Computed Tomography: CT & CBCT **Dr Dayea Oh** OMF Radiologist   Computed Tomography: CT & CBCT **Dr Dayea Oh** OMF Radiologist Clinical photograph of a CBCT (Cone Beam Computed Tomography) scanner unit. The image shows the C-arm gantry structure with an X-ray tube and detector assembly, mounted on a vertical column. A patient chair is visible at the base, positioned for head or facial imaging. This equipment corresponds to the 'CBCT' mentioned in the title. Clinical photograph of a standard medical CT (Computed Tomography) scanner. The image displays the large circular gantry with the bore opening, and the patient bed extending outwards towards the viewer. This equipment corresponds to the 'CT' mentioned in the title. # Learning Objectives - To understand the basic theory of computed tomography - What is Hounsfield Unit? - What are the indications for Multislice CT? - What are the indications for Cone Beam CT? - What are the CBCT artefacts? - What are the differences between Multislice CT and Cone Beam CT? - To understand the basic theory of computed tomography - What is Hounsfield Unit? - What are the indications for Multislice CT? - What are the indications for Cone Beam CT? - What are the CBCT artefacts? - What are the differences between Multislice CT and Cone Beam CT? Advanced Imaging Modalities in DMFR - Multi-slice / Multi-detector Computed Tomography (MSCT / MDCT) - Cone Beam Computed Tomography (CBCT) - Magnetic Resonance Imaging (MRI) - Ultrasound - Nuclear Medicine Imaging (NMI) - Multi-slice / Multi-detector Computed Tomography (MSCT / MDCT) - Cone Beam Computed Tomography (CBCT) - Magnetic Resonance Imaging (MRI) - Ultrasound - Nuclear Medicine Imaging (NMI) **Computed Tomography, CT** * Invented in 1971 by Sir Godfrey Hounsfield * First CT scan was Brain CT * Fan-shaped, continuous, rotational x-ray beam * “Slices” of cross-sectional / transverse / axial images * Hundreds to thousands of acquired slices are later **reconstructed** (= digitally stacked together) to from volumetric imaging <TUBE/DETECTOR ASSEMBLY ROTATES AROUND PATIENT> <X-RAY TUBE> <PATIENT TABLE MOVES INTO GANTRY> <MULTIPLE ROWS OF DETECTORS>   **Computed Tomography, CT** - Invented in 1971 by Sir Godfrey Hounsfield - First CT scan was Brain CT - Fan-shaped, continuous, rotational x-ray beam - “Slices” of cross-sectional / transverse / axial images - Hundreds to thousands of acquired slices are later **reconstructed** (= digitally stacked together) to form volumetric imaging <TUBE/DETECTOR ASSEMBLY ROTATES AROUND PATIENT> <X-RAY TUBE> <PATIENT TABLE MOVES INTO GANTRY> <MULTIPLE ROWS OF DETECTORS> Labeled diagram illustrating the CT scanning process. The image shows a patient head positioned in the gantry with a fan-shaped x-ray beam originating from the X-ray tube and passing through to multiple rows of detectors on the opposite side. Callouts identify the 'TUBE/DETECTOR ASSEMBLY ROTATES AROUND PATIENT', 'X-RAY TUBE', 'PATIENT TABLE MOVES INTO GANTRY', and 'MULTIPLE ROWS OF DETECTORS'. This visual demonstrates the rotational acquisition method described in the text. Diagram showing a top-down view of a patient lying on a table inside the CT gantry. An X-ray source emits a beam (indicated by an arrow) towards detectors arranged in a circular array around the patient. Blue arrows indicate the rotation of the assembly and the movement of the table. This figure complements the first diagram by showing the spatial arrangement of the components mentioned in the text.    Diagram illustrating the relationship between Picture elements (pixels), Slice width, and Volume elements (voxels) in a CT scan. It features a central cross-sectional image of a chest with grid overlays, pointing to specific pixels and voxels. A Hounsfield unit scale is visible on the right, mapping grey values to tissues like Bone, Soft tissue, Water, Fat, Lung tissue, and Air. Flowchart-style diagram demonstrating the process of voxel reconstruction. It shows a progression from a patient head phantom (A) through a slice grid (B), to a single voxel block (C), then a sequence of voxels (D), and finally reconstructing the volume within a grid (E). Arrows indicate the flow of data or reconstruction steps. Composite clinical photo showing three distinct CT scan views of a human head/neck labeled A, B, and C. Panel A is a sagittal view showing the profile of the skull, jaw, and cervical spine. Panel B is a coronal view displaying the nasal cavity, sinuses, and orbits. Panel C is an axial view showing the base of the skull and temporal bones.    An anatomical diagram illustrating the Axial plane. It shows a stylized human figure viewed from above with arms raised, and a horizontal blue cutting plane across the torso. An arrow points from the intersection to an inset grayscale CT scan image of an axial cross-section of the abdomen. An anatomical diagram illustrating the Coronal plane. It shows a stylized human figure viewed from the front with arms raised, and a vertical blue cutting plane passing through the body from left to right. An arrow points from the intersection to an inset grayscale CT scan image showing a coronal view of the internal organs. An anatomical diagram illustrating the Sagittal plane. It shows a stylized human figure viewed from the side with arms raised, and a vertical blue cutting plane slicing the body into left and right halves. An arrow points from the intersection to an inset grayscale CT scan image showing a sagittal view of the spine and torso. 