<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">HUofAir = (double)(reader->GetPixelRepresentation() * reader->GetRescaleSlope()) + (double) reader->GetRescaleOffset();<br>// HuofAir represents -1000 HU<br>HUofBone = HUofAir + 2250.0; // 1250 HU for Bone<br>HUofMuscle = HUofAir + 1050.0; // 50 HU for Muscle<br>HUofFat = HUofAir + 880; // -120 HU for Fat<br><br>so, this code must calculate the exact HU value.. Am i right ?<br>I've four different types of DICOM datasets, two of them is nearly optimal, However other ones optimal bone value is about 200 HU..<br>is HU values is so dependent to patient ? what can be ?<br><br>Chasan KIOUTSOUKMOUSTAFA<br><br>--- On <b>Thu, 8/26/10, Scott Johnson <i><Scott.Johnson@neuwave.com></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Scott Johnson
<Scott.Johnson@neuwave.com><br>Subject: RE: [vtkusers] Hounsfield Units of Human body part<br>To: "Chasan KIOUTSOUKMOUSTAFA" <chasank@yahoo.com>, "vtk mailList" <vtkusers@vtk.org><br>Date: Thursday, August 26, 2010, 6:06 PM<br><br><div id="yiv554529855">
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<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">Hello Chasan,</span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">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.</span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">The definition of Rescale Slope and Rescale Intercept can be
found in the DICOM Standard Part 3:</span></p>
<p class="yiv554529855MsoListParagraph" style=""><span style="font-size: 11pt; font-family: Symbol; color: rgb(31, 73, 125);"><span style="">·<span style="font: 7pt "Times New Roman";">
</span></span></span><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">Rescale Intercept (0028,1052)</span></p>
<p class="yiv554529855MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: rgb(36, 64, 97);">The
value b in relationship between stored values (SV) and the output units. Output
units = m*SV+b</span></p>
<p class="yiv554529855MsoListParagraph" style=""><span style="font-size: 11pt; font-family: Symbol; color: rgb(31, 73, 125);"><span style="">·<span style="font: 7pt "Times New Roman";">
</span></span></span><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);">Rescale Slope (0028,1053)</span></p>
<p class="yiv554529855MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "sans-serif"; color: rgb(36, 64, 97);">m in
the equation specified in Rescale Intercept (0028,1052).</span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> --
Scott</span></p>
<p class="yiv554529855MsoNormal"><span style="font-size: 11pt; font-family: "sans-serif"; color: rgb(31, 73, 125);"> </span></p>
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<p class="yiv554529855MsoNormal"><b><span style="font-size: 10pt; font-family: "sans-serif";">From:</span></b><span style="font-size: 10pt; font-family: "sans-serif";"> vtkusers-bounces@vtk.org
[mailto:vtkusers-bounces@vtk.org] <b>On Behalf Of </b>Chasan KIOUTSOUKMOUSTAFA<br>
<b>Sent:</b> Thursday, August 26, 2010 8:17 AM<br>
<b>To:</b> vtk mailList<br>
<b>Subject:</b> [vtkusers] Hounsfield Units of Human body part</span></p>
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<p class="yiv554529855MsoNormal">Hi all<br>
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 <b>different</b> HU scales for human
body parts. My questions are;<br>
1. In DICOM tags, there is a value called "RescaleIntercept" what
exactly it is ? <br>
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 ?<br>
<br>
HUofBone = (double)DicomReader->GetRescaleOffset() + 1200.0;<br>
boneExtractor->SetInputConnection(Dicomreader->GetOutputPort());<br>
boneExtractor->SetValue(0, HUofBone);<br>
<br>
In the given code, what GetRescaleOffset returns ? <br>
<br>
<br>
<br>
<br>
<br>
Chasan KIOUTSOUKMOUSTAFA</p>
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<br>
Chasan KIOUTSOUKMOUSTAFA</p>
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