X-Ray Lab & Imaging

CurrentsQuarterly Publication of the American Association of Dental Maxillofacial Radiographic Technicians Fall 2006

Inside This Issue3-D Models Dr. Lucia Cevidanes...........1

President's Message Jeannie Herriott........2

Editor’s View Camille Mayorga...............5

News and Trends .........................................6

California Report Matt Kroona................10

Newsletter Helper Andi Andersen..............11

Committee Report Merry Hampton .........13

Conference Highlights ...........................14

New Product RLMS Bill Bradley .........28

Lab Products ............................................30

Superimposition of 3-Dimensional Cone-Beam Computed-Tomography Models

By: Lucia H. S. Cevidanes, Alexandre Motta, Martin A.Styner, and William R. Proffit

This paper contains recent updates of our work on 3Dsuperimposition and our publication in the American Jour-nal of Orthodontics and Dentofacial Orthopedics,129(5):611-8. Three-dimensional (3D) imaging techniquesand tools now also includes analysis of soft tissue structuresand computer simulation of surgical procedures. 3D imageanalysis can provide valuable information to clinicians andresearchers.But as we move from traditional 2-dimensional(2D) cephalometric analysis to new 3D techniques, it is oftennecessary to compare 2D with 3D data. Cone-beam com-puted tomography (CBCT) provides simulation tools that canhelp bridge the gap between image types. CBCT acquisi-tions can be made to simulate panoramic, lateral, and poster-oanterior cephalometric radioagraphs so that they can be com-pared with preexisting cephalometric databases. Applicationsof 3D imaging in orthodontics include initial diagnosis andsuperimpositions for assessing growth, treatment changes, andstability. Three-dimensional CBCT images show dental rootinclination and torque, impacted and supernumerary toothpositions, thickness and morphology of bone at sites of mini-implants for anchorage, and osteotomy sites in surgical plan-ning. Findings such as resorption, hyperplasic growth, dis-placement, shape anomalies of mandibular condyles, and mor-phological differences between the right and left sides em-phasize the diagnostic value of computed tomography acqui-sitions. Furthermore, relationships of soft tissues and the air-way can be assessed in 3 dimensions.

3D Continued on page 20

Dr. Lucia CevidanesUNC Dep. of OrthodonticsUNC School of Dentistry

Chapel Hill, NC

President's Message

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I was trying to think about something really newsworthy and maybe a little motivat-ing to write about for my last article in the AADMRT Currents, but I was clueless.After all, I’ve had three opportunities to contribute my thoughts and observationsto you throughout the year, and I was thinking that maybe I’ve said all I can say onthe subject matter. I’m still trying to absorb all the information I was given at therecent Monterey convention!

For those of you who attended the convention, I feel certain that not only did youfeel inspired by what the speakers had to say, but also you felt a certain camarade-rie with your peers, as every-one is so friendly and will-

ing to sharing their experiences. I usually comeback from these classes with my head buzzing withideas and a feeling of being recharged, andMonterey was no exception.

I liked the fact that all the speakers were very easyto talk to if we wanted – they seemed happy toaddress our concerns and problems. They lis-tened and appeared to value our comments andexperiences although that’s not surprising, as wedo have some very sharp members. The vendorswere not only informative, but also they were funto talk to and I came away with somewhat of awish list. I’m sure I’m not alone on that!

Most of all, however, I enjoyed the company ofevery member in our association. I love seeingthe same faces every year and look forward tomeeting new ones. When I’m in the company ofpeople that understand my work language, I ammotivated to do better in all aspects of my life,but especially when working with the public whoplace their trust in my knowledge and compas-sion.

Presidents Message continued on page 5

Jeannie Herriott

"When I’m in the company of peoplethat understand my work language, Iam motivated to do better in all aspectsof my life"

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Editor's View

The last newsletter included 2 new features. Matt Kroona sent in the first "CaseStudy" about a patient that came in to his lab to rule out a fractured jaw. The patient’sdentist initially asked for a standard panoramic, but when that did not reveal any-thing unusual an I-cat 3 dimensional scan was taken. The scan clearly showed a leftmandible fracture. Matt included pictures of the panoramic, axial and cross sec-tional slices from the i-CAT cone beam volume scan, and a 3 D rendering thatshowed the fracture well. I would like to have a new "Case Study" added as one ofthe regular features of every issue of the newsletter. All of us come across interest-ing cases and I would like for you to send yours to: editor@aadmrt.com and wewill feature it in the newsletter. Don’t be shy! Also a new item in the last newsletter was "Spotlight Tech". Craig Dial was kind enough to be the first technicianto share some of his personal history with all of us. I believe we all enjoyed reading about Craig and how he gotinto the business. We are not looking for the most technical lab or long-time technician; each and every one of ushas a unique situation that we would all like to read about. I would also like to include a Spotlight Student, soplease let us know about your special story and how you got into dental imaging as a profession. I want to take this opportunity to thank all the members who always help with the newsletter and are alwayswilling to give me a write-up on a topic when needed. The same members can always be counted on. Please joinin on the fun and enter your special Case Study or Spotlight Tech. Check out the photo collage on page 14 of thisnewsletter, Craig added a secret picture, can you find it? I look forward to receiving many e-mails!

