User Guide for Dental and Maxillofacial Cone Beam Computed Tomography (CBCT) Poster No.: C-0756 Congress: ECR 2014 Type: Educational Exhibit Authors: J. Ukkonen, J. Asp; Helsinki/FI Keywords: Education and training, Computer Applications-3D, Cone beam CT, Head and neck DOI: 10.1594/ecr2014/C-0756 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 18
Learning objectives The purpose of this project is to give practical information of dental and maxillofacial CBCT imaging. The user guide is a part of evidence based quality assurance in digital dental imaging (EQD) -project. The User Guide for Dental and Maxillofacial CBCT includes basic information about CBCT, detailed pictures of the device, indications for examination, information about preparing patient and the device, patient positioning for lower wisdom tooth examination and information about imaging and radiation. The User Guide's aim is to help and introduce dental and maxillofacial CBCT for professionals who are beginning to work with the device. Page 2 of 18
Background EQD-project: The EQD-project aims to produce an educational package for evidence based digital imaging and quality assurance for dental X-RAY equipment and viewing conditions. With modern technology it is possible to get lower radiation doses with the same image quality, but there is also possibility for dose increase because it is easy and quick to take more x-rays. With this in mind, the user guide gives instructions for imaging and patient positioning so that image quality is adequate and patient's radiation dose is as low as possible. About Cone Beam Computed Tomography (CBCT) -device: The CBCT device is well suitable for imaging small objects e.g. teeth. The device uses ionizing radiation. The images are 3-dimensional and consist of hundreds of cross-sectional images. Components of CBCT device: Page 3 of 18
Fig. 4: Components of CBCT device References: J. Ukkonen, J. Asp; Helsinki/FI 1. 2. 3. 4. 5. 6. 7. Tube head assembly (radiation production) 3D-sensor (radiation receiver) Control panel Patient positioning controls Head support Patient handles Cephalometric imaging Good to know about CBCT examination: CBCT is an additional examination for panoramic and intra-oral imaging. Radiographers can perform the examination independently. Healthcare professionals who have received continuing education can perform the examination under physicians surveillance (STUK ST 3.1). CBCT is not well adjusted for imaging soft tissue related problems. Indications: Page 4 of 18
(STUK) CBCT examination is primarily suitable for planning of implant surgery clarifying the relation between lower wisdom tooth and mandibular canal when suspecting the possibility of nerve damage imaging maxillofacial cysts (in case of tumor imaging it is recommended to use e.g. conventional CT-examination) imaging dental and alveolar bone fractures clarifying the kind of pain that conventional imaging has not been able to resolve. Radiation and CBCT: Patient gets significantly larger amounth of radiation in CBCT than in intra-oral or panorama examinations. Dental panorama examination is equivalent to two days of natural background radiation. CBCT causes 2-40 times more radiation compared to panorama examination. The specialist in charge of procedures estimates the justification for examination. Physician writes up imaging instructions for healthcare professionals, who have received continuing education. The instructions include: The area of imaging The size of FOV (field of view) Imaging values Resolution All these parameters affect on the patient's radiation dose When considering patient's radiation dose the image should be diagnostic. Page 5 of 18
Images for this section: Fig. 2: A sagittal image of molars taken with CBCT device J. Ukkonen, J. Asp; Helsinki/FI Page 6 of 18
Fig. 3: A 3D reconstruction of images taken with CBCT device J. Ukkonen, J. Asp; Helsinki/FI Page 7 of 18
Findings and procedure details Preparation of examination: The referral clarifies the object of imaging. In case the object is a tooth, tooth's number is clarified in the referral. Fig. 5: Teeth numbering References: J. Ukkonen, J. Asp; Helsinki/FI Page 8 of 18
Control Panel: From the control panel user selects area/object of imaging imaging values (e.g. wisdom tooth 90kv 8mAs) resolution Fig. 6: Control panel References: J. Ukkonen, J. Asp; Helsinki/FI Patient positioning: Page 9 of 18
lower wisdom tooth examination Fig. 7: Interviewing the patient References: J. Ukkonen, J. Asp; Helsinki/FI The patient is asked to take off all removeable objects from the head and neck area (e.g. jewellery) It should be confirmed that female patients are not pregnant. Page 10 of 18
Fig. 8: Preparing the patient References: J. Ukkonen, J. Asp; Helsinki/FI Lead apron can be used in the examination to minimize radiation exposure. It is not recommended to use lead apron on patients with broad shoulders because it can cause artifacts to the image. Page 11 of 18
Fig. 9: Positioning the patient References: J. Ukkonen, J. Asp; Helsinki/FI The patient sits straight and places hands on the handles. Height of the device is adjusted so that patient's chin sits straight: the chin should not lean too much forward or backward. Patient is adviced to bite back teeth loosely together. Page 12 of 18
Fig. 10: Positioning with the help of lasers 1 and 2 References: J. Ukkonen, J. Asp; Helsinki/FI The area of imaging is positioned with the help of laser lights: 1. 2. 3. Central sagittal light is lined straight in the middle of the face (between front teeth). Medial layer light is positioned on the canine tooth. Targeting laser is placed on the tooth at issue. Location of the lower wisdom tooth is measured from jawbone. Page 13 of 18
Fig. 11: Positioning with the help of laser 3 References: J. Ukkonen, J. Asp; Helsinki/FI Field of view begins from the level of jaw support, so the jaw should be placed as horisontally as possible. Advice: From an old panorama picture you can measure how many fingers the distance is between the tooth and the jawbone. Remember: Make sure that patient can stay in the same position and understands the importance of staying still. Patient must not swallow during imaging. Page 14 of 18
If patient moves during imaging, examination may have to be repeated (in which case the radiation dose is doubled). Imaging: Fig. 12: Imaging References: J. Ukkonen, J. Asp; Helsinki/FI The first image is scout picture which shows the location of the object. If the issued object is not in the center of scout picture, targeting laser may be used at this point to change the area of imaging. It is important to have the object right at the center of the area of imaging. Imaging may begin when the object is definitely in right position. Page 15 of 18
Conclusion The Dental CBCT device is relatively new and it will probably be used more in the future. Because different healthcare professionals e.g. radiographers and dental hygienists are going to use the device, it is important to make the device known and give information about working with radiation. Page 16 of 18
Personal information Jenni Ukkonen, Radiography and Radiotherapy student Helsinki Metropolia University of Applied Sciences, Finland Jonna Asp, Radiography and Radiotherapy student Helsinki Metropolia University of Applied Sciences, Finland Page 17 of 18
References 1. 2. 3. 4. 5. Baker EW. Head and Neck Anatomy for Dental Medicine 2010. Miles DA. Atlas of Cone Beam Imaging for Dental Applications 2012. STUK - Radiation and Nuclear Safety Authority, Finland: Regulatory guide 3.1 (2011). Whaites E. Radiography and Radiology for Dental Care Professionals 2008. White SC, Pharoah MJ. Oral Radiology Principles and Interpretation 2008. Page 18 of 18