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From: Stanley on 3 Apr 2010 15:10
Good morning,

I learning how to reconstruct SPECt images and need some help.

Here’s what I have:

A 128x64 array, 120 angles (slices), 2 byte integer

To open the projection file into a 2-D array I used the following commands:

fid=fopen(‘imageA.prj’);
B=fread(fid,[128,64], ‘uint16’);

theta = linspace(270, -90, 120) This gives me 120 different projection angles

theta will be used with iradon

#1 I want to reshape imageA so that I have a 3-D matrix (x, y, projection angle)

• I’ve tried the reshape command without success and really don’t know how to proceed

#2 I also want to create a sinogram from the projection data

• To reduce noise I was provided with the following code that sum to sum the 6 through 21 transaxial slices of the projection data:

sino_sum(1:ndim, 1:nang)=0.;
for k=1:nang
for i=1:ndim
for j=6:21
sino_sum(I,k)=sino_sum(I,k) +B(i, j, k)
end
end
end

Can you help me convert the projection data from a 2D array into a 3D array?
Can you show me how to make a sinogram? – do I use iradon?
I believe nang is the number of projection angles (i.e., 120)
I’m not sure about the value for ndim

Thank you in advance.

Stanley
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