3D Imaging Orientation - Terminology • Anterior • Posterior • Superior • Inferior • Medial • Lateral • Superficial • Deep • Ipsilateral • Contralateral **Right** **Left** **MRI images** **Axial** **(transverse)** **Sagittal** **Coronal** <div><table> | **Coronal** | **Sagittal** | |---|---| | **Plane** | | | **Body** | | | **Right** | | | **Plane** | **Left** | | **Sagittal** | | | **Plane** | | | **Axial** | | | **Body** | | | **Plane** | | </table></div>    3D Imaging Orientation - Terminology - Anterior - Posterior - Superior - Inferior - Medial - Lateral - Superficial - Deep - Ipsilateral - Contralateral **Right** **Left** **MRI images** **Axial** **(transverse)** **Sagittal** **Coronal** | Coronal | Sagittal | |---------|----------| | Plane | | | Body | | | Right | | | Plane | Left | | Sagittal| | | Plane | | | Axial | | | Body | | | Plane | | Anatomical diagram illustrating the three primary imaging planes of the human body. The figure shows a standing human silhouette overlaid with three intersecting blue planes: the Coronal Plane (vertical, front-to-back), the Sagittal Plane (vertical, left-to-right), and the Axial Plane (horizontal). Labels point to each plane. A single axial MRI scan of a brain. It is labeled 'Right' on the left side of the image and 'Left' on the right side, demonstrating standard radiological orientation where the viewer's left corresponds to the patient's right. A scale marker '120' is visible in the bottom right corner. A composite figure containing three distinct MRI views of the brain arranged horizontally. From left to right: an Axial (transverse) view showing horizontal slices; a Sagittal view showing a side profile cut; and a Coronal view showing a frontal slice. Each sub-image is labeled at the bottom with its respective anatomical plane name. Modern CT Machine * Helical CT * 3rd generation * Multi-detector CT aka Multislice CT * V Fast scan time (~ 1 second to scan jaws) * X-ray tube & detectors continuously revolve around the patient while the patient table moves through the gantry * Continuous helix of data is acquired as the x-ray beam moves down the patient * Patient in supine (face up) / prone (face down) position on motorised table Rotating gantry ("donut" containing rotating beam & receptor)   Modern CT Machine - Helical CT - 3rd generation - Multi-detector CT aka Multislice CT - Very fast scan time (~ 1 second to scan jaws) - X-ray tube & detectors continuously revolve around the patient while the patient table moves through the gantry - Continuous helix of data is acquired as the x-ray beam moves down the patient - Patient in supine (face up) / prone (face down) position on motorised table Rotating gantry ("donut" containing rotating beam & receptor) Diagram of a patient inside a CT scanner gantry. The patient is lying on a table with their legs inserted into the circular opening (gantry). An arrow points to the rotating component labeled 'Rotating gantry ('donut' containing rotating beam & receptor)' in the OCR text. Diagram illustrating the helical scanning process. A patient lies on a motorized table moving through a rotating gantry. Dashed lines indicate the path of the X-ray beam and detectors as they revolve around the patient while the table moves forward, creating a continuous helix of data acquisition. CT Applications – Head and Neck *Trauma* *Pathology* * Jaw pathology (cysts, tumours, malignancies, etc.) * Sinus pathology * Salivary gland pathology * Oral cancer *ON* *Non-specific dental pain* * Rule out neuropathic pain * Dentistry (low dose protocol) * Implant dentistry *Other:* * Special needs dentistry **Not used in General Dentistry** CT Applications – Head and Neck - **Trauma** - **Pathology** - Jaw pathology (cysts, tumours, malignancies, etc.) - Sinus pathology - Salivary gland pathology - Oral cancer - **ON** - **Non-specific dental pain** - Rule out neuropathic pain - **Dentistry (low dose protocol)** - Implant dentistry - **Other:** - Special needs dentistry **Not used in General Dentistry** CT Workflow • Referral • Protocol • Acquisition (scan) • Data preprocessing • Reconstruction • Interpretation • Report  CT Workflow - Referral - Protocol - Acquisition (scan) - Data preprocessing - Reconstruction - Interpretation - Report Clinical photograph of a CT scan room showing the workflow in action. In the foreground, a technician is seated at a control console with multiple monitors displaying medical imaging data (axial and coronal slices) and control panels. Through the window, a patient is visible on the scanner bed entering the gantry, attended by a radiographer. # Cone Beam CT Cone Beam CT # Figure describing Fan Beam, Cone Beam, and Reconstruction CT scanning methods <b>Fan Beam CT</b> Used in 'conventional' Spiral CT <b>Cone Beam CT</b> <b>Rectangular</b> <b>collimator</b> <b>X-ray flat panel detector</b> <b>Axis of rotation</b> <b>Trajectory arc</b> <b>Object</b> <b>Tubehead</b> <b>Basis Projection</b> <b>Projection data</b> <b>Secondary Reconstructions</b> <b>voxel</b>     Figure describing Fan Beam, Cone Beam, and Reconstruction CT scanning methods - **Fan Beam CT**: Used in 'conventional' Spiral CT - **Cone Beam CT** - **Rectangular collimator** - **X-ray flat panel detector** - **Axis of rotation** - **Trajectory arc** - **Object** - **Tubehead** - **Basis Projection** - **Projection data** - **Secondary Reconstructions** - **voxel** Diagram comparing Fan Beam CT (left) and Cone Beam CT (right). The left panel shows a fan-shaped X-ray beam