Camille MayorgaMonterey, California

Presidents message continued from page 2

One of the first things I did when arriving back to the office was to read my Mission Statement that’s on the wallbehind the front desk, and to reaffirm my dedication to providing extraordinary service with care and kindness. You,

as members, have reminded me to do that and I thankyou.

Our association continues to provide excellent ongo-ing education and I urge you to attend our conventions,get to know your peers, read our informative newslet-ter, and know that we are all in this exciting professiontogether. I can’t wait to see what new technological

changes await us, because with the help and expertise of our association, I feel confident that we’ll be able to incorpo-rate the necessary changes as needed. What a great feeling that is! And that’s what I’m talking about!

"Our association continues to pro-vide excellent ongoing education andI urge you to attend our conventions"

News and Trends

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Sullivan-Schein and Imaging Sciences i-CAT™

Imaging Sciences International, Inc. has chosen Sullivan-Schein, the largest provider of healthcare products andservices to office-based practitioners, to be the exclusive distributor in the U.S. and Canada of the i-CAT Cone Beam3-D dental imaging system. Imaging Sciences’ sales and management teams are committed to working closely with Sullivan-Schein representa-tives to educate them on the technology and benefits of the i-CAT, and will continue to oversee and be involved in allaspects of customer service, training, and development. Thanks to the continued support and enthusiasm from i-CAT customers, Imaging Sciences has been able to take theirCone Beam 3-D imaging technology from the concept stage into market leadership. Now, joining forces with Sullivan-Schein, Imaging Sciences is dedicated to bringing Cone Beam 3-D imaging to dentists across the county and elevatingthe i-CAT into mainstream distribution. For more information on Imaging Sciences and the i-CAT please visit www.i-cat.com

School Passes Students

The first three students passed their boards andwere licensed by the state of California using theAADMRT program in July of 2006. All three werefrom C Dental X-Ray, and their names are:

Danniell CarigDarlene MarshMaria Romig

Congratulations to these three x-ray technicians,and we look forward to many more students fin-ishing and graduating into our field of dental radi-ography. Thank all of you whom helped this pro-gram become a reality.

Future Radiology Meetings

ACOMR- Asian Congress of Oral and MaxillofacialRadiology Venue: Bangalore, India December 2006 email:rvde@vsnl.com

AADMRT- American Association Of Dental RadiographicTechnicians 1-Day spring meeting in Oakland California onApril 28th www.AADMRT.com

IADMFR- International Congress of DentoMaxilloFacialRadiology in Beijing , China , on June 26-30, 2007.www.iadmfr.org

AAOMR- American Academy of Oral and MaxillofacialRadiology November 27 - December 1, 2007Chicago, Illinois www.aaomr.org

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Sirona Cone Beam CT

Sirona is working on a cone beam CT unit. No information as ofnow for the formal release date. But we do know that it will be a20 second scan, that the overhead rotates 220 degrees andtakes 200 frames after the first 20 degree of rotation. The vol-ume is 15 cm x 15 cm x 15cm, it will use aImage intensifier with a voxelsize: 0,3 and 0,15 mm³. Re-construction time may be 1,5 and 7 minutes dependingon the protocol, and it willhave a 85 kV / 5-7 mA ca-pability.

AADMRT Re-Print

Dolphin Imaging and Management Solutions askedthe AADMRT editor if they could republish ourfeatures article from the summer issue, and it wasre-published in the latest Dolphin September is-sue. The AADMRT editors granted permission aslong as our organization was recognized. Dolphinobliged by listing our group at the end of the articleand also included our web site.

Member Writes Article for Publication

Our member, Eric Iwamoto wrote an informative article for thelatest Dolphin newsletter on digital cameras advice. He explainshow to get consistent results with his camera by optimizing theimages by controlling lighting conditions, choosing the correctlens, hardware, and using proper settings.

If you, or an AADMRT member you know has published anarticle, please e-mail the editor so we can publish the informa-tion here. editor@AADMRT.com

X-Ray Lab For Sale

We have an opportunity for you!We will work withyou as an associate so you can puchase our x-rayfacility that has a thirty-three year history of profit-ability. Owning a lab will make it possible for youto earn what you are worth. For more informationcontact Ed Ginn by email: aginnjr@sbcglobal.netAct now!

News and Trends

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California Report

Submitted By: Matt Kroona

The Radiologic Technology Certification Committee of California (RTCC) met inSacramento on Thursday, September 21, 2006. The meeting was very warm andcordial, primarily because of the recent passage of SB 1670, which providedthat Limited Permit X-ray Technicians may perform digital radiography aftercompletion of 20 or more hours of instruction in digital technology. This sub-ject has been the center of discussion at RTCC meetings for many years and it’s

resolution is a welcome relief. SB 1670 does not apply to the dental laboratory permit which is alreadypermitted by law to perform digital radiographic procedures. Another subject of interest was the announcement that laboratories showing competence in accessingTitle 17 on the Internet will be deemed in compliance with the requirement to have a current copy available.To find Title 17 on the Internet, go to: http://ccr.oal.ca.gov “Search for a Specific Regulatory Section”

Title “17”Section “30100”“Search” The specific section of Title 17 that pertains to us is: · Division 1. Department of Health Services· Chapter 5. Sanitation· Subchapter 4. Radiation This is a fairly complicated process so take some time to familiarize yourself with it BEFORE you getinspected. Another action that affected us was the establishment of a subcommittee to review the “Minimum Stan-dards” for the Limited Permit in Dental Laboratory. This committee will be chaired by Matt Kroona andwill include Dawn Harrat, Dr. Bernie Goler (a medical radiologist member of the RTCC), an RHB staffmember, and others to be included at the discretion of the above members. Our hope is to review andupdate the education requirements for our permit and possibly draft a new state test. Stay tuned for moreinformation on this exciting process. The next RTCC meeting will be held in Southern California in early 2007.

