1. Principles of Cone Beam Volumetric Tomography

2. Planmeca ProMax 3D Models
Planmeca ProMax 3D family offers a solution for the most demanding imaging needs, producing various imaging sizes with one concept – an ideal imaging size for different maxillofacial applications.

3. Extended applications
Unique new imaging capabilities for:
Implant planning
Oral surgery
Impacted teeth
3rd molar extractions
Occlusion analysis
TMJ analysis
Periodontics
Airway studies
Emerging new diagnostic applications

4. 3D technology CBCT - Cone Beam Computed Tomography
CBVT - Cone Beam Volumetric Tomography
DVT – Digital Volume Tomography
A technological advance from traditional ‘CAT Scan’, ‘medical CT’ or ‘fan beam CT’ 4

5. Medical CT

6. Medical CT vs CBVT Movement of translation and axis of rotation
Flat panel
detector
axis of rotation
Line detector
object
object
X-ray source
X-ray source

7. CBCT volume capture 7

8. CBCT volume capture Z Y X

9. Medical CT vs. CBVT Medical CT:
Slices are acquired then reconstructed to create the volume 9

10. Medical CT vs. CBVT CBCT:
The volume is acquired then slices are reconstructed from the volume 10

11. ProMax 3D technology
Stroboscopic effect, images taken using short X-ray pulses during the scan
300/450 images taken during the scan
Cumulative exposure time sec for 18 sec scan
Enhanced clarity of the images
Reduced radiation dose

12. ProMax 3D Max & Mid Scanning
Symmetric scanning
C-arm rotates
Magnification 1.8x
Scan angle 200 deg
300 frames
Max. volume Ø100 x 130 mm
Asymmetric off-set scanning
Elbow arm rotates
Magnification 1.44x
Scan angle 360 deg
450 frames
Max. volume Ø230 x 160 mm

13. Asymmetric off-set scanning
SCARA!
Sensor shift changes the acquisition geometry and reduces the final image quality
The shift of whole c-arm remains the acquisition geometry constant and produces better final image

14. Back projection – basic images

15. Back projection

16. ProMax 3D Technology 3D image volume is a cylinder
Cylinder consists of more than 120 million voxels
Voxel size x 0.1 x 0.1 mm, 0.2 x 0.2 x 0.2 mm, 0.4 x 0.4 x 0.4 mm or 0.6 x 0.6 x 0.6 mm

17. Isotropic voxel CBVT has always an isotropic voxel
The reconstruction can produce any size of voxel
The voxel is always perfect cube
The measurements are exact
Voxel size is typically 0.1 – 0.5 mm
CT has an anisotropic voxel
The voxel is always a “brick”
The pitch (= distance between spiral rounds = layer thickness) varies and causes distortion in the 3D measurements.
The layer thickness is typically 0.5 – 0.8 mm

18. Pulsed X-ray
Pulsed X-ray produces sharp images with less dose. 18

19. 3D Technology –Flat Panel
Planmeca ProMax 3D flat panel imaging chain
Conventional imaging chain with Image Intensifier
X-ray Tube – Patient – Flat Panel - Digital Image
X-ray Tube – Patient – Image Intensifier – TV Camera – Digital Image
Modern Flat Panel Technology for maximum performance 19

20. Image intensifier

21. 3D Technology – Flat Panel
Image intensifier has both distortion and brightness non-uniformity which is absent from the flat panel detector
Image intensifier needs periodical maintenance. It has limited life span 3-6 years.
It is sensitive to magnetic or electrical fields.
It is over 60 years old technology. 21

22. 3D technology – Tube Current Modulation
Different attenuation properties across and along the patient's head
Tube current (mAs) can be dynamically adjusted
Reduces patient dose and improves image quality
more
less 22

23. Comparison Planmeca ProMax 3D s ProMax 3D ProMax 3D Mid ProMax 3D Max
Voxel size
100 / 200 µm *
100 / 200 / 400 µm
100 / 200 / 400 / 600 µm
Max. 3D volume (diam. x height )
Ø50 x 80 mm
Ø80 x 80 mm
Ø160 x 90 mm
Ø230 x 160 mm
Max. 3D volume with
stitching, (diam. x height)
Ø90 x 130 mm
Ø150 x 130 mm
Ø160 x 160 mm
Ø230 x 260 mm
Stitching, vertical
Yes
Stitching, horizontal No
SmartPan imaging
Dimax Panoramic imaging
Optional
Dimax Cephalostat
Motorised patient support
for vertical movement

24. CBCT vs. Medical CT Cone Beam Imaging is: Faster Smaller
Safer (lower dose)
Less expensive
More convenient
Dentally specific
Higher resolution
Better image quality

25. WHAT ARE THE DOSES?

26. Radiation dose
International Commision on Radiological Protection, Standards for absorbed dose from and 2007 26

27. Radiation dose Dig. Pan ca 7 µSv Medical CT 1200-3300 µSv FMS 90 uSv
Dr Sharon Brooks, O of Michigan, ICRP 1990
Dig. Pan 6,7 µSv
FMS 84 uSv
Dr Stuart White 1992, ICRP 1990
Typical panoramic dose 24.5 µSv
Dr Ludlow, ICRP 2007
Medical CT µSv
Dr Stuart White, UCLA 27

28. Radiation dose Radiation dose of CBCT 20- 250 µSv
The estimated effective patient dose, Planmeca ProMax 3D software version , Dr. Mika Kortesniemi:
IMAGING PROTOCOL
High and Normal
Resolution modes
Low Dose mode
IMAGING OBJECT
Left 3rd molar
FOV [d cm x h cm]
8 x 8
TUBE VOLTAGE [kV] 84
TUBE CURRENT [mA] 12 8
EXPOSURETIME [s]
2.8
CURRENT TIME PRODUCT [mAs]
144
22.4
CURRENT TIME PROFILE [MIN(mAs) / MAX(mAs)]
1.0
0.3
Effective dose [mSv]
(ICRP 1990)
0.122
0.021
(ICRP 2007)
0.252
0.045
Radiation dose of CBCT µSv
Same level as 2-10 panoramic images
Same level as full mouth series with film
Essentially lower than medical CT 28

29. Dose – Radon, background, smoking
US Study:
Average yearly dose of 2070 µSv from radon
Average yearly dose of 320 µSv from smoking
Average yearly dose of 4000 µSv from background radiation in Denmark 29

30. Dose – Flight 30

31. Dose – Risks
Modality: Risk of fatal cancer (per million):
Intraoral 0,02 – 0,6
Occlusal 0,4
Panoramic 0,21 – 1,9
Ceph 0,34
CT mandible 18,2 – 88
CT maxilla 8 – 242
Age:
<10 *3
10-20 *2
20-30 *1,5
30-50 *0,5
50-80 *0,3
80+ negligible
ec.europa.eu/energy/nuclear/radioprotection/publication/doc/136_en.pdf 31

32. The End More information: Erkki Hiltunen Product Manager, X-rays
tel:
Mark Niemi
tel:
More information:
Osku Sundqvist
Product Manager, Software
tel:
4/2011 32