used in conventional Spiral CT. The right panel shows a cone-shaped X-ray beam. Detailed schematic of the Cone Beam CT setup. Labels include: 'X-ray flat panel detector', 'Axis of rotation', 'Rectangular collimator', 'Tubehead', 'Object' (skull), and 'Trajectory arc'. It illustrates the rotation path of the tubehead around the object to capture projection data. Illustration of the reconstruction process from projections to a cross-sectional image. It shows X-rays passing through a skull object, projecting onto detectors, and resulting in a grayscale tomographic slice of the jaw area. Diagram explaining voxel-based reconstruction. It shows 'Basis Projection' data forming a cube, labeled as 'Projection data', which leads to 'Secondary Reconstructions'. A zoomed-in view highlights a single 'voxel' within the reconstructed 3D volume of the skull. **CBCT Machine** * **Early** * Similar design to **MDCT** * Supine * Fixed table (not mobile) * **Modern CBCT** * Compact design * Some are similar to **PR units** * Stand-up or Seated    - **Early** - Similar design to **MDCT** - Supine - Fixed table (not mobile) - **Modern CBCT** - Compact design - Some are similar to **PR units** - Stand-up or Seated Clinical photo of an early CBCT machine. It features a large gantry with a diamond-shaped aperture and a fixed patient table, consistent with the 'Early' section text describing a design similar to MDCT with a supine position. Clinical photo of a modern CBCT unit designed for seated patients. The image shows a compact stand-up unit with a chair, matching the description of 'Modern CBCT' having a 'Compact design' and being suitable for 'Seated' positions. Clinical photo of another modern CBCT unit, likely a PR (Panoramic Radiography) style unit used for dental imaging. This corresponds to the text noting that some modern units are 'similar to PR units'. The device includes a chin rest and head support mechanism. **Imaging Sciences iCAT FLX** **CBCT** **Morita Veraview X800** **CBCT** **Kavo OP 3D Pro** **Panoramic** **KaVo OP 3D Pro** **Planmeca ProMax 3D CBCT** **Family** **Spatial Resolution & Voxel Size** Large field of view (FOV) Small FOV **Voxel size 0.2 mm** **Voxel size 0.3 mm** **Voxel size 0.4 mm**    **Example CBCT Machines** - Imaging Sciences iCAT FLX CBCT - Morita Veraview X800 CBCT - Kavo OP 3D Pro Panoramic - KaVo OP 3D Pro - Planmeca ProMax 3D CBCT Family **Spatial Resolution & Voxel Size** - Large field of view (FOV) - Small FOV - Voxel size 0.2 mm - Voxel size 0.3 mm - Voxel size 0.4 mm Row of five clinical photos showing different CBCT imaging machines: Imaging Sciences iCAT FLX CBCT, Morita Veraview X800 CBCT, Kavo OP 3D Pro Panoramic, KaVo OP 3D Pro, and Planmeca ProMax 3D CBCT Family. Comparison figure labeled 'Large field of view (FOV)' and 'Small FOV'. Top row shows skull models with red outlines indicating scan volumes. Bottom row shows corresponding rendered images: full skull for large FOV (A, B) and partial jaw/teeth for small FOV (C, D). Figure titled 'Spatial Resolution & Voxel Size' showing three side-by-side CT slices of teeth at different voxel sizes: 0.2 mm, 0.3 mm, and 0.4 mm. Demonstrates how resolution changes with voxel size. # Indications for CBCT in Dentistry **• Dental Trauma** * Root fractures **• Third molar assessment** **• Supernumerary teeth** **• Impacted Canines** **• Implant assessment** **• Periodontal assessment** * 3D bone loss **• Complex endodontic therapy** * High res for root canal morphology **• Root resorption** **• Orthodontic assessment** **• Orthognathic surgical planning** **• Digital dentistry** * 3D printing eg. surgical guides **• TM Joint (limited to osseous)** **• Pathology (limited to osseous)** - **Dental Trauma** - Root fractures - **Third molar assessment** - **Supernumerary teeth** - **Impacted Canines** - **Implant assessment** - **Periodontal assessment** - 3D bone loss - **Complex endodontic therapy** - High res for root canal morphology - **Root resorption** - **Orthodontic assessment** - **Orthognathic surgical planning** - **Digital dentistry** - 3D printing eg. surgical guides - **TM Joint (limited to osseous)** - **Pathology (limited to osseous)** • Effective Radiation Dose • Background at sea level: 1.5mSv / year in Australia • 1 PA is approximately 0.004 mSv (1 day of background radiation) • 1 OPG: 0.008 – 0.01 mSv (2-3 days of background radiation) • 1 Lat Ceph: ~0.005 mSv • **CBCT dose varies and largely depends on FOV, voxel size, mA, kVp, rotation trajectory, etc.** • iCAT large FOV (maxillofacial region): ~0.07 mSv (2-3 weeks of background radiation) • Planmeca 3D small FOV: ~0.03mSv (1 week of background radiation) • Note: the radiation dosage of high resolution, small FOV can be as high as standard large FOV • *Low dose MSCT dosage is comparable to CBCT dosage*  #### Effective Radiation Dose - Background at sea level: 1.5mSv / year in Australia - 1 PA is approximately 0.004 mSv (1 day of background radiation) - 1 OPG: 0.008 – 0.01 mSv (2-3 days of background radiation) - 1 Lat Ceph: ~0.005 mSv - **CBCT dose varies and largely depends on FOV, voxel size, mA, kVp, rotation trajectory, etc.