PANORAMIC Imaging Volume 1, Issue 1News $4.50US Editor: How did this Newsletter get started? Allan G. Farman, B.D.S., PhD (odont.), D.Sc (odont.), By Dr. Allan G. Farman at this time. Diplomate of the American Board During the Chicago Midwinter meeting It is for this reason that I agreed to edit a of Oral and Maxillofacial earlier this year, I was asked by newsletter on panoramic radiography that Radiology, Professor of Radiology representatives from Panoramic Corporation would be distributed as a service to the and Imaging Sciences, if I could recommend a good general dental profession. My agreement is Department of Surgical and contingent upon editorial independence, Hospital Dentistry, The University textbook on panoramic radiography. of Louisville School of Dentistry, Apparently there is a great deal of interest strict avoidance of commercial content, and Louisville, KY. within the dental profession in obtaining a focus on the interpretation of panoramic clinically relevant information on how to radiographs in general rather than achieve the maximum diagnostic yield from radiographs made using a machine from the panoramic radiograph. On my personal one particular vendor. Each issue will library shelf, I have several texts on contain three to five-and-a-half pages of Featured Article: panoramic radiography published by such content, mostly devoted to one topic in each case. There will also be selected Panoramic Interpretation eminent sources as Manson-Hing, Langlais and Chomenko; however, when I looked at clinically relevant abstracts from the the dates of publication inside the front scientific literature. The final half-to-one In the Recent Literature: covers of these books, I was disappointed page will be a user’s technical guide in Periodontal Disease to find that the latest revision was made which Panoramic Corporation staff provide more than a decade ago. A thorough useful tips and other information specific to Ridge Assessment search of the World Wide Web, including the Panoramic Corporation PC-1000. Osteoporosis “Bestbookbuys.com” showed that I was not Again, there will be no comparisons made mistaken in thinking that there is no between brands. The intent of this Atherosclerosis available text based upon modern Newsletter is to be a resource for the dental Developmental Anomalies panoramic technology. No easy-to-access, profession rather than an advertisement. up-to-date resource on panoramic You may wish to collect successive F.A.Q.’s: radiography exists in the English language Newsletters in a ring binder as a reference. Light Films Dark Films Getting the most out of panoramic Anterior Whiteout radiographic interpretation. Quality assurance badly. Most errors are due to incorrect As with any other radiographic method, patient positioning, leading to excessive optimum interpretable diagnostic images and sometimes disproportionate distortion. can only be achieved with careful quality A correctly positioned patient’s panoramic assurance in patient positioning, in radiograph generally shows symmetry of selecting appropriate exposure parameters the size of the mandibular rami and Provided as a professional service by: and during processing. While panoramic condyles, and the dental segments are “in Panoramic Corporation radiography is easy to perform well focus” with a gentle downward convexity of [email protected] provided all the manufacturer’s instructions the maxillary archs. Provided the patient bit are followed, it is equally easy to perform correctly on the biteblock, the anterior Panoramic Imaging News “You can sequence your evaluation in many ways; however, it is very important to develop a consistent approach that ensures that all diagnostic information in the radiograph is indeed read.” structures are portrayed in the midline and Interpreting a normal the apices of the mandibular incisor teeth panoramic radiograph should be in full “focus.” Provided that the A normal panoramic radiograph contains a tongue is kept up in the roof of the mouth substantial amount of information. Figure 7 during exposure, the roots of the maxillary is the PC-1000 (Panoramic Corporation, teeth are clearly demonstrated. It is less Fort Wayne, Indiana) panoramic radiograph expensive in time and materials - and in of a 12-year male patient. Fifty distinct soft radiation to the patient - to perfect your Fig.1. A panoramic radiograph simultaneously tissues, bony and dental landmarks have panoramic technique, than to make presents views from both sides of the patients face been labeled on this radiograph. When was as well as providing a frontal perspective. unnecessary repeat exposures. And the the last time that you consciously and diagnostic yield from an excellent thoroughly inspected all of the structures panoramic radiograph is far superior to one that are demonstrated? As you probably are made under less rigorous quality controls. making the radiograph with the intent of dental diagnosis at the forefront, the dental Image projection geometry