Explain the reasoning behind Eq. (7.20) for normal anisotropy, and Eq. (7.21) for planar

1.Explain the reasoning behind Eq. (7.20) for normal anisotropy, and Eq. (7.21) for planar

 

anisotropy, respectively. Equation (7.20) on p. 391 represents an average

R value by virtue of the fact that all directions (at 45circ intervals) are taken into account.

2. Describe why earing occurs. How would you avoid it? Would ears serve any useful purposes?

Explain. Earing, described in Section 7.6.1 on p. 394, is due to the planar anisotropy of the sheet metal. Consider a round blank and a round die cavity; if there is planar anisotropy, then the blank will have less resistance to deformation in some directions compared to others, and will thin more in directions of greater resistance, thus developing ears.

find the cost of your paper

Explain why attenuation is not a big problem in PET.

Consider a 2-D object consisting of two triangle compartments, as shown in Figure P9.4. Suppose a solution containing a 511 KeV gamma ray emitting radionuclide with concentration f = 0.5….

Give the mean and the variance of the reconstructed image, mean[ˆ f(x, y)] and var[ˆ f(x, y)].

Ignoring the inverse square law and attenuation, an approximate reconstruction for SPECT imaging is given by where c˜() =  {||W()} and W() is a rectangular windowing filter that cuts off at = 0…..

Find the numerical responses in each to an event in crystal C(4, 6).

Suppose a PET detector comprises four square PMTs (arranged as a 2 by 2 matrix) and a single BGO crystal with slits made in such a way that it is….