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From Our Office To Your Door

Have you ever wondered who the muscle is behindthe AADMRT newsletter assembly and distribution?Meet Andi! Andi, a DDI Sacramento volunteer, workshard to ensure that your AADMRT quarterly news-letter gets stamped, addressed, and in your mailboxin a prompt and proficient manner! From the print-ers to your mailbox, Andi gets the job done. Becausethe assembly and distribution of the AADMRT news-letter is a very time consuming process, Craig &Camille would like to thank Andi for all of her hard

work and assistance in the process. Just as we strive toprovide the best customer service and care in our of-fices, Andi strives to provide you with her best by get-

ting the newsletter to you. Without her help, your newsletter may be delayed. Thanks Andi for beingsuch a great help to Craig, Camille and all of the hardworking AADMRT members who look to thenewsletter for the latest news and advancements in our field!

Andi (13 years old) comes into DDI and helps withthe AADMRT newsletter

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Committee Report

Submitted By: Merry Hampton, Executive Secretary

The AADMRT general membership meeting was held in Monterey Californiaat our annual conference on October 20th, 2006.

A Special “Thank you “to Bart Webb for hosting the lovely convention this year.

· Nominating Committee: Submitted by Sara Tarazi-3 new board members, Dan Halpert, DawnHarrat and Helen Tran.

· Membership: Submitted by Kathleen Cox-200 paid members, 70 unpaid from website file, 5 re-tired members. 32 E-mail international contacts, 13 became members. 126 Paying labs/Offices. 5Countries including the USA. Membership fee’s $75.00 for 2007 due no later than 12-31-2006 East-ern Standard Time (Paypal related). Charges change to $90.00 January 1st. 2007.

· Treasury: A change from Claudette Buehler to Devery Wallace has taken place over the last fewmonths.

· School: Matt Kroona reporting-17 active students and 4 inactive students. 8 students have gradu-ated and believe to have passed. School Assistance is Devery Wallace and Dawn Harrat. School Librar-ian is Tracey Saucier. Dawn is working on adding or adapting the experiments in 800R for facilities thatdo digital radiography. Matt Expects that Unit 10 (Computers and Image Formation) will be completedby October 15, 2006. Matt and Dawn are on a sub-committee that will evaluate the existing standardsagainst current technology and standard of care in our field.

· 2007 Spring Seminar: April 28, 2007-Seminar to be held in Oakland at the Hilton. Chaired byMerry Hampton

· 2007 Fall Convention: October 11-13th San Antonio Texas, Convention Chair is Lisa Franks.

Devery Wallace endeared us with the remembrance of Angie Saviez. Angie was a wonderful person andx-ray technician that has since past. Angie hosted our last convention that was held in Monterey manyyears ago. Angie touched many hearts within our organization. She has been greatly missed but alwaysremembered.

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Monterey Highlights

The 2006 fall conference held this year in beautiful Monterey and organized by Bart Webb was a great success. Barts’hard work, dedication to the AADMRT, and attention to detail is greatly appreciated by all members whom attended.

This meeting had many different subjects and speakers to listen to including some of our own members, Phil Abel andMerry Hampton, were also speakers this year, and they both did a great job with their presentations. We alwaysreceive a lot of value when our peers get up and speak on a subject they know well. We encourage more of you topresent on a subject in our ever-changing field. If this interests you, please contact the next seminar chair, or e-mail anyboard member. These conferences are a success because some key people have put effort into making them so.

Besides the informative and entertaining speakers, we also had a wonderful group of exhibitors. Theses people arewarm and welcoming, and they support us year after year, without them, our meeting would not be of success. We needto understand that these exhibitors have a choice as to what meetings their company chooses to attend. I hope each andevery one of you had a opportunity to visit and talk to each vendor this year. You do not want to miss out on any newproducts or services that they may be offering. If we want these exhibitors to continue to return, please make sure yougreet them and make them feel welcome.

Below are some highlights of the weekend events; the next few pages contain a short summary of each speaker’spresentation. Monterey Continued on page 16

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Dr. Paul BrownSubmitted by: Donna Eggers Dr. Brown showed us the value of using very high resolution 3Dscaning for research as well as use in dentistry. This virual 3D data can be shared anywhere inthe world. Many of our dental schools are using 3D data sets. This is the future and we can’tescape it.

Mr. Phil Abel

Dr. Cate Quas

Dr. Dov Almog

Ms. Cassandra GozinCassandra GozinSubmited by: Camille Mayorga Ms. Gozin spoke to us about the company Materialize. Materi-alize is a interactive implant software program. There are 2 different Packages available, SimplantPlanner for the dentists, and Simplant Master for Ct Sites or labs. The software can show the bonequality with hounsfield units, other features include collision detection, and mylohyoid undercut to afew. There is also a free viewing software available for guided drilling.

