Date  File  Comment by  Comment  Rating 

12 Jun 2014  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  mat  
29 May 2014  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Hamdi Mahdjoub  
28 May 2014  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Bella  Would it be possible to use this program to forward project a 3D image where dx=dy, but dx=dy!=dz? Right now, my parameters are: %% Parameter setting %% param.nx = 400;
%The real detector panel pixel density (number of pixels)
% Detector setting, according to Varian Trilogy OBI (real size)
% Xray source and detector setting
% This confusing stuff
but this doesn't create the correct forward projections, so far as I have been able to check. Am I trying to do something that is impossible in image processing? Thank you! 

24 May 2014  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Rama Teja A S  Please include analytical equation for better understanding. Or please explain the algorithm in projection.m. If possible please include analytical equation references 

11 Nov 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  Hi, Erick, That's a good point. This factor is used in the weighted backprojection for fanbeam and conebeam geometries.
Result is similar compared to the previous one, In real geometry, this factor is not critical factor for the image, because CT rotates 360 deg (average factor ~ 1) as well as itself is close to 1. However, I think I omitted it for fast calculation, soon I will fix it for accuracy. Thanks a lot. ps) you can directly send email to me, it is sometimes difficult to check comments here.


11 Nov 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  erick  Hi, I compared you work with the FDK equation in some papers, it seems that your FDK algorithm omited a factor. I added this factor in the "backprojection.m" of your algorithm, the code is shown as follows. Ratio=param.DSO.^2./(param.DSOry).^2;
Do you think it is necessary to add this factor? I am waiting for your reply, Thank you. 

28 Oct 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  Hi Erick, First Question: If you have real projections ("RealProj"), then first calculate: 1. I0 = max(RealProj(:)); % if you don't know I0
Here, "I0" is the blank image (intensity of source) as mentioned in the text book.
Solution of cases 1) step 3. Proj(isinf(Proj)) = 0; 2) step 1. Define I0 as a background (high intensity) average.
Then, you can execute FDK or MLEM as in Demo.m. Second Question: Parameter setting is very important. Image resolution is defined by detector size and distances of DSO, DSO. In your case, DSD is 700 and DSO is 560. so ratio is 560/700 = 0.8. Then detector size of a pixel is 50/1024, so maximum resolution of a voxel is 50/1024*0.8. Now, voxel resolution "dx=dy=dz" is defined. then define the number of voxels that covers whole images (nx, ny, nz).
Last Question:
Thanks, 

28 Oct 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  erick  Thank you for your answers. I have a few questions left.
Last question, would you please give some reference about FDK algorithm not using isocenter(DSO) domain. Thank you. 

27 Oct 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyungsang  Hi Erick, 1. w = cos(theta), to calculate w, my code considers distances in detectors, as your comment, many books calculate in isocenter (DSO) domain. In this case, uu and vv should be differently calculated by considering distance ratio from source to center and source to detector. Please think about angle between isocenter line and extension line sourcevoxeldetector. 2. In my code, pi/2 rotate shift is for calculating exactly your comment. "interp2" function results in 90 degree rotated image. So I did "angle" > "anglepi/2", and I think DSO+ry is right. 3. If you want to get as real projection data, first set blank scan intensity "b", this is related to "dose", then measurement M = b*exp(projection(obj)). Thanks your comment.


27 Oct 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  erick  I am wondering if I have real projected images, do I need to use the function "CTprojection"? 

27 Oct 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  erick  Good work. I have some questions.
Would you please give me some suggestion, thank you. 

04 Apr 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  Hi, Masoud Hashemi,


30 Mar 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Masoud Hashemi  I am wondering if the projection function is for Arc detectors (3rd Generation) or Flat detectors? 

02 Mar 2013  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Tai Chieh  Great! 

16 Dec 2012  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  ljpzgx  The codes can run but the result is not very good,can you upload the referrences you refer for the codes,so tha we can understand clearly. Thank you！ 

13 Mar 2012  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  This program is similar to other programs but
To accelerate speed,


12 Mar 2012  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  You can use "matlabpool", From for i=1:n (angle)
To parfor i=1:n (angle)
This increases the performance more than twice in quad cores. 

12 Mar 2012  3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes  Kyung Sang Kim  Please change the function code "projection_pixel.m": From dist = (SAD+SDD)./sqrt((SAD+SDD)^2 + uu.^2 + vv.^2)*abs(ys(2)ys(1)); To dist = sqrt((SAD+SDD)^2 + uu.^2 + vv.^2)./(SAD+SDD)*abs(ys(2)ys(1)); Thank you, :) 
