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<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Hi Alejandro,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Practical answer:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The markers you have chosen may work for you, but we haven’t used spherical markers for this form of registration (see theoretical answer for reasoning).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Try the doughnut fiducials from IZI (<a href="http://www.izimed.com/catalog.shtml?&Vl=6&Tp=2">http://www.izimed.com/catalog.shtml?&Vl=6&Tp=2</a>) or the conical fiducials from Beekley (http://www.beekley.com/MultiModality/index.asp).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">We have used both and they worked well for us. You can request a sample from these companies and they will send you several markers. There’s nothing like trying it out for yourself.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Theoretical answer (fiducial choice in general):<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">What you want from a fiducial is that the SAME point be easily and accurately localized in the volume (CT/MR) AND in the physical world. This means that you need to think about the fiducial attachment
(implanted or skin adhesive), and shape (sphere, doughnut, conical).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Ideally you would use bone implanted fiducials, but skin adhesive fiducials are the most popular. The reason for this choice is that there is no additional trauma, but on the other hand they
will often fall off.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The fiducial you chose, spherical, is easily localized in the volume both manually or automatically. You get the center of the sphere. In the physical world to accurately digitize the center
of the sphere you need a tracked and calibrated tool that has a cup with a specific diameter that fits the sphere. I used this approach in the past with a customized tool for registration so it is doable. Usually you will have a pointer tool and not a cup
tool so your localization in the physical world will be less accurate. [The reason most labs have a pointer tool readily available is that most tracking systems provide such a tool when you buy the system].<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The conical and doughnut shaped fiducials may be less accurately localized in the image but this depends on your localization approach, manual or automatic. They are localized relatively accurately
in the physical world using a standard pointer tool, hence our choice to use these markers.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> Ziv<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">-- <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Ziv Yaniv, PhD.,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Principal Investigator,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">The Sheikh Zayed Institute for Pediatric Surgical Innovation<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Children's National Medical Center<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">6th Floor Main Hospital, Room M7740<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">111 Michigan Ave., N.W<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Washington, D.C 20010<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Phone: 202-476-1288<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">email: zyaniv@childrensnational.org<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">web: <a href="http://yanivresearch.info">
<span style="color:#1F497D;text-decoration:none">http://yanivresearch.info</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> igstk-users-bounces@public.kitware.com [mailto:igstk-users-bounces@public.kitware.com]
<b>On Behalf Of </b>Alejandro De León Cuevas<br>
<b>Sent:</b> Wednesday, October 16, 2013 9:03 PM<br>
<b>To:</b> igstk-developers-request@public.kitware.com; igstk-users@public.kitware.com<br>
<b>Subject:</b> [IGSTK-Users] Which kind of fiducials are best for image registration in IGSTK?<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN" style="font-family:"Times New Roman","serif"">Hi everybody, I have a question that I hope somebody there can answer. I want to know what kind of fiducials are best
for image registration, I will use it on an artificial skull and make the registration procedure using IGSTK with DICOM images (CT) of the skull. I found skin markers as shown in this link:</span><span style="font-family:"Times New Roman","serif""><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN" style="font-family:"Times New Roman","serif""> </span><span style="font-family:"Times New Roman","serif""><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN" style="font-family:"Times New Roman","serif""><a href="http://www.pdchealthcare.com/en-us/products/SDM-CT1.html">http://www.pdchealthcare.com/en-us/products/SDM-CT1.html</a></span><span style="font-family:"Times New Roman","serif""><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN" style="font-family:"Times New Roman","serif""> </span><span style="font-family:"Times New Roman","serif""><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN" style="font-family:"Times New Roman","serif"">but I don’t know if they are optimal. Thank you for your attention.</span><span style="font-family:"Times New Roman","serif""><o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Times New Roman","serif"">No virus found in this message.<br>
Checked by AVG - <a href="http://www.avg.com">www.avg.com</a><br>
Version: 2014.0.4158 / Virus Database: 3614/6755 - Release Date: 10/16/13<o:p></o:p></span></p>
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