Phil AbelSubmitted by:Marcelle Jones Phil gave a presentation on dental digital photograpy. He reviewedthe history of dental photography giving credit to Mr. Cliff Freehe who, in the 1960’s, set the tech-niques and standards that we still use today. Our goal is still to document and study growth anddevelopment of the face and teeth. Phil recommended that a 60mm lens is not only satisfactory butbetter than the 105mm lens. It is easier to use because you are closer to the patient and there is nota significant difference in distortion from the 105mm. His camera recommendation was for theRebel XT with a battery grip. He also gave us some good websites to visit such as: www.americanboardortho.com - for board standards for photos and www.dpreview.com – and a websitefor camera information www.orthotechnology.com .

Monterey Highlights

Dr. Paul Brown

Dr. Cate QuazSubmitted by:Eric Iwamoto Cephalometric tracing analysis can be a very difficult task due to superimposi-tion, anatomical interference, and magnification of the image. Dr. Quas gave a concise presentation onlocating the most challenging points such as: Nasion (look for the V-notch and be mindful of the soft eyelidtissue), Supraorbitale, Odontoidale, Basion, Pterygoid Point, Gonion, Gnathion and several others. Dr. Quasextensively uses the tracing module in Dolphin Imaging to assist her to enhance the images to accuratelylocate the points of interest. By toggling between, radiograph, MIPS, emboss and other filters, Dr. Quasdemonstrated how to accurately pinpoint the various landmarks. Reviewing the buccal intraoral photographsand panoramic image also can be utilized to help identify landmarks. If the structure is obscured, look foradjacent structures for reference. Another fact to remember is that many Points, such as “A” Point andGnathion may differ simply based on whether it is a Downs, Bjork, or Jacobson defined landmark.

Dr. Dov AlmogSubmitted by:Camille Mayorga Dr. Almog spoke to our group about the need for CT scans for bestimplant placement and predictable aesthetic outcomes. He also informed us how the carotid arterycan be seen on a panoramic and early detection can help prevent strokes in high risk patients. Heshowed us the landmarks and how to see the carotid calcification. Dr. Almog is a wealth of knowl-edge and the AADMRT can always count on him to give a lively and informative talk.

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Merry HamptonSubmitted by: Kim Jamison Questions, comments and jokes…Merry Hampton’s “Round Table”covered all of the bases. The daily occurrences and challenges we face in our X-ray labs werepresented and discussed. Tips from the trades’ most seasoned veterans and suggestions for thosejust getting into the ‘biz’ were covered in this lively conversation. The talk concluded with Merrydelivering a special message via a personal tribute of what she strives to incorporate in and outsideof the work environment, “Passion.”

Arun SinghSubmitted by: Gail Finnigan Arun spoke about the “Magic Math” of Cone Beam Imaging. Hedescribed the technicalities of how the beam is projected on to the sensor at many angles and howthe voxels record the image, he also explained described why the field of view is cylindrical.Arun talked about how the software reconstructs volume in matrix axial views and can renderendless views from the volume data.

Amos NadlerSubmitted by: Camille Mayorga Mr. Nadler spoke on marketing techniques using exercises todetermine your specific companies goals. He stressed that if you align your marketing campaignwith your values, that your confidence will show and impress your target market. He ended hislecture with the quote: "You have one chance, One Life."

Chester WangSubmitted by: Pat Davis As of Oct 2006 there are about 8 CT scanning systems. There are 5types of 3D camera systems and about 5 types of software for this. Chester talked about theadvantage of using facial markers when using the ICAT. This is useful for both soft and hard tissuewhen applying to orthodontics. Chester showed us some of the latest techniques from DolphinImaging for processing, delivering, and integrating patient cases. The need for quick delivery and theability to put different images together in one location and email access is very important.

Mr. Amos Nadler

Mr. Arun Singh

Mr. Chester Wang

Mrs. Merry Hampton

Photos taken by: Phil Abel

Travis Engelman

Submitted by: Duane Perry Representing Align Technology and its product Invisalign, Travisspoke about the finer points of Invisalign and the future alignment with CBCT machines’ output toproduce a better diagnosis and aligners — not yet available but is in the works. All necessary datarequired by the company from the dentist can be burned to a CD in JPEG and sent to them.

Monterey Highlights

Mr. Travis Engelman

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Simplant™ File Conversion Services for CBCT

Highest quality reconstructions of dicom data into Simplant™ format come with a 100% money backguarantee on the first order. Conversions are $100 per arch for a basic conversion and cleanup ofartifacts present and $150 per arch for conversion and custom colorizing of vital anatomy. Phone617-820-5279 or visit: www.3ddx.com

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3D Continued from Page 1

To routinely benefit from 3-dimensional (3D) imaging, which can provide stacks of axial, lateral, and anteroposteriorslices, clinicians need user-friendly tools to construct virtual 3D models.

