Acceptance tests scatter fraction

Acceptance tests are a battery of quality control tests performed to verify various parameters specified by the manufacturer for a PET scanner. These are essentially carried out soon after a PET scanner is installed in order to establish the compliance of specifications of the device. The most common and important specifications are transverse radial, transverse tangential, and axial resolutions sensitivity scatter fraction and count rate performance, ft is essential to have a standard for performing these tests so that a meaningful comparison of scanners from different manufacturers can be made. 

What are acceptance tests Describe the methods of determining sensitivity and scatter fraction for a PET scanner. 

Because the simplified solufion obfained by Kubelka is a two-constant equation and therefore experimentally testable, and because so many other workers derivations are derivable from Kubelka and Munk s work, their solution is the most widely accepted, tested and used. Other workers have derived solutions to the radiation transfer equation that are more complicated than these two-constant formulas. For example, a third constant has been added to account for different fractions of forward and back scattering [36]. Ryde [37,38] included four constants since a difference in the scattering between incident light and internally diffused light is assumed, while Duntley [39] developed a model with eight constants, as a difference between both the absorption and scattering coefficients due to incident and internally diffused radiation was assumed. However, none of these theories is readily applicable in practice, and therefore the treatment of Kubelka is most often applied. 

In the example given above it becomes apparent that only a subset of all AE could be detected and even be located with an acceptable accuracy. Results then represent the ongoing deterioration processes only at a fraction. Localization capability decreases with increasing damage of the test specimen, especially when cracking of the material occurs in some regions and elastic waves are scattered and reflected. 

---