Advancements in digital imaging what is new and on the horizon


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Advancements in digital imaging what is new and on the horizon

  1. 1. Advancements in Digital Imaging : What Is New and on the Horizon? W. Bruce Howerton, Jr. and Maria A. Mora JADA 2008;139;20S-24S The following resources related to this article are available online at ( this information is current as of April 7, 2012): Updated information and services including high-resolution figures, can be found in the online version of this article at: This article cites 9 articles, 3 of which can be accessed free: Downloaded from on April 7, 2012 Information about obtaining reprints of this article or about permission to reproduce this article in whole or in part can be found at: © 2012 American Dental Association. All rights reserved. Reproduction or republication strictly prohibited without prior written permission of the American Dental Association.
  2. 2. Downloaded from on April 7, 2012Advancements in digital imagingWhat is new and on the horizon?W. Bruce Howerton Jr., DDS, MS; Maria A. Mora, DDS, MS ithin the last 20W years, diagnostic digital imaging modalities in den- tistry, includingperiapical, bitewing, panoramic andcephalometric imaging, have beenreplacing conventional (film-based) ABSTRACT Background and Overview. Cone beam computed tomography (CBCT) is a diagnostic imaging technology that is changing the way dental practitioners view the oral and maxillofacial complex. CBCT uses radiation in a similar manner as does conventional diagnosticradiography. Drawbacks of two- imaging and reformats the raw data into Digital Imaging and Com-dimensional (2-D) imaging include munications in Medicine (DICOM) data. DICOM data are importedinherent magnification, distortion into viewing software that enables the manipulation of multiplanarand overlap of anatomy.1 reconstructed slices and three-dimensional volume renderings. As early as the 1920s, manufac- DICOM data also may be used in third-party software to aid in dentalturers attempted to overcome the implant placement, orthognathic surgery and orthodontic assessment.inherent problems of 2-D imaging Conclusions and Clinical Implications. The informationby devising movement of the gained from using CBCT requires careful interpretation to achievereceptor and source in opposite optimum results for the patient and provider.directions to produce tomographic Key Words. Computed tomography; oral and maxillofacial radiog-“slices” of oral and maxillofacial raphy; digital radiography; dental radiography.anatomy; this process is termed JADA 2008;139(6 supplement):20S-24S.“linear” or “multidirectional tomog-raphy.” In the 1990s, researchersused software to reconstruct 2-Dimages of an object from randomangles and distances into a three- Dr. Howerton is in private practice in oral and maxillofacial radiology, Carolina OMF Imaging, 3200 Blue Ridge Road, Suite 218, Raleigh, N.C. 27612, e-mail “”.dimensional (3-D) image in a Address reprint requests to Dr. Howerton.process termed “tuned-aperture Dr. Mora is in private practice in oral and maxillofacial radiology, Carolina OMF Imaging, Raleigh, N.C.20S JADA, Vol. 139 June 2008 Copyright © 2008 American Dental Association. All rights reserved.
  3. 3. computed tomography” (TACT) (Wake Forest capture photons and convert them to electronsUniversity, Winston-Salem, N.C.).1 Abreu and col- that contact a fluorescent screen that emits lightleagues2 found that the diagnostic performance of captured by a charge-coupled device camera.TACT imaging was comparable with that of As the source and receptor rotate once aroundbitewing images with regard to detecting proxi- the patient, many exposures are made, ranging inmal caries in vitro. duration between 8.9 and 40 seconds. The soft- Within the past decade, technology termed ware “reconstructs” the sum of the exposures via“cone beam computed tomography” (CBCT) has algorithms specified by the manufacturer into asevolved that allows 3-D visualization of the oral many as 512 axial slice images. These images areand maxillofacial complex from any plane. This in the Digital Imaging and Communications inimaging modality eliminates the shortcomings of Medicine (DICOM) (National Electrical Manufac-2-D imaging, produces a smaller radiation dose turers Association, Rosslyn, Va.) data format.5than that produced by medical CT and enables DICOM is a standard for handling, storing,clinicians to make more accurate treatment plan- printing and transmitting information in medicalning decisions, which can lead to more successful imaging. During a single rotation of the sourcesurgical procedures.3,4 In this article, we describe and receptor, the receptor captures the entirehow CBCT works, describe its use in dentistry volume of anatomy within the field of view. Downloaded from on April 7, 2012today and envision how it will be used in the Medical CT differs in that it uses a fan-shapedfuture. beam and captures portions or slices of anatomy as the source and receptor move along the longCONE BEAM COMPUTED TOMOGRAPHY axis of the section of anatomy being examined.How CBCT works. Currently available CBCT The clinician imports the DICOM data intounits include the following: 3D Accuitomo FPD viewing software, enabling him or her to seeXYZ Slice View Tomograph (J. Morita USA, axial, coronal and sagittal multiplanar recon-Irvine, Calif.), 3D X-ray CT Scanner Alphard structed images of the volume, as well as 3-DSeries (Asahi, Kyoto, Japan), Quolis Alphard volume renderings. One advantage of using aAlphard-3030-Cone-Beam (Belmont Equipment, DICOM data format is that the dentist can makeSomerset, N.J.), CB MercuRay (Hitachi Medical precise measurements in any plane within theSystems America, Twinsburg, Ohio), Galileos 3D viewing software. DICOM viewers are available(Sirona Dental Systems, Charlotte, N.C.), i-CAT readily and can be downloaded from the Internet(Imaging Sciences International, Hatfield, Pa.), free of charge or purchased from third-partyIluma Ultra Cone Beam CT Scanner (Care- retailers. Figure 1 shows examples of images pro-stream, Rochester, N.Y.), NewTom 3G and VG duced with a third-party DICOM viewer.