These can be used in initial diagnosis and assessing changes as a result of treatment. Although shape analysis toolshave become more readily available, most current software requires some computer expertise. As new tools aredeveloped, we can navigate away from the limitations of conventional cephalometrics, but we still need to allowcomparisons to previously acquired cephalograms.1 It is important to be able to use superimpositions and currentimages to evaluate growth changes. Various techniques for the reconstruction of 3D computed tomography (CT)images have been used in diagnosis, treatment planning, and simulation. 2-11 However, image superimposition for theassessment of changes with treatment poses many challenges. These challenges refer to registration and homologyissues and also to the difficulty of landmark locations on anatomic surfaces.12-16 Three-dimensional landmarkidentification requires suitable operational definitions of the landmark location in each of the 3 planes of space. Wedescribe superimposition methods that do not depend on landmarks or planes but, rather, compare the cranial basestructures voxel by voxel of each CT acquisition. These procedures allow us to calculate the rotation and translationparameters between 2 time-point images, display the superimposed 3D virtual models, and measure the distancesbetween the 3D model’s surfaces.

CONE-BEAM CT DEVICES

NewTom 3G (Aperio Services, Sarasota, Fla), ICAT (Imaging Sciences International, Hatfield, Pa), and HITACHI(CB MercuRay Hitachi Medical Corporation, Tokyo, Japan) are some of the the cone-beam (CB) CT (CBCT)scanners currently available with full-face fields of view for craniomaxillofacial applications. Image acquisition withthese CBCT scanners differs in patient positioning, time to complete the scan, resolution,and radiation doses. Whenassessing differences in effective radiation doses for different scanners, we also need to consider the radiation dose tothe salivary glands.17We have used NewTom 3G images for reformatting the voxels for isotropic of 0.5 x 0.5 x 0.5mm. Higherspatial resolution with smaller slice thickness increases image file size and requires greater computationalpowerand more user interaction time. Each scanner software allows reformatting of the original stack of axial imagesto simulate 2-dimensional (2D) panoramic x-rays, and lateral and anteroposterior cephalograms. Current researchtopics include comparisons of CBCT and conventional cephalograms. The CBCT cephalogram needs to simulate theperspective and magnification of conventional x-rays to allow comparisons to the populational norms available forour preexisting cephalometrics database (Figs 1 and 2).

Fig 1. Dolphin 3D beta version images (Dolphin Imaging and Management, Chatsworth, Calif). A, Lateral view of 3D virtual modelswith transparency of soft tissue. B, 2D cephalogram generated from 3D models with 0 magnification and in orthogonal projection. C,2D maximum intensity projection cephalogram. Dolphin 3D interface is user-friendly tool, allowing easy segmentation of anatomicstructures, 3D linear measurements, and option of orthogonal or perspective projections to simulate conventional cephalograms.

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FROM 2D SLICES TO 3D VIRTUAL MODELS

A key feature of CBCT images is the ability to navigatethrough the volumetric data set in any orthogonal slice win-dow18 (axial, lateral, and anteroposterior views; Fig 2).Instead of just analyzing 2D crosssectional images from a3D patient, clinicians must think in 3D directions instead of2D directions. From a set of more than 300 axial cross-sectional slices, it is possible to build 3D virtual models. Thefirst step in image processing is to convert scanned imagesfrom DICOM to a format that allows the segmentation ofanatomic structures. Image segmentation refers to the pro-cess of outlining the shape of structures visible in the cross-sections of a volumetric data set. After the segmentation, a3D graphic rendering of the volumetric object allows navi-gation between voxels in the volumetric image and the 3Dgraphics with zooming, rotating, and panning (Figs 3 and 4). The National Institutes of Health has web pages to aidresearchers in finding available image processing software.19 The image analysis tools we have used at the University ofNorth Carolina Orthodontic Department for 3D superimpositions are open-source, freely available software systems.

3D Continued on page 23

Fig 2. Axial, lateral (sagittal), and anteroposterior (coronal) cross-sections for each CT image acquisition. Using InsightSNAP, we canscroll through 330 axial, 360 lateral, and 360 anteroposterior slices ofvolumetric data. NewTom 3G software also allows panoramic views

Fig 3. 3D virtual models of 2 patients with hemifacial microsomia,showing segmentation of all slices stacked together without smooth-ing. A, Images acquired with 12-in field of view. Notecostocondral graft establishing working condyle. B, Images acquiredwith 9-in field of view. Note significant asymmetry and missingarticular fossa but presence of ramus and condyle on affectedside. (Resolution is compromised by patient motion during acquisi-tion; patient must remain still for 30 seconds after final alignment, andeven swallowing can cause noise.)

Fig 4. Transparency of bones allows visualization of developingpermanent teeth. Panoramic x-ray suggested that surgical pins fromgraft might be impairing tooth eruption, but CBCT 3D modelsshow that surgeon avoided tooth buds.

