[vtkusers] Hounsfield Units of Human body part

[Scott Johnson]

Hello Chasan,

 

The VTK DICOM readers already take the Rescale Slope and Intercept
values into account.  The voxel values from DICOMReader are already in
HU so the offset should not be applied.

 

The definition of Rescale Slope and Rescale Intercept can be found in
the DICOM Standard Part 3:

*         Rescale Intercept             (0028,1052)

The value b in relationship between stored values (SV) and the output
units.  Output units = m*SV+b

*         Rescale Slope                    (0028,1053)

m in the equation specified in Rescale Intercept (0028,1052).

 

                                -- Scott

 

From: vtkusers-bounces at vtk.org [mailto:vtkusers-bounces at vtk.org] On
Behalf Of Chasan KIOUTSOUKMOUSTAFA
Sent: Thursday, August 26, 2010 8:17 AM
To: vtk mailList
Subject: [vtkusers] Hounsfield Units of Human body part

 

Hi all
 I'm trying to get iso surfaces of a human-body parts such as ( bone,
liver, muscle, skin) from DICOM datasets. For extraction of iso
surfaces, I'm using the MarchingCubes algorithm, and it needs the
Hounsfield Unit (HU) for extraction. I've found many different HU scales
for human body parts. My questions are;
1. In DICOM tags, there is a value called "RescaleIntercept" what
exactly it is ? 
is it an offset of CT dataset ? and if it is for example -1000, so what
is the real HU of water for -1000 value ?

HUofBone = (double)DicomReader->GetRescaleOffset() + 1200.0;
boneExtractor->SetInputConnection(Dicomreader->GetOutputPort());
boneExtractor->SetValue(0, HUofBone);

In the given code, what GetRescaleOffset returns ?  





Chasan KIOUTSOUKMOUSTAFA



Chasan KIOUTSOUKMOUSTAFA

 

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