arches should be left to last in your systematic evaluation of the image. You can To gain the maximum amount of diagnostic sequence your evaluation in many ways; information from a dental panoramic however, it is very important to develop a radiograph (pantomograph), it is necessary consistent approach that ensures that all to understand that panoramic radiographs diagnostic information in the radiograph is are “flattened out” schemes of a curved indeed read. To see all of the subtle image layer. Think of the plan view of the Fig. 2. You can best understand the relative position variations in contrast, it is imperative that of structures shown in a panoramic radiograph if you head (Fig. 1). The panoramic radiograph (1) a view box be used (preferably having imagine the film to be bent around the patients face. provides a plan of one side, then the a variable light intensity), (2) any midline, then the other side of the face and extraneous light from the view box be jaws. Imagine the panoramic film wrapped blocked out, and (3) the diagnostic around the outside of the face. The actual evaluation is performed under subdued panoramic film seems large in comparison ambient lighting away from distractions. It with the 3M human phantom (Fig. 2). This is suggested that you review all panoramic is because the actual image from most radiographs made in a given day when all panoramic systems is enlarged by about patients have left the practice. It will be 20 %. Figures 3 and 4 show a printed Fig. 3. The lateral and more posterior structures are surprising how much can be gained from panoramic image reduced to life size projected to each side of the panoramic radiograph. such a second look when the atmosphere is superimposed on the phantom. These likely to be more relaxed! graphically explain the association between the panoramic radiograph and the represented structures. In reality the image I approach reading the radiograph roughly is formed section by section behind the in the numerical sequence shown in Figure secondary slit. Figure 5 illustrates this 7; namely starting with the bony landmarks process by putting the same printed from the midline of the upper jaw and nasal panoramic image in place of the film cavity, then working back in the maxilla and cassette. The relative movement of the x-ray zygomatic complex on each side. The soft source and the “camera” during exposure tissue shadows of the tongue and soft creates the effect of “wrapping the film palate are incorporated at this stage. This is Fig. 4. The anterior structures are shown in the about the patient’s face” (Fig. 6). followed by evaluation of the cervical spine midline of the standard panoramic projection. Panoramic Imaging News [email protected] Fig. 5. The panoramic image is formed sequentially from information passing through the machine’s secondary slit. The film moves past the secondary slit at the appropriate rate necessary to minimize mechanical distortion. Fig. 6. The panoramic latent image is created as the film cassette moves past the secondary slit. The production of the latent image is simulated using the print of a panoramic radiograph. Fig. 7. Annotated panoramic radiograph. and associated structures. I then evaluate Anatomical Comparisons the contents of the mandible starting from Using the same numerical key as that for the midline and then progressing posteriorly the annotated radiograph (Fig. 7), Figures 8 on each side. Any examination would be and 9 show the normal anatomical incomplete without a thorough evaluation of Fig. 8. Annotated lateral view of phantom. structures viewed from the lateral and frontal the soft tissues anterior to the spine and facial aspects of a 3M phantom. It should inferior to the mandible. [The evaluation of be remembered that the radiograph shows this space will be the main subject of the all features within the panoramic image next issue of this Newsletter.] The last part layer whether facial or lingual. It should of the evaluation should be the area of chief also be remembered that only the structures complaint and the dental arches. that are within the selected image layer will be in “focus.” This image layer is generally narrower for the anterior regions than for the posterior segments. Fig. 9. Annotated anterior view of phantom. 1-800-654-2027 Key To Annotation of Panoramic Image In Figure 7 1. Nasal Septum 25. Mandibular Foramen and Lingula 2. Anterior Nasal Spine 26. Mandibular Canal 3. Inferior Turbinate 27. Mental Foramen 4. Middle Turbinate 28. Inferior Border of Mandible 5. Superior Turbinate 29. Hyoid 6. Soft Tissue Shadow of the Nose 30. Pharyngeal Airspace 7. Airspace between Soft Tissue 31. Epiglottis Shadow of Upper Border of 32. Coronoid Process of Mandible Tongue & Hard Palate 33. Inferior Orbital Rim 8. Lateral Wall of Nasal Passage 34. Mastoid Process 9. Maxillary Sinus (Antrum) 35. Middle Cranial Fossa 10. Nasolacrimal Canal Orifice 36. Biteblock for Patient Positioning 11. Orbit During Panoramic Radiography 12.