** - iCAT large FOV (maxillofacial region): ~0.07 mSv (2-3 weeks of background radiation) - Planmeca 3D small FOV: ~0.03mSv (1 week of background radiation) - Note: the radiation dosage of high resolution, small FOV can be as high as standard large FOV - *Low dose MSCT dosage is comparable to CBCT dosage* Screenshot of a CBCT control panel interface displaying scan parameters. The image shows 'Scan Time 17.5 sec' and 'CTDIvol 5.32 mGy'. A central diagram illustrates the Field of view size and Rotation trajectory (180° / 360°). Exposure factors are listed as 90 kV, 4.0 mA, and 0°. Scan mode options include Std, Hi-Fi, Hi-Res, and Hi-Speed. CBCT Data Display • Standard display (Orthogonal / Multiplanar view) • Axial • Coronal • Sagittal Planmeca Romexis  CBCT Data Display - Standard display (Orthogonal / Multiplanar view) - Axial - Coronal - Sagittal Planmeca Romexis Multiplanar CBCT data display showing orthogonal views. Panel A shows a facial photo with overlaid axial (red), coronal (green), and sagittal (blue) planes. Panel B is a coronal view of the maxilla/sinuses. Panel C is a sagittal view of the lateral skull base. Panel D is an axial view of the nasal cavity/maxilla. # Axial CBCT Anatomy ## Top Left Panel * (Anatomical diagram labels) A, B, C, D, E **1. Frontal sinus** **2. Frontal bone** **3. Anterior cranial fossa** **4. Squamous portion of temporal bone** **5. Crista galli** **6. Orbit** **7. Greater wing of sphenoid bone** **8. Nasal bone** **9. Anterior ethmoid air cells** **10. Perpendicular plate of ethmoid bone** **11. Posterior ethmoid air cells** **12. Optic canal** **13. Superior orbital fissure** **14. Nasal process of maxillary bone** **15. Uncinate process** **16. Sphenethmoid recess** **17. Sphenoid sinus** **18. Floor of sella turcica** **19. Nasolacrimal duct** **20. Superior turbinate** **21. Inferior orbital fissure** **22. Middle cranial fossa** ## Top Middle-Right Panel * (Anatomical diagram labels) A, B, C, D, E **1. Nasal septum** **2. Nasolacrimal duct** **3. Maxillary sinus** **4. Nasal turbinate** **5. Zygomatic process of maxilla** **6. Zygomaxillary suture** **7. Zygomatic arch** **8. Pterygopalatine fossa** **9. Greater wing of sphenoid bone** **10. Carotid canal** **11. Petrous portion of temporal bone** **12. Internal auditory canal** **13. Infraorbital canal** **14. Lateral wall of maxillary sinus** **15. Pterygomaxillary fissure** **16. Foramen ovale** **17. Foramen spinosum** **18. Glenoid fossa** **19. Mandibular condyle** **20. Carotid canal** **21. Infraorbital foramen** **22. Nasal cavity** **23. Pterygoid plates** **24. Nasopharyngeal airway** **25. Occipital bone** **26. Jugular foramen** **27. Medial wall of maxillary sinus** **28. Coronoid process** **29. Pharyngeal wall** **30. External auditory meatus** **31. Mastoid process** **32. Anterior nasal spine** **33. Nasopalatine canal** **34. Hard palate** **35. Intermaxillary suture** **36. Ramus of mandible** **37. Anterior arch of atlas (C1)** **38. Foramen magnum** ## Top Right Panel * (Anatomical diagram labels) A, B, C, D, E **1. Incisive foramen** **2. Tongue** **3. Maxillary tuberosity** **4. Soft palate** **5. Oropharyngeal airway** **6. Styloid process** **7. Anterior arch of atlas (C1)** **8. Odontoid process of C2** **9. Ramus of mandible** **10. Mandibular foramen** **11. Inferior body of C2** **12. Transverse foramen** **13. Lamina of C2** **14. Mandibular symphysis** **15. Genial tubercles** **16. Mental foramen** **17. Epiglottis** **18. Body of hyoid bone** **19. Greater cornu of hyoid bone** **20. C2-C3 neural foramen** **21. Superior articular process of C3** **22. Inferior articular process of C2**       #### Top Left Panel - (Anatomical diagram labels) A, B, C, D, E **1.** Frontal sinus **2.** Frontal bone **3.** Anterior cranial fossa **4.** Squamous portion of temporal bone **5.** Crista galli **6.** Orbit **7.** Greater wing of sphenoid bone **8.** Nasal bone **9.** Anterior ethmoid air cells **10.** Perpendicular plate of ethmoid bone **11.** Posterior ethmoid air cells **12.** Optic canal **13.** Superior orbital fissure **14.** Nasal process of maxillary bone **15.** Uncinate process **16.** Sphenethmoid recess **17.** Sphenoid sinus **18.** Floor of sella turcica **19.** Nasolacrimal duct **20.** Superior turbinate **21.** Inferior orbital fissure **22.** Middle cranial fossa #### Top Middle-Right Panel - (Anatomical diagram labels) A, B, C, D, E **1.** Nasal septum **2.** Nasolacrimal duct **3.** Maxillary sinus **4.** Nasal turbinate **5.** Zygomatic process of maxilla **6.** Zygomaxillary suture **7.** Zygomatic arch **8.** Pterygopalatine fossa **9.** Greater wing of sphenoid bone **10.** Carotid canal **11.** Petrous portion of temporal bone **12.** Internal auditory canal **13.** Infraorbital canal **14.** Lateral wall of maxillary sinus **15.** Pterygomaxillary fissure **16.** Foramen ovale **17.** Foramen spinosum **18.** Glenoid fossa **19.** Mandibular condyle **20.** Carotid canal **21.** Infraorbital foramen **22.** Nasal cavity **23.** Pterygoid plates **24.** Nasopharyngeal airway **25.** Occipital bone **26.** Jugular foramen **27.** Medial wall of maxillary sinus **28.** Coronoid process **29.** Pharyngeal wall **30.** External auditory meatus **31.** Mastoid process **32.** Anterior nasal spine **33.** Nasopalatine canal **34.** Hard palate **35.** Intermaxillary suture **36.** Ramus of mandible **37.** Anterior arch of atlas (C1) **38.** Foramen magnum #### Top Right Panel - (Anatomical diagram labels) A, B, C, D, E **1.** Incisive foramen **2.** Tongue **3.** Maxillary tuberosity **4.** Soft palate **5.** Oropharyngeal airway **6.** Styloid process **7.** Anterior arch of atlas (C1) **8.** Odontoid process of C2 **9.** Ramus of mandible **10.** Mandibular foramen **11.** Inferior body of C2 **12.** Transverse foramen **13.