(AFP Imaging, Elmsford, N.Y.), Picasso (E-woo Another important advantage of CBCT overTechnology, Houston), PreXion 3D (TeraRecon, medical CT is that the amount of radiationSan Mateo, Calif.), ProMax 3D (Planmeca USA, received by the patient is markedly less than theRoselle, Ill.) and Scanora 3D (Soredex, Tuusula, dose received with medical CT units. Ludlow andFinland). In addition, some digital panoramic colleagues6 reported that the effective dose equiv-radiographic systems include CBCT technology. alent measured after an exposure using indirect Although all CBCT units provide 3-D informa- digital panoramic imaging was 6 to 7 microSiev-tion, each manufacturer uses slightly different erts. (The effective dose equivalent is the amountscanning parameters and viewing software. For of radiation received after taking into account theexample, patients may sit, stand or be supine, tissue’s sensitivity to radiation.7 It is calculateddepending on the CBCT unit. The radiation beam by multiplying the dose received by the organs byis 3-D in shape and similar in photon energy to a weighting factor that represents the organs’that used in conventional and digital radiog- sensitivity. One sums up the various doses toraphy. The receptor captures 2-D images and issolid-state (digital) or an image intensifier. Solid-state receptors absorb photons that are converted ABBREVIATION KEY. CBCT: Cone beam computedto an electric charge, which is measured by the tomography. CT: Computed tomography. DICOM:computer. One advantage of solid-state receptors Digital Imaging and Communications in improved photon utilization; one disadvantage TACT: Tuned-aperture computed the high cost of production. Image intensifiers 3-D: Three-dimensional. 2-D: Two-dimensional. JADA, Vol. 139 June 2008 21S Copyright © 2008 American Dental Association. All rights reserved.
  4. 4. A B C Figure 1. OnDemand3DApp software (CyberMed, Seoul, South Korea). A. Hard-tissue evaluation for dental implant planning. B. Three- dimensional (3-D) volume rendering of the anatomy captured within the field of view. C. Sculpting of the 3-D volume rendering with soft- tissue overlay (in this case, the airway space). obtain the effect on the body.) The effective dose the nasal cavity and maxillary sinus, as well as equivalent measured using CBCT is between 30 cortical border erosion of these structures and 400 µSv,6 depending on the manufacturer resulting from apical rarefying osteitis.9 Downloaded from on April 7, 2012 and technical factors involved. This compares DICOM format. Clinicians also can import with an effective dose equivalent of 2,100 µSv the DICOM data format into third-party software from a conventional medical CT scan of the max- that serves as an adjunct in treatment planning. illa and mandible.6 For example, SimPlant (Materialise Dental NV, Uses in dentistry. Dentists can use the infor- Leuven, Belgium) dental implant computer- mation obtained from the data to evaluate hard guided software converts DICOM data into a file tissues for possible dental implant placement that provides information for presurgical plan- and/or grafting, orthodontic treatment planning, ning. The software incorporates computer-aided temporomandibular joint complex evaluation, design/computer-aided manufacturing replicas of pathosis evaluation, demonstration of anatomic dental implants for the clinician to place into the variations and evaluation of patients who have region of interest. The clinician sends the file to a experienced trauma. CBCT can aid in presurgical manufacturing facility, which creates a surgical planning for dental implant placement by local- guide through a process termed “stereolithog- izing the anatomy to be avoided during surgery, raphy.” The guide includes metal cylinders that measuring bone volume precisely and assessing direct osteotomy drills into precise locations in the quality of hard tissue. the maxilla and/or mandible, as planned by the In orthodontics, CBCT can improve clinicians’ software. evaluation of impacted canines and delayed tooth Another computer-guided software that uses eruptions in relationship to adjacent teeth. In fact, CBCT data (Procera Software 2.0, Nobel Biocare a recent study8 demonstrated that, as a result of USA, Yorba Linda, Calif.) allows the dentist to using CBCT, clinicians altered more than one-half place dental implants by using a surgical guide of treatment plans involving canine-related diag- (NobelGuide, Nobel Biocare USA) and a fixed noses. Also, dentists can view the temporo- prosthesis during a single dental visit. Other mandibular joint complex without