for the assessment of equivocal lesions on planar bone scintigraphy or localized pain syndromes with normal findings on planar scintigraphy, in particular in the staging of malignancies that have a tendency to metastasize to bone [54]. SPECT/CT can also be used in case of multiple equivocal benign lesions in the axial or appendicular skeleton, to increase specificity and diagnostic certainty.

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