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Int Poster J Dent Oral Med 12 (2010), No. 3     15. Sep. 2010

Int Poster J Dent Oral Med 2010, Vol 12 No 3, Poster 501

Cone-beam computed tomography: Small cone big scoop!

Seeing 3D just like the movies... but without the need of 3D glasses

Language: English
 

Authors:
Dr. Archana R. Shenoy, Dr. Sushma P, Prof. Dr. Ashok Lingappa, Prof. Dr. Sujatha G. P,
Department of Oral Medicine and Radiology, Bapuji Dental College and Hospital Davangere, Karnataka, India

Date/Event/Venue:
December 4th-6th, 2009
XXI National Conference of Indian Academy of Oral Medicine and Radiology 2009
Modern Dental College and Research Centre, Indore, India
 

Introduction

Cone-beam computed tomography (CBCT) is the latest advancement in diagnostic imaging that has begun to emerge as a potentially low dose cross-sectional technique for visualizing bony structures in the maxillofacial region.

CBCT yesterday... today... tomorrow...
Pioneers in X-ray computed tomography: Sir Godfrey Hounsfield and Allan McLeod Cormack
First CT scanner - 1972
First CBCT for angiography - 1982
First CBCT in dentistry - 1998

Advances:
MVCBCT (Mega Voltage CBCT)

Abb 1: Sir Godfrey Hounsfield Abb 2: Allan McLeod Cormack
Abb 3: Mega Voltage CBCT
 
Abb 4: Principle

Conclusions

Principle:
CBCT scanners utilize a 2D detector and cone-shaped source of ionizing radiation allowing for a single rotation of gantry to generate a scan of the entire region of interest.
How does it work?

X-ray generation:
3D X-ray beam with circular collimation → Cone shaped beam

Image detection system:
Image intensifier tube/ charged coupled device combination or flat panel detector arrays

Image reconstruction:
Acquisition of single projection images known as "basis" images and reconstruction using Feldkamp software algorithm

Image display:
Axial, sagittal and coronal planes

Diagnostic value:
1. Dentomaxillofacial imaging
2. Orthodontic planning
3. Periodontal diseases
4. TMJ analysis
5. Cephalometric analysis
6. Jaw pathologies
7. Radiotherapy guidance
8. Implant site assessment
9. Impacted tooth evaluation

Medical applications:
1. Interventional radiography
2. Angiography
3. Mammography
4. Airway assessment

Benefits:
1. Size: reduced
2. Cost: ¼ to 1/5 of conventional CT
3. Rapid scan time: less than 30 seconds
4. Submillimeter resolution: 0.4 mm to as low as 0.125 mm
5. Patient dose reduction: 52-1025 μSv = 4-77 digital panoramic radiographs
6. Interactive analysis: for real-time dimensional assessment and measurements
7. Image artifact: reduced

Limitations:
1. Image noise
2. Poor soft tissue contrast

Abb 5: Dentomaxillofacial imaging Abb 6: Orthodontic planning
Abb 7: Periodontal diseases Abb 8: TMJ analysis
Abb 9: Cephalometric analysis Abb 10: Jaw pathologies
Abb 11: Radiotherapy guidance Abb 12: Implant site assessment
Abb 13: Impacted tooth evaluation
 
Abb 14: CBCT Scanner

Conclusion:

The ability of CBCT to provide images in three dimensions with a high level of detail makes it a very attractive method for many dental applications.
There is no doubt that cone-beam technology will become an important tool in dental and maxillofacial imaging over the coming decades.
 

Literature

  1. White SC, Pharoah MJ. Oral Radiology - principles and interpretation. 6th edn. India: Elsevier; 2009. p.225-243.
  2. Miracle AC, Mukherji SK. Conebeam CT of the head and neck, Part 2: clinical applications. Am J Neuroradiol 2009 Aug;30:1285-92.
  3. Scarfe WC, Farman AG. What is cone-beam CT and how does it work. Dent Clin North Am 2008;52:707-730.
     

Abbreviations

2D - 2 dimensional
CT - Computed tomography
CBCT - Cone-beam computed tomography
 

This Poster was submitted by Dr. Archana R. Shenoy.
 

Correspondence address:
Dr. Archana R. Shenoy
Bapuji Dental College and Hospital
Department of Oral Medicine and Radiology
Davangere - 577 004
Karnataka, India