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3D continued from page 21CBCT APPLICATIONS

Three-dimensional CBCT images provide additional diagnostic informa-tion on (1) size, shape, and position of mandibular condyle heads; (2)width of the tooth-bearing portion; (3) morphology, inclination, displace-ment, or deviation of the lateral and medial surfaces of the mandibular ramiand body; (4) dental root positioning; (5) localization of impacted or su-per- numerary teeth; (6) palatal morphology; and (7) morphology of sitesfor placing implants or osteotomies This information can help in identifica-tion of affected structures, treatment planning, and future comparisons withlong-term follow-up of treatment stability (Figs 5 and 6).The identificationof the soft-tissue profile allows assessment of hard- and soft-tissue rela-tionships. However, CBCT does not assess muscular morphology, andmagnetic resonance imaging allows still more accurate renderings of thesoft tissues.5,8,21 Caution is necessary in assessing the airway withNewTom 3G images versus the iCat, because the morphology of the air-way space appears altered when the patient lies down for the NewTomacquisition (Fig 3). An interesting capability of 3D models is to allow su-perimposition along the whole surface of the cranial base for adults or inthe anterior cranial fossae for growing children. Although historically for2D super- imposition, we have used landmarks, planes, or 2D projectionsof surfaces, now software tools optimally align 3D CBCT data sets atdifferent time points with subvoxel accuracy after identification of thecranialbase structures (Fig 7). The computed registration is then applied tothe segmented structures to measure changes with time or treatment pro-cedures.

3D Continued on Page 24 Fig 6. Superior views of 3D models of mandibularrami of 3 patients with condylar shape anomalies.A, Patient with idiopathic condylar resorption. B,Patient with left hemimandibular hypertrophy. C,Early right condylar fracture with abnormal growthof condyle around articular eminence

Fig 7. A, Presurgery, 1-week postsurgery, and 1-yearpostsurgery 3D models of patient treated with maxillaryadvancement and mandibular setback. B, Superimpositionof pre- and postsurgery models showing surface distancesbetween 2 models. Surface of cranial base was used forregistration. Cranial base color map is green (0 mm surfacedistance), showing adequate match of before and aftermodels for cranial base structures. Note that maxilla wasbrought forward as shown in red. Mandibular setbackprecisely maintained rami position, sliding mandibularcorpus posteriorly, with slight counterclockwise rotationto correct open-bite tendency. C, Surface distancesbetween 1-week and 1-year postsurgery models showsvalues close to 0 mm and stability of surgical procedures.

Fig 5. Conventional initial records suggest orthodon-tic treatment in conjunction with maxillary surgeryfor correction of cross-bite and anterior open-bite.A and B, 3D virtual models and display withoutposterior cortical bone show lingual tipping ofmaxillary premolars and molars. Patient was alsooffered orthodontic correction without surgery.

3D Continued from page 23

Image-analysis procedures include construction of 3D models,18 registration and superimposition of models at varioustime points,22 and calculation of the distances between the 3D surfaces.23 The automation of these methods, by usingin-house computer tools, allows image analysis procedures to be largely independent of observer errors.24 The super-imposition methods are fully automated, with voxel-wise rigid registration of the cranial base to avoid observer-depen-dent techniques based on overlap of anatomic landmarks. After the software masks the maxillary and mandibular struc-tures, it compares the grey level intensity of each voxel in the cranial base to register the 2 CT images. These rotation andtranslation parameters are also applied to register 3D models. After registration, we can assess the overlay of the 3Dmodels using Mesh Valmet. MeshValmet 24 software allows visual and quantitative assessment of the location andmagnitude of changes over time segmentation via graphic overlays and calculation of the distances between the surfacesof the 3D models at 2 time points (Fig 7). The resulting 3D graphic display of the structure is color-coded with theregional magnitude of the displacement between 2 segmentations. The pre- or postoperative segmentation results areoverlaid on the CBCT image data for visual comparison. Semitransparency tools can be used for visualization of the 3Doverlays (Fig 8).

Surface distance calculation canbe applied to quantify displace-ment with growth and treat-ment.25 The calculation of surfacedistance for each boundary pointis computationally expensive, be-cause each contour point is com-pared with all the others.MeshValmet calculates all the 3Deuclidean distances from thepresurgery model to the overlaidpostsurgery model, to measure the displacement. This measurement does notreflect properties integrated along the whole boundary and surface. For thesereasons, the measurement of surface distances must be complemented byvisualization of the 3D color-coded maps. The use of shape analysis andsemilandmarks on the surface to incorporate information about vectors nearthe landmark will guide future research on 3D displacement with growth andtreatment. The visualization of 3D model superimposition and the surfacedistance calculations can be used to identify treatment outcomes and stabilityafter treatment.20

Recent AdvancesScanners and softwares have been continuously updated over thelast months. Increased fields of view, ability to navigate throughcross-sectional slices aiding identification of 3D landmarks, fasterrendering, 3D cameras registered to the CBCT acquisition, 3Dsoft tissue paradigm and 3D surgical computer simulation arecurrent areas of research that will hopefully lead to diagnostic andtreatment planning advances ( Figures 9-12) .

Fig 8. Semitransparent overlay of registered 1-week and 1-year postsurgery mandibular models ofpatient in Fig 7. Other anatomic structures are masked for better visualization of changes in mandible.Red, presurgery model; blue, area where pre- and postsurgery models overlap; green, postsurgerymodel.

Fig 9. Surface distance color maps between pre- andpostsurgery models are shown in the top row andbetween pre- and 6 weeks postsurgery in the bottom row.Surface of cranial base was used for registration. Notethat the maxillary advancement is shown in red and themandibular setback in blue. The color maps in the toprow show the postsurgical swelling. The cervical areashows artifacts of change in position of the head indifferent CBCT acquisitions as these models were buildfrom newTom 3G images that were acquired with thepatient head lying down on a pillow.