interference examples of third-party computer-guided DICOM- from surrounding dense temporal bone to demon- compliant software are EasyGuide (Keystone strate erosion, osteophytic formation of the Dental, Burlington, Mass.), ImplantMaster condyle or both. In endodontics, it is difficult at (iDent, Ft. Lauderdale, Fla.) and VIP Virtual times for clinicians to evaluate the extent of infe- Implant Placement Software (Implant Logic Sys- rior cortical border erosion of the maxillary sinus tems, Cedarhurst, N.Y.). Because different practi- or of associated mucosal thickening extending to tioners often are responsible for the placement the periapical region of the roots of maxillary and restoration of dental implants, this tech- teeth using 2-D periapical imaging owing to super- nology enhances communication between practi- imposition of structures. At spatial resolutions of tioners, as well as patients’ understanding and 300 micrometers (0.3 millimeters) and less, education. DICOM-compliant software also aids images produced with CBCT show the position of in orthognathic surgery and 3-D cephalometric the apexes of roots of maxillary teeth extending to analysis. 22S JADA, Vol. 139 June 2008 Copyright © 2008 American Dental Association. All rights reserved.
  5. 5. Figure 2. Images created with Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif.). With this software,three-dimensional objects can be prepared by using preset intensity levels of soft and hard tissue. Once this is accomplished, the clinician canview the object’s skeletal or soft-tissue surfaces by themselves or together. (Reprinted with permission of Dolphin Imaging & ManagementSolutions, Chatsworth, Calif.). Disadvantages of CBCT. Because radiation are required to create 3-D volume images thatfrom the source is transmitted through tissues in confirm 2-D relationships. To ensure the correctthe body, the receptor receives nonuniform infor- and safe use of this technology, educational insti-mation from radiation scattered in many direc- tutions are incorporating CBCT into their cur- Downloaded from on April 7, 2012tions; this is termed “noise.” In addition, radiation ricula, and continuing education courses areis attenuated when passing through dense objects being offered to help dental practitioners use and(such as nonprecious alloys in metal restorations, interpret DICOM data.crowns and titanium materials). Sometimes, radi- In 1999, the American Dental Association rec-ation is attenuated completely and does not reach ognized the specialty of oral and maxillofacialthe receptor. When this “radiation-less” informa- radiology.11 Presently, two-year certificate andtion is reconstructed, streak artifacts in images three-year master’s-level graduate dental spe-are formed that can obstruct the surrounding cialty programs are offered.12 Oral and maxillofa-anatomy. Manufacturers attempt to remove noise cial radiologists are trained to interpret hard-and streak artifacts during reconstruction of the tissue changes within the oral and maxillofacialraw data by using their own specific algorithms complex, and they may distinguish themselves byand filters.10 Another form of image degradation becoming diplomates of the American Board ofis motion artifact, which occurs when a patient Oral and Maxillofacial Radiology. The Americanmoves during the scanning process. Practitioners Academy of Oral and Maxillofacial Radiology hascan reduce patient movement by using head- stated that CT and implant imaging should bestabilizing devices and by providing oral instruc- performed only by a board-certified oral and max-tions to the patient to remain still during the illofacial radiologist or a dentist with adequatescanning process. training or experience.13 Cost. The high cost of CBCT technology pro-hibits its use in most dental offices. CBCT THE FUTURE OF DIAGNOSTIC IMAGINGmachines can range in cost from $150,000 to The future of diagnostic imaging using DICOM$300,000. Thus, purchasers of this technology data is bright. For example, DICOM-complianttypically work in a multidentist practice or an software known as “volumetric imaging software”imaging center servicing a dental community. is being used in orthodontics to merge photo- Training. Many practitioners who incorporate graphic images with radiographic images so thatthis technology into their practices have not had clinicians can assess true soft- and hard-tissuethe training required to interpret anatomy relationships, as shown in Figure 2. Companiesbeyond the maxilla and mandible using 2-D mul- providing this technology include Anatomagetiplanar images reconstructed into three dimen- (San Jose, Calif.), Dolphin Imaging & Manage-sions. They need to recognize calcifications within ment Solutions (Chatsworth, Calif.) andthe cerebral hemispheres, paranasal sinuses and Materialise Dental NV.oropharyngeal regions, as well as soft-tissue For example, consider a patient with a congen-asymmetries. Clinicians must exercise care and ital deformity in the oral and maxillofacial region,draw precise image layer curves, resulting in malocclusion and missing teeth. Using DICOM-orthogonal slices that allow correct measurement compliant software, the oral surgeon, orthodon-of anatomical relationships. Also, time and skill tist, implantologist and restorative dentist can JADA, Vol. 139 June 2008 23S Copyright © 2008 American Dental Association. All rights reserved.