** Lamina of C2 **14.** Mandibular symphysis **15.** Genial tubercles **16.** Mental foramen **17.** Epiglottis **18.** Body of hyoid bone **19.** Greater cornu of hyoid bone **20.** C2-C3 neural foramen **21.** Superior articular process of C3 **22.** Inferior articular process of C2 Anatomical diagram and corresponding axial CBCT slice. The top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E indicating slice levels. Below is the CT image (labeled B) with numbered callouts: 1. Frontal sinus, 2. Frontal bone, 3. Anterior cranial fossa, 4. Squamous portion of temporal bone, 5. Crista galli, 6. Orbit, 7. Greater wing of sphenoid bone, 8. Nasal bone, 9. Anterior ethmoid air cells, 10. Perpendicular plate of ethmoid bone, 11. Posterior ethmoid air cells. Anatomical diagram and corresponding axial CBCT slice. Top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E. Below is the CT image (labeled C) with numbered callouts: 1. Nasal septum, 2. Nasolacrimal duct, 3. Maxillary sinus, 4. Nasal turbinate, 5. Zygomatic process of maxilla, 6. Zygomaxillary suture, 7. Zygomatic arch, 8. Pterygopalatine fossa, 9. Greater wing of sphenoid bone, 10. Carotid canal, 11. Petrous portion of temporal bone, 12. Internal auditory canal, 13. Infraorbital canal, 14. Lateral wall of maxillary sinus, 15. Pterygomaxillary fissure, 16. Foramen ovale, 17. Foramen spinosum, 18. Glenoid fossa, 19. Mandibular condyle, 20. Carotid canal, 21. Infraorbital foramen, 22. Nasal cavity, 23. Pterygoid plates, 24. Nasopharyngeal airway, 25. Occipital bone, 26. Jugular foramen, 27. Medial wall of maxillary sinus, 28. Coronoid process, 29. Pharyngeal wall, 30. External auditory meatus, 31. Mastoid process, 32. Anterior nasal spine, 33. Nasopalatine canal, 34. Hard palate, 35. Intermaxillary suture, 36. Ramus of mandible, 37. Anterior arch of atlas (C1), 38. Foramen magnum. Anatomical diagram and corresponding axial CBCT slice. Top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E. Below is the CT image (labeled D) with numbered callouts: 1. Incisive foramen, 2. Tongue, 3. Maxillary tuberosity, 4. Soft palate, 5. Oropharyngeal airway, 6. Styloid process, 7. Anterior arch of atlas (C1), 8. Odontoid process of C2, 9. Ramus of mandible, 10. Mandibular foramen, 11. Inferior body of C2, 12. Transverse foramen, 13. Lamina of C2, 14. Mandibular symphysis, 15. Genial tubercles, 16. Mental foramen, 17. Epiglottis, 18. Body of hyoid bone, 19. Greater cornu of hyoid bone, 20. C2-C3 neural foramen, 21. Superior articular process of C3, 22. Inferior articular process of C2. Anatomical diagram and corresponding axial CBCT slice. Top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E. Below is the CT image (labeled A) with numbered callouts: 1. Frontal sinus, 2. Frontal bone, 3. Anterior cranial fossa, 4. Squamous portion of temporal bone, 5. Crista galli, 6. Orbit, 7. Greater wing of sphenoid bone, 8. Nasal bone, 9. Anterior ethmoid air cells, 10. Perpendicular plate of ethmoid bone, 11. Posterior ethmoid air cells, 12. Optic canal, 13. Superior orbital fissure, 14. Nasal process of maxillary bone, 15. Uncinate process, 16. Sphenethmoid recess, 17. Sphenoid sinus, 18. Floor of sella turcica, 19. Nasolacrimal duct, 20. Superior turbinate, 21. Inferior orbital fissure, 22. Middle cranial fossa. Anatomical diagram and corresponding axial CBCT slice. Top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E. Below is the CT image (labeled A) with numbered callouts: 1. Nasal septum, 2. Nasolacrimal duct, 3. Maxillary sinus, 4. Nasal turbinate, 5. Zygomatic process of maxilla, 6. Zygomaxillary suture, 7. Zygomatic arch, 8. Pterygopalatine fossa, 9. Greater wing of sphenoid bone, 10. Carotid canal, 11. Petrous portion of temporal bone, 12. Internal auditory canal, 13. Infraorbital canal, 14. Lateral wall of maxillary sinus, 15. Pterygomaxillary fissure, 16. Foramen ovale, 17. Foramen spinosum, 18. Glenoid fossa, 19. Mandibular condyle, 20. Carotid canal, 21. Infraorbital foramen, 22. Nasal cavity, 23. Pterygoid plates, 24. Nasopharyngeal airway, 25. Occipital bone, 26. Jugular foramen, 27. Medial wall of maxillary sinus, 28. Coronoid process, 29. Pharyngeal wall, 30. External auditory meatus, 31. Mastoid process, 32. Anterior nasal spine, 33. Nasopalatine canal, 34. Hard palate, 35. Intermaxillary suture, 36. Ramus of mandible, 37. Anterior arch of atlas (C1), 38. Foramen magnum. Anatomical diagram and corresponding axial CBCT slice. Top portion shows a lateral skull schematic with horizontal lines labeled A, B, C, D, E. Below is the CT image (labeled A) with numbered callouts: 1. Incisive foramen, 2. Tongue, 3. Maxillary tuberosity, 4. Soft palate, 5. Oropharyngeal airway, 6. Styloid process, 7. Anterior arch of atlas (C1), 8. Odontoid process of C2, 9. Ramus of mandible, 10. Mandibular foramen, 11. Inferior body of C2, 12. Transverse foramen, 13. Lamina of C2, 14. Mandibular symphysis, 15. Genial tubercles, 16. Mental foramen, 17. Epiglottis, 18. Body of hyoid bone, 19. Greater cornu of hyoid bone, 20. C2-C3 neural foramen, 21. Superior articular process of C3, 22. Inferior articular process of C2. # Coronal CBCT Anatomy <table> <tr> <th colspan="3">Anatomy Key 1</th> <th colspan="3">Anatomy Key 2</th> <th colspan="3">Anatomy Key 3</th> </tr> <tr> <td>1. Frontal bone</td> <td>10. Maxillary sinus</td> <td>19. Uncinate process</td> <td>1. Ethmoid air cells</td> <td>11. Coronoid process of mandible</td> <td>21. Optic canal</td> <td>1. Glenoid fossa</td> <td>11. External