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REFERENCES1. Halazonetis DJ. From 2-dimensional cephalograms to 3-dimensional computed tomography scans. Am J Orthod Dentofacial Orthop 2005;127:627-37.2. Hatcher DC, Aboudara CL. Diagnosis goes digital. Am J Orthod Dentofacial Orthop 2004;125:512-5.3. Mah J, Hatcher DC. Three-dimensional craniofacial imaging. Am J Orthod Dentofacial Orthop 2004;126:308-9.4. Hajeer MJ, Ayoub AF, Millett DT, Bock M, Siebert JP. Threedimensional imaging in orthognathic surgery: the clinical application of a new method. IntJ Adult Orthod Orthognath Surg 2002;17:318-30.5. Chirani RA, Jacq JJ, Meriot P, Roux C. Temporomandibular joint: a methodology of magnetic resonance imaging 3-D reconstruction. Oral Surg OralMed Oral Pathol Radiol Endod 2004; 97:756-61.6.Ono I, Ohura T, Narumi E, Kawashima K, Matsuno I, Nakamura S, et al. Three-dimensional analysis of craniofacial bones using three-dimensionalcomputer tomography. J Craniomaxillofac Surg 1992;20:49-60.7. Nkenke EN, Zachow S, Benz M, Maier T, Veit K, Benz S, et al. Fusion of computed tomography data and optical 3D images of the dentition for streakartifact correction in the simulation of orthognathic surgery. Dentomaxillofacial Radiology 2004;33: 226-32.8. Kawamata A, Fujishita M, Kuniteru N, Kanematu N, Niwa K, Langlais R. Three-dimensional computed tomography evaluation of postsurgical condylardisplacement after mandibular osteotomy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:371-6.9. Harrell WE Jr, Hatcher DC, Bolt RL. In search of anatomic truth: 3-dimensional digital modeling and the future of orthodontics. Am J OrthodDentofacial Orthop 2002;122:325-30.10. Miller AJ, Koutaro M, Hatcher DC. New diagnostic tools in orthodontics. Am J Orthod Dentofacial Orthop 2004;126:395-6.11. Xia J, Samman N, Yeung RWK, Shen SG, Wang D, Ip HHS, et al. Three-dimensional virtual reality surgical planning and simulation workbench fororthognathic surgery. Int J Adult Orthod Orthognath Surg 2000;15:265-82.12. Cevidanes LHS, Franco AA, Gerig G, Proffit WR, Slice DE, Enlow DH, et al. Assessment of mandibular growth and response to orthopedic treatmentin 3-dimensional magnetic resonance images. Am J Orthod Dentofacial Orthop 2005;128:16-26.13. Cevidanes LHS, Franco AA, Gerig G, Proffit WR, Slice DE, Enlow DH, et al. Relative mandibular growth vectors using high resolution. Am J OrthodDentofac Orthop 2005: 128:27-35.14. Subsol G, Thirion JP, Ayache N. A scheme for automatically building three-dimensional morphometric anatomic atlases: applicationto skull atlas. Med Image Anal 1998;2:37-60.15. Andresen R, Bookstein FL, Conradsen K, Ersboll BK, Marsh JL, Kreiborg S. Surface-bounded growth modeling applied to human mandibles. IEEETrans Med Imaging 2000;19:1053-63.16. Mitteroecker P, Gunz P, Bookstein FL. Semilandmarks in three dimensions. In: Slice DL, editor. Modern morphometrics in physical anthropology.New York: Kluwer Academic Publishers; 2004.17. Ludlow JB, Davies-Ludlow LE, Brooks SL. Dosimetry of two extraoral direct digital imaging devices: NewTom cone beam CT and Orthophos Plus DSpanoramic unit. Dentomaxillofac Radiol 2003;32:229-34.18. http://www.itk.org/index.htm.19. http://www.cc.nih.gov/cip/.20. Takács B, Pieper S, Cebral J, Kiss B, Benedek B, Szijártó G. Facial modeling for plastic surgery using magnetic resonance imagery and 3D surface data.SPIE Electronic Imaging 2004; 18-22 January, San Jose, Calif.21. Heiland M, Habermann CR, Schmelze R. Indications and limitations of intraoperative navigation in maxillofacial surgery. J Oral Maxillofac Surg2004;62:1059-63.22. Maes F, Collignon A, Vandermeulen D, Marchal G, Suetens P. Multimodality image registration by maximization of mutual information. IEEE TransMed Imaging 1997;16:187-98.23. Gerig G, Jomier M, Chakos M. Valmet: a new validation tool for assessing and improving 3D object segmentation. In: Niessen W, Viergever M, editors.MICCAI 2001: Proceedings of the International Society and Conference Series on Medical Image Computing and Computer-Assisted Intervention; 2001Oct 14-17; Utrecht, Netherlands. Berlin: Springer; 2001. p. 516-28.24. Cevidanes LHS, Bailey LTJ, Tucker GR Jr, Styner MA, Mol A, Phillips CL, et al. Superimposition of 3D cone-beam CT models of orthognathicsurgery patients. Dentomaxillofac Radiol 2005; 34:369-75.25. Cevidanes LHS, Bailey LTJ, Tucker SF, Styner MA, Mol A, Phillips CL, et al.Three-dimensional cone-beam CT for assessment of mandibular changesafter orthognathic surgery. Am J Orthod Dentofacial Orthop 2006 (in press).