  6. 6. link their communication such that pretreatment dimensional dento-alveolar imaging. Dentomaxillofac Radiol 1997;26(1):53-62.expectations equal posttreatment results. 2. Abreu M Jr, Yi-Ching L, Abreu AL. Comparative diagnostic per- Finally, dental imaging centers staffed with formance of TACT slices and its multiple source images: an in vitro study. Dentomaxillofac Radiol 2004;33(2):93-97.board-certified oral and maxillofacial radiologists 3. Nakajima A, Sameshima GT, Arai Y, Homme Y, Shimizu N,will become more commonplace, providing patient Dougherty H Sr. Two- and three-dimensional orthodontic Imaging using limited cone beam-computed tomography. Angle Orthodcare that includes acquisition, interpretation and 2005;75(6):895-903.conversion of DICOM data. In addition, oral and 4. Cotton T, Geisler T, Holden D, Schwartz S, Schindler W. Endodontic applications of cone-beam volumetric tomography.maxillofacial radiologists will be charged with 2007;33(9):1121-1132.educating the private practice dental community 5. Digital Imaging and Communications in Medicine. DICOM. Rosslyn, Va.: NEMA. “”. Accessed April 16,about the advantages of using DICOM data for 2008.better patient care. 6. Ludlow JB, Davies-Ludlow LE, Brooks SL, Howerton WB. Dosimetry of 3 CBCT devices for oral and maxillofacial radiology: CB Mercuray, NewTom 3G and i-CAT. Dentomaxillofac RadiolCONCLUSION 2006;35(4):219-226. 7. International Commission on Radiological Protection (ICRP).Two-dimensional diagnostic imaging has served “”. Accessed April 16, 2008.dentistry well and will continue to do so for the 8. Bjerklin K, Ericson S. How a computerized tomography exami- nation changed the treatment plans of 80 children with retained andforeseeable future. However, the advent of CBCT ectopically positioned maxillary canines. Angle Orthod 2006;76(1):allows complete visualization of the oral and max- 43-51. Downloaded from on April 7, 2012 9. Hauman CH, Chandler NP, Tong DC. Endodontic implications ofillofacial complex. Through education regarding the maxillary sinus: a review. Int Endod J 2002;35(2):127-141.the correct interpretation of data and training in 10. Tu S, Shaw C, Chen L. Simulation of cone beam computer tomog- raphy chest imaging with parallel computing: nodule detectabilitythe scanning process, better treatment planning versus dose. Physics Medical Imaging 2005;5745:910-920.and surgical treatment will result. The future of 11. American Dental Association. Dental professionals. Specialty National Organizations. “ technology lies within an increased number specorgs.asp”. Accessed April 2, 2008.of imaging centers staffed with oral and maxillo- 12. American Academy of Oral and Maxillofacial Radiology. Directory of advanced educational programs. “”.facial radiologists who understand the needs of Accessed April 2, 2008.dentists, as well as the benefits of using DICOM- 13. White SC, Heslop EW, Hollender LG, Mosier KM, Ruprecht A, Shrout MK; American Academy of Oral and Maxillofacial Radiology, adcompliant software. hoc Committee on Parameters of Care. Parameters of radiologic care: an official report of the American Academy of Oral and Maxillofacial Disclosure. Drs. Howerton and Mora did not report any disclosures. Radiology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91(5):498-511. 1. Webber RL, Horton RA, Tyndall DA, Ludlow JB. Tuned-aperturecomputer tomography (TACT): theory and application for three-24S JADA, Vol. 139 June 2008 Copyright © 2008 American Dental Association. All rights reserved.