auditory meatus</td> <td>21. Body of C3</td> </tr> <tr> <td>2. Frontal sinus</td> <td>11. Nasopalatine canal</td> <td>20. Infraorbital ethmoid air cells (Haller cells)</td> <td>2. Superior nasal turbinate</td> <td>12. Maxillary tuberosity</td> <td>22. Foramen rotundum</td> <td>2. Mandibular condyle</td> <td>12. Odontoid process of C2</td> <td>22. Foramen magnum</td> </tr> <tr> <td>3. Nasal bone</td> <td>12. Incisive foramen</td> <td>21. Ostium of maxillary sinus</td> <td>3. Middle nasal turbinate</td> <td>13. Inferior alveolar canal</td> <td>23. Pterygoid (vidian) canal</td> <td>3. Foramen spinosum</td> <td>13. Ossicles of ear</td> <td>23. Mastoid process</td> </tr> <tr> <td>4. Maxillary bone</td> <td>13. Orbit</td> <td>22. Infundibulum</td> <td>4. Zygomatic arch</td> <td>14. Sphenoid sinus</td> <td>24. Nasopharyngeal airway</td> <td>4. Basiocciput</td> <td>14. Occipital condyles</td> <td>24. Occipito-mastoid suture</td> </tr> <tr> <td>5. Nasal septum</td> <td>14. Middle nasal turbinate</td> <td>23. Hiatus semilunaris</td> <td>5. Maxillary sinus</td> <td>15. Pterygopalatine fossa</td> <td>25. Squamous temporal bone</td> <td>5. Carotid canal</td> <td>15. Lateral mass of C1</td> <td></td> </tr> <tr> <td>6. Inferior nasal turbinate</td> <td>15. Zygomatic process of the maxilla</td> <td>24. Frontal recess</td> <td>6. Inferior nasal turbinate</td> <td>16. Lateral pterygoid plate</td> <td>26. Zygomatic process of temporal bone</td> <td>6. Petro-occipital suture</td> <td>16. Mastoid air cells</td> <td></td> </tr> <tr> <td>7. Ethmoid air cells</td> <td>16. Mandible</td> <td>25. Ethmoid bulla</td> <td>7. Hard palate (floor of nasal cavity)</td> <td>17. Medial pterygoid plate</td> <td>27. Sphenosquamousal suture</td> <td>7. Styloid process</td> <td>17. Internal auditory meatus</td> <td></td> </tr> <tr> <td>8. Nasolacrimal duct</td> <td>17. Crista galli of ethmoid bone</td> <td>26. Inferior meatus</td> <td>8. Sphenoid bone</td> <td>18. Mandibular ramus</td> <td>28. Foramen ovale</td> <td>8. Oropharyngeal airway</td> <td>18. Jugular foramen</td> <td></td> </tr> <tr> <td>9. Infraorbital canal</td> <td>18. Fronto-zygomatic suture</td> <td></td> <td>9. Inferior orbital fissure</td> <td>19. Floor of sella turcica</td> <td>29. Palatine tonsils</td> <td>9. Epiglottis</td> <td>19. Jugular bulb</td> <td></td> </tr> <tr> <td></td> <td></td> <td></td> <td>10. Perpendicular plate of ethmoid bone</td> <td>20. Anterior clinoid process</td> <td>30. Hyoid bone</td> <td>10. Semicircular canal</td> <td>20. Body of C2</td> <td></td> </tr> </table>              #### Anatomy Key 1 1. Frontal bone 2. Frontal sinus 3. Nasal bone 4. Maxillary bone 5. Nasal septum 6. Inferior nasal turbinate 7. Ethmoid air cells 8. Nasolacrimal duct 9. Infraorbital canal 10. Maxillary sinus 11. Nasopalatine canal 12. Incisive foramen 13. Orbit 14. Middle nasal turbinate 15. Zygomatic process of the maxilla 16. Mandible 17. Crista galli of ethmoid bone 18. Fronto-zygomatic suture 19. Uncinate process 20. Infraorbital ethmoid air cells (Haller cells) 21. Ostium of maxillary sinus 22. Infundibulum 23. Hiatus semilunaris 24. Frontal recess 25. Ethmoid bulla 26. Inferior meatus #### Anatomy Key 2 1. Ethmoid air cells 2. Superior nasal turbinate 3. Middle nasal turbinate 4. Zygomatic arch 5. Maxillary sinus 6. Inferior nasal turbinate 7. Hard palate (floor of nasal cavity) 8. Sphenoid bone 9. Inferior orbital fissure 10. Perpendicular plate of ethmoid bone 11. Coronoid process of mandible 12. Maxillary tuberosity 13. Inferior alveolar canal 14. Sphenoid sinus 15. Pterygopalatine fossa 16. Lateral pterygoid plate 17. Medial pterygoid plate 18. Mandibular ramus 19. Floor of sella turcica 20. Anterior clinoid process 21. Optic canal 22. Foramen rotundum 23. Pterygoid (vidian) canal 24. Nasopharyngeal airway 25. Squamous temporal bone 26. Zygomatic process of temporal bone 27. Sphenosquamousal suture 28. Foramen ovale 29. Palatine tonsils 30. Hyoid bone #### Anatomy Key 3 1. Glenoid fossa 2. Mandibular condyle 3. Foramen spinosum 4. Basiocciput 5. Carotid canal 6. Petro-occipital suture 7. Styloid process 8. Oropharyngeal airway 9. Epiglottis 10. Semicircular canal 11. External auditory meatus 12. Odontoid process of C2 13. Ossicles of ear 14. Occipital condyles 15. Lateral mass of C1 16. Mastoid air cells 17. Internal auditory meatus 18. Jugular foramen 19. Jugular bulb 20. Body of C2 21. Body of C3 22. Foramen magnum 23. Mastoid process 24. Occipito-mastoid suture Lateral anatomical diagram of a skull with vertical blue lines labeled A, B, C, D, E indicating coronal slice planes. Lines are marked with letters (EC, A, E, C, A, D, B) at the top and bottom. Coronal CBCT radiograph of the mid-face showing nasal cavity, maxillary sinuses, and orbits. Yellow numbered callouts point to various anatomical structures including frontal bone, ethmoid air cells, and maxillary sinus. Lateral anatomical diagram of a skull with vertical blue lines labeled A, B, C, D, E indicating coronal slice planes. Lines are marked with letters (E, C, A, D, B) at the top and bottom. Coronal CBCT radiograph of the cranio-cervical junction showing mandibular condyles, mastoid air cells, and cervical spine. Yellow numbered callouts point to structures like glenoid fossa, external auditory meatus, and odontoid process. Lateral anatomical diagram of a skull with vertical blue lines labeled A, B, C, D, E indicating coronal slice planes. Lines are marked with letters (E, C, A, D, B) at the top and bottom. Coronal