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Question problem reading DICOM files 

Forum: Medical Applications
Date: 10 Jul, 2013
From: George Dedes <George Dedes>

Hi,

I am using the DICOM example to read several different DICOM files. Apart from the examples included with the code and another CT that I tried, all other DICOM CT images I tried to read seem to have some problem with the DicomHandler.

For some reason it seems that the info is not read correctly (reading wrong, or at wrong positions from the binary?) and several errors occur. For example, when it creates the g4dcm files, the first few material lines that come directly from Data.dat are of course ok, but later on there is some wrong info. Usually it starts by reading wrong coordinates/image size.

So, while it finds the rows and columns correct and the X dimension also correct, Y and Z dimension are wrong (even 0) and sometimes densities are also negative ( "@@@ Error density = -1 ..."). I have checked those images with external viewers and they are definitely OK. Looking a bit at the DicomHandler itself in the case of 0 Y dimension:

343 fPixelSpacingX = atof( datas.substr(0,iss).c_str() );

344 fPixelSpacingY = atof( datas.substr(iss+2,datas.length()).c_str() );

fPixelSpacingX is ok while datas.substr(iss+2,datas.length()).c_str() is an empty string and fPixelSpacingY is 0. And I suspect that similar problems occur later on in the process. Then the image is a single line in the XY plane, unless I edit Y myself in the g4dcm file and it is able to create a 3D geometry (although is has some negative densities).

I would be grateful if someone can help me with what is going on with the binary (dcm) reading, as it is not really my strong point in C++.

I can also send the corresponding dcm files so that the same problems could be reproduced.

Thanks in advance,

George

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1 None: Re: problem reading DICOM files   (Pedro Arce - 10 Jul, 2013)
(_ More: Re: problem reading DICOM files   (George Dedes - 10 Jul, 2013)
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