Physics and Radiobiology of Nuclear Medicine

postacquisition reformatting. Although the list mode acquisition provides wide flexibility, its major disadvantages are larger m ...

Gated Study The gated study was introduced in the mid-1970s to determine the ejection fraction of the heart by acquiring two ima ...

puted tomography (CT) or magnetic resonance imaging (MRI) anatomical images of an organ are superimposed onto the corresponding ...

image data in a movie or cinematographic (cine) mode, whereby a rotating 3-D image is seen on the monitor screen. This type of p ...

munications in Medicine (DICOM), which all vendors are recommended to adopt for compatibility among different software. Some of ...

patient on his/her computer from other locations within the PACS, rather than waiting for the hardcopy from the imaging departme ...

tries connecting through PACS’ different healthcare institutions for ex- change of patient care information. By virtue of telera ...

12 Single Photon Emission Computed Tomography 153 Tomographic Imaging Conventional gamma cameras provide two-dimensional planar ...

154 12. Single Photon Emission Computed Tomography Fig. 12.1. Four slices of the heart in the short axis. Fig. 12.2. A dual-head ...

The detector head rotates around the long axis of the patient at small angle increments (3° to 10°) for collection of data over ...

in the anterior and posterior positions. This causes loss of data and hence loss of spatial resolution in these projections. To ...

is called simple backprojection. When many projections are backprojected, a final image is produced as shown in Figure 12.3C. Ba ...

similarly backprojected into the reconstruction matrix. This type of back- projection results in superimposition of data in each ...

Filtered Backprojection The simple backprojection has the problem of “star pattern” artifacts (Fig. 12.3C) caused by “shining th ...

ilarly, all pixels in the acquisition matrix are smoothed, and the profiles are then backprojected. The spatial kernel described ...

of a series of sinusoidal waves of different amplitudes, spatial frequencies, and phase shifts running across the image (Fig. 12 ...

The Fourier method of reconstruction can be applied in two ways: either directly or by using filters. In the direct Fourier meth ...

representing an image projection. Because the acquisition data are discrete, the maximum number of peaks possible in a projectio ...

eliminated is called the cut-off frequency (c). As the cut-off frequency is increased, spatial resolution improves and more ima ...

cut-off value should be chosen so that primarily noise is removed, and image detail is preserved. Note that the Nyquist frequenc ...