Describe how to select imaging parameters to obtain PD-weighted images.

1. Explain what is PD-weighted contrast. Describe how to select imaging parameters to obtain PD-weighted images. Explain why a large TE cannot be used

2. Suppose we are imaging a human brain (see Table 12.2 for the NMR properties of different brain tissues). We use the strategy described above in Problem 12.6 and acquire signals after the system is in the steady state. For simplicity, we assume the intensity of the reconstructed MR image is directly proportional to the magnitude of the transverse magnetic field right after the RF excitations. In order to get maximal signal strength, we use π/2 pulses.

(a) In order to get the best contrast between GM and CSF, what is the best value for TR?

(b) Using the TR value computed in part (a), what is the contrast between GM and CSF? What is the contrast between GM and WM?

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….