CBCT radiograph of the facial skeleton focusing on nasal cavity and maxillary sinus region. Yellow numbered callouts identify frontal bone, frontal sinus, nasal bone, and orbit. Coronal CBCT radiograph of the facial skeleton focusing on nasal cavity and maxillary sinus region. Yellow numbered callouts identify superior nasal turbinate, middle nasal turbinate, inferior nasal turbinate, and hard palate. Coronal CBCT radiograph of the temporal bone and mandible region. Yellow numbered callouts identify zygomatic arch, sphenoid bone, mandibular ramus, and coronoid process of mandible. Coronal CBCT radiograph of the cranial base and upper cervical spine. Yellow numbered callouts identify petro-occipital suture, styloid process, occipital condyles, and body of C3. Coronal CBCT radiograph of the cranial base and upper cervical spine. Yellow numbered callouts identify carotid canal, foramen spinosum, jugular foramen, and occipito-mastoid suture. Anatomy Key 1: Table listing anatomical structures identified in the first column set of figures (1-18). Includes Frontal bone, Maxillary sinus, Nasolacrimal duct, Inferior orbital fissure, etc. Anatomy Key 2: Table listing anatomical structures identified in the second column set of figures (1-20). Includes Ethmoid air cells, Superior nasal turbinate, Zygomatic arch, Sphenoid bone, etc. Anatomy Key 3: Table listing anatomical structures identified in the third column set of figures (1-30). Includes Glenoid fossa, Mandibular condyle, External auditory meatus, Foramen magnum, Body of C3, etc. Sagittal CBCT Anatomy White and Pharoah's ORAL RADIOLOGY 8th EDITION Principles and Interpretation Sanjay M. Mallya Ernest W.N. Lam ELSEVIER 1. Frontal bone 2. Frontal sinus 3. Nasal bone 4. Sella turcica 5. Sphenoid sinus 6. Clivus 7. Anterior nasal spine 8. Nasopalatine canal 9. Hard palate 10. Incisive foramen 11. Mandibular symphysis 12. Nasopharyngeal airway 13. Oropharyngeal airway 14. Epiglottis 15. Hyoid bone 16. Hypopharynx 17. Anterior arch of C1 18. Odontoid process of C2 19. Posterior arch of C1 20. Spinous process of C2 21. Body of C3 22. Body of C4 23. Ethmoid air cells 24. Hiatus semilunaris 25. Middle turbinate 26. Inferior turbinate 27. Soft palate 28. Base of tongue 29. Vallecula 30. Orbit 31. Floor of orbit/Roof of maxillary sinus 32. Maxillary sinus 33. Floor of maxillary sinus 34. Pterygoplatine fossa 35. Occipital condyle 36. Ossicle of middle ear 37. Mastoid process 38. Articular eminence 39. Mandibular condyle       1. Frontal bone 2. Frontal sinus 3. Nasal bone 4. Sella turcica 5. Sphenoid sinus 6. Clivus 7. Anterior nasal spine 8. Nasopalatine canal 9. Hard palate 10. Incisive foramen 11. Mandibular symphysis 12. Nasopharyngeal airway 13. Oropharyngeal airway 14. Epiglottis 15. Hyoid bone 16. Hypopharynx 17. Anterior arch of C1 18. Odontoid process of C2 19. Posterior arch of C1 20. Spinous process of C2 21. Body of C3 22. Body of C4 23. Ethmoid air cells 24. Hiatus semilunaris 25. Middle turbinate 26. Inferior turbinate 27. Soft palate 28. Base of tongue 29. Vallecula 30. Orbit 31. Floor of orbit / Roof of maxillary sinus 32. Maxillary sinus 33. Floor of maxillary sinus 34. Pterygopalatine fossa 35. Occipital condyle 36. Ossicle of middle ear 37. Mastoid process 38. Articular eminence 39. Mandibular condyle Schematic diagram of a human skull showing vertical sagittal plane lines labeled A through E. These lines indicate the specific sections for the CBCT scans shown in the adjacent panels. Sagittal CBCT slice (labeled A) corresponding to the anterior-most section. Features yellow callouts pointing to anatomical structures including the frontal bone/sinus, nasal cavity, sphenoid sinus, and cervical spine. Sagittal CBCT slice (labeled C) corresponding to a mid-sagittal section. Features yellow callouts pointing to the ethmoid air cells, maxillary sinus, soft palate, tongue base, and hyoid bone. Sagittal CBCT slice (labeled E) corresponding to the posterior-most section. Features yellow callouts pointing to the middle ear ossicles, mastoid process, and mandibular condyle. Photograph of the cover of the book 'White and Pharoah's Oral Radiology', which serves as the source reference for the anatomy presented on the slide. A three-column legend table providing verbatim labels for numbers 1-39 found in the figure panels. It lists anatomical terms such as Frontal bone, Hyoid bone, Orbit, and Mandibular condyle. # CBCT Additional Display **IE. Secondary Reconstruction** - **Special algorithm required** 1. **Reconstructed panoramic / curved oblique view** 2. **Volume / 3D rendering** 3. **Transaxial / Cross-sectional** Standard (**axial plane**)  CBCT Additional Display ### Secondary Reconstruction - Special algorithm required 1. **Reconstructed panoramic / curved oblique view** 2. **Volume / 3D rendering** 3. **Transaxial / Cross-sectional** **Standard (axial plane)** Medical imaging composite figure demonstrating CBCT Secondary Reconstruction. The layout consists of multiple panels showing dental anatomy: top-left shows a standard axial cross-section; top-right displays a reconstructed panoramic/curved oblique view of the teeth; bottom-left presents a series of transaxial/cross-sectional slices through the jawbone; and bottom-right features a volume/3D rendering of the skull in an orange-yellow color map. Red arrows connect these specific visual examples to their corresponding labels on the left text list. Other Additional Displays - **TMJ mode** - **Mandibular Canal