Fig. 10. Images acquired with 3D facial cameraand Dolphin 10.1 build 8 (courtesy of DDIImaging, California) allows visualization of softtissue structures registered to the CBCT scan.

Fig. 11. Faster rendering with visualization ofboth soft and hard tissue structures (DolphinImaging, California)

Fig. 12. Surgical simulation to plan

displacement of colored segments.

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Radiology Lab Management SystemsSubmitted By: Bill Bradley

RMOX is concerned about image— digital image management that is.As of this summer, Marcelle Jones, owner of Rocky Mountain Oral X-Ray, has embraced the latest innovation inRadiology Lab Management: the ability to create and deliver one CD that includes all images and reports, with justtwo clicks. This tool organizes all digital patient images, across various systems and formats—electronically.RMOX noticed and responded early to the ever-increasing demand for quick, convenient turnaround of patientimages and reports. Traditional film was quickly being replaced with CDs and Internet delivery and RMOX neededto adapt.

Today RMOX produces images from digital cameras, i-CAT, Dolphin, and scanning conventional radiographs.These programs, as well as scheduling and patient files aresituated on different computers. All these stand-alone sys-tems and tools are necessary to run a successful radiologylab, but they also make image and data management morecomplicated, especially with more doctors expecting CDsor Internet delivery. Prior to installing an image manage-ment program like RIMS, all patient information had to bemanually accessed and copied from each individual systemonto a CD for delivery to doctors. This process was diffi-cult across multiple systems, prone to mistakes and ex-tremely time consuming. The CD was simply a single longlist of various static files sent to the doctors. In order toview the information, doctors needed to sift through a list of files, identify their selection correctly, and then openeach one into a program that would display the images and text. So, while the information was still getting out todoctors in a preferable format, it was less than ideal.

The new integrated image management program, the Radiology Image Management System (RIMS), has improvedthings considerably around the lab. Vickie, of RMOX, is delighted with the new program. “What used to take me10 minutes per patient to assemble, now takes less than a minute. And it’s so much easier and always right. Weused to manually create CDs for each patient, which required copying and dragging patient data and images fromeach individual source across our complex network. Now our Radiology Lab Management System knows whereall the images are for each patient.

New Product

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One click from the Patient window pulls the images andreports together to create the CD.” More importantly,Vickie explained that not only does the program make lifeeasier for the lab, but for their customers – the doctors, aswell. A static CD with a long list of files has been replacedwith a single point-and-click navigation window with all filesorganized under three relevant categories: Reports; 3-DAnimations; and Photos. And, to make things even moreuser-friendly, CDs can automatically include viewing soft-ware, like i-CAT Vision. So doctors need not downloadsoftware in order to analyze and manipulate files.

Marcelle initially did not appreciate what a dramatic im-pact the new software would have on their lab processand lab “image”. “My referring doctors used to have toload my CD on their system and find it manually to beable to even see all the files. Many doctors did not knowhow to do this. Then they had to sift though a list of filesto find what they wanted. Now the doctors love the in-terface that pops up automatically and allows them to navi-gate the CD easily. They are using it more than beforebecause it is well organized and easy to use. I am thrilledthat this new tool is helping us be more productive andcustomer-oriented.”

The new Radiology Image Management System soft-ware that RMOX has installed is actually a companionto the popular Radiology Lab Management System thatis currently being used by the majority of Radiology labstoday. As such, program integration is quick, turnkeyand compatible with what most labs are running.

When asked if she is looking at any other lab manage-ment enhancements, Marcelle replied, “Once RMOXhas successfully adapted this new streamlined image andpatient management system for CD delivery, I think wemay take a look at possible Internet delivery. That’llsave our customers another day and mailing costs.” Allthat said, we don’t think Marcelle should be concernedabout image anymore.

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Karen Hauler and Vickie JonesRocky Mountain Oral X-Ray, INC.

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Lead and Lead Foil Recycling

Healthcare Compliance Serviceis a nationwide recycling/dis-posal service company for thehealthcare industry providing avariety of waste handling ser-vices. Lead is used as protec-tion against radiation exposurefrom X-ray equipment. Leadcan be found in many items such as protective clothing,bibs, lead-lined boxes for film, and lead foil in dental of-fices. All of these items when in need to be disposed of,are considered hazardous waste and must be manage assuch. www.hcstoday.com/

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Each set contains 50 com-monly used hanging hole X-ray markers. 12" x 15" wal-nut grain wall board withbrass hooks included. Elitemarkers have long-lastinganodized aluminum casingand letters. 327.00www.alimed.com/

3-D ModelBiomedical Modeling Inc. specializes in the productionof physical solid models from data generated fromMRI or CT scans. BMI Biomodels are custom madeto meet the specific needs of surgeons andprostheticians. We welcome you to contact us withyour concerns and questions, to find out how we canput the power of biomodels in your hands. Biomodelsare accurate, tactile, three-dimensional representationsof patient anatomy. Ourmodels are used forvisualization, surgicalplanning and rehearsal, andimplants and bonegrafts.www.biomodel.com

Lab Products

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