CAD/CAM Computed Tomography

APPENDIX c CAD/CAM Computed Tomography


The following are the CD-ROM handling requirements for all bone modeling exams sent to Techmedica.

The image data from the exam can be stored using any archiving program and copied onto a new, unused CD-ROM. The raw or scan data should be saved as backup. If the scan is performed on the cone beam volumetric tomography (CBVT) scanner, the formatted image can be copied onto a CD-ROM using an archiving program included with the software native to the scanner.

The CD-ROM must be clearly labeled as follows:

The scout view is filmed with the slice locations posted (every other or every third slice location is posted if the scan interval is small) and the sagittal and coronal arrange cuts through the plastic rod.

Mandible Modeling for a Subperiosteal Implant

CT Scan Protocols Data Transmission Procedure
Patient movement Scanner maintenance check Remove all metal from patient’s head and neck (e.g., jewelry, hairpins).
Anatomic feature Mandible Position the patient with the head as far into the head holder as possible.
Wear gloves.
Patient positioning With the patient lying supine, place the head as far as possible into the coronal head holder so that the mandible is behind the metal in the forward part of the head holder. Place a pillow under the patient’s knees for comfort. Wedge sponges between the head and head holder, if space is available, to prevent patient movement. Strap the chin and forehead. Wet the intraoral jig and shake off excess moisture. Sprinkle the gum areas of the jig with Rigident powder and shake off excess. Insert the jig into the patient’s mouth. Lubrication of the lips with lubricating jelly may be necessary.
Attach the vacuum line to the jib tube and set on the lowest possible setting that still evacuates saliva. If the vacuum “grabs” the tongue, reduce vacuum.
Palpate the inferior border of the anterior body of the mandible and position it parallel to the scan plane. Secure patient’s head in head holder.
Plastic rod location Tape the ⅜ -inch diameter plastic rod to the patient’s face, down the midline, from the end of the nose to past the end of the chin, so that the rod is approximately perpendicular to the scan plane.

Scout view Lateral Scan thickness 1.5 mm Scan interval 1 mm (entire body of mandible)   1.5 mm (rami of mandible) Prospective target Center target half the distance between the mentum and the anterior aspect of the body of the vertebra Calibration file Head Target factor
(GE 8800 scanner) 1.25 (key in all three digits) Field of view
(GE 9800 scanner) 20 cm Algorithm (mA) 0 (bone) (GE 8800 scanner) 320 mA at 2 pulse width, KV = 120 (Note: If fast tube cooling is available, use dynamic scan at 320 mA, 2 pulse width with interscan delay of 7 sec for first 20 slices.) (GE 9800 scanner) 200 mA at 2 sec scan time, KV =120 Raw/scan data save Yes (save for 3 months at your facility. Do not send raw/scan data to Techmedica) First slice location 1.5 mm below inferior border of the body of the mandible.

Jan 5, 2015 | Posted by in Implantology | Comments Off on CAD/CAM Computed Tomography
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