Tracing** - **Implant placement simulator** - **Airway mode** A: Cone beam CT slice     ### Other Additional Displays - **TMJ mode** - **Mandibular Canal Tracing** - **Implant placement simulator** - **Airway mode** A: Cone beam CT slice Clinical radiograph showing a sagittal view of the temporomandibular joint (TMJ) and surrounding craniofacial anatomy. The image displays the condyle within the glenoid fossa with visible trabecular bone patterns in the mandible and maxilla. Medical imaging display demonstrating Mandibular Canal Tracing. Two panels show cross-sectional views of the jawbone where a bright green line traces the inferior alveolar canal along the root tips of the teeth to avoid nerve damage during procedures. Digital visualization of an Implant placement simulator. Multiple panels display 3D rendered models of dental implants (colored pink/green) positioned within the patient's jawbone structure, overlaid on cone-beam CT data for surgical planning. Sagittal anatomical diagram illustrating Airway mode. It shows a side profile of a human skull with a multi-colored volume rendering (yellow/red/orange gradient) representing the airway passage extending from the nasal cavity through the pharynx to the larynx. # Limitations & Artefacts ## Poor soft tissue contrast - Poor soft tissue contrast - Noise - Patient related - Movement - Tremor - Child - Restorations - High density restorations eg. amalgams, crowns, implants, etc. - Under-sampling - Partial volume averaging - Beam hardening - Cone beam effect - Detector related - Ring artefact - Dead pixel ### Restoration artefact ### Movement artefact   #### Poor soft tissue contrast - Noise - Patient related - Movement - Tremor - Child - Restorations - High density restorations eg. amalgams, crowns, implants, etc. - Under-sampling - Partial volume averaging - Beam hardening - Cone beam effect - Detector related - Ring artefact - Dead pixel #### Restoration artefact #### Movement artefact Clinical radiograph demonstrating a restoration artefact. The image shows a dental restoration (likely an amalgam or crown) causing significant streak artifacts and beam hardening effects that obscure surrounding anatomical structures. Clinical radiograph demonstrating a movement artefact. The image shows severe blurring and distortion of anatomical structures, consistent with patient motion during the scan acquisition. Most pronounced artefacts: - Patient movement artefact - CBCT takes up to 30 seconds to scan - Restoration artefacts (or just dense object artefacts) → - Cupping artefact (shape distortion) - Scatter/Streaking (white lines) - Beam hardening (black lines)  #### Most Pronounced Artefacts - Patient movement artefact - CBCT takes up to 30 seconds to scan - Restoration artefacts (or just dense object artefacts) - Cupping artefact (shape distortion) - Scatter/Streaking (white lines) - Beam hardening (black lines) Clinical radiograph (CBCT scan) of the mandible demonstrating dental restoration artifacts. The image shows bright white crowns with associated dark streaks and lines labeled 'Cupping artifact', 'Scatter', and 'Beam hardening' to illustrate shape distortion and dense object effects. # CBCT Imaging – Medicolegal * “Dental practitioners using CBCT must be adequately trained in the safe use of CBCT and should abide by the Code of Practice and Safety Guide for Radiation Protection in Dentistry (2005) produced and published by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).” – Dental Board of Australia * License required to operate CBCT units * Four (4) Licensing Courses Available in Australia: [http://www.radiologicalcouncil.wa.gov.au/Pages/FAQ/Dentists.html](http://www.radiologicalcouncil.wa.gov.au/Pages/FAQ/Dentists.html) * **Medicolegally, WA dentists MUST** refer their CBCT to registered OMF or medical radiologist for radiology reports * Dentists in other Australian States and Territories are able to write their own radiology reports with adequate training - “Dental practitioners using CBCT must be adequately trained in the safe use of CBCT and should abide by the Code of Practice and Safety Guide for Radiation Protection in Dentistry (2005) produced and published by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).” – Dental Board of Australia - License required to operate CBCT units - Four (4) Licensing Courses Available in Australia: [http://www.radiologicalcouncil.wa.gov.au/Pages/FAQ/Dentists.html](http://www.radiologicalcouncil.wa.gov.au/Pages/FAQ/Dentists.html) - **Medicolegally, WA dentists MUST** refer their CBCT to registered OMF or medical radiologist for radiology reports - Dentists in other Australian States and Territories are able to write their own radiology reports with adequate training **References** * Dental board of Australia * Oracle radiology — principles and interpretation 8th ed * Essentials of dental radiography and radiology 5th edition by Whaites, Eric; Drage, Nicholas Churchill Livingstone. 2013 **White and Pharoah's** **ORAL** **RADIOLOGY** Principles and Interpretation **8th** **EDITION** Sanjay M. **Mallya** Ernest W. N. **Lam** ELSEVIER - Dental board of Australia - Oracle radiology — principles and interpretation 8th ed - Essentials of dental radiography and radiology 5th edition by Whaites, Eric; Drage, Nicholas Churchill Livingstone. 2013 - White and Pharoah's Oral Radiology: Principles and Interpretation, 8th edition. Sanjay M. Mallya, Ernest W. N. Lam. Elsevier. 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