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Cone Beam CT An alternative approach to extremity imaging? Peter Sharpe Roisin Dobbin-Stacey Chief Executive PET/CT CT Manager

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Page 1: Cone Beam CT An alternative approach to extremity …...What is Cone Beam CT Traditional CT Cone Beam CT A narrow slice of the patient is imaged with a fan-beam of x-rays and multiple

Cone Beam CT

An alternative approach to extremity imaging?

Peter Sharpe Roisin Dobbin-Stacey

Chief Executive PET/CT – CT Manager

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Medical charity

Providing MRI , PET/CT, CBCT & DXR

65,000 patients annually

Research – Fund and participate

Provide - Training & education.

Cobalt – Who are we?

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Objectives – to innovate

First:

1.5T Mobile MRI

High-field Open MRI

Open PET/CT

3.0T Mobile MRI

ISAS accreditation

Wide bore digital mobile MRI

Flow PET/CT technology

Carestream - MyVue & VueMotion.

Cobalt – Who are we?

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Why CBCT for Cobalt?

Good fit – Innovation and research

Good partnership with Carestream

Very positive reviews from a range of international ‘trade sites’

One stop orthopaedic clinics – DXR weight bearing

Research opportunity.

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What is Cone Beam CT Traditional CT

Cone Beam CT

A narrow slice of the patient is imaged

with a fan-beam of x-rays and multiple

rotations; z direction typically has

lower resolution

A large-area flat panel detector images

an extended volume of the patient in a

single rotation; same (isotropic)

resolution in all 3 directions

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What is Cone Beam CT

Single

Source

3 Source

Increases reconstruction volume by ~50%

Reduces “cone beam” artifact

Enables future advanced acquisition

protocols

o Dual energy

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OnSight Extremity CBCT

Designed specifically for imaging of extremities

Hand, wrist, elbow, knee, ankle, foot

Benefits

Weight bearing imaging for knee / foot / ankle

Comfort features - low dose

Improved visualization over 2D or standard 3D imaging

o Isotropic resolution

o Advanced Iterative image reconstruction

o Good soft tissue visualization

o Advanced Scatter and Metal Artifact Reduction

Large field of view – 21cm x 22cm

Compact design and reduced shielding requirements – Low cost

Fraction of MDCT cost

Imaging right at the point of care - faster diagnosis and treatment

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Installation - Requirements

Small system and footprint

Standard ceiling height

Room shielding typically not

required*

*consult local regulations

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Installation

Room pre-installation and post installation

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OnSight Extremity CBCT

Designed to provide the lowest level of patient

and operator exposure

Patient exposure is reduced - compared to

traditional Multi-Detector CT

Only exposes joint under examination

Minimises scattered radiation - integrated lead

curtain and well shielded

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OnSight Extremity CBCT – Bore volume

Large

field of view

Reconstruction volume

Bore opening

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Applications

Motorised movements - auto-positions

for height, tilt and rotation

Stepstool and positioning guides

Patient monitor for imaging status

Patient support handles

Touch-screen monitor - intuitive user

interface

Specific patient chair

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Applications

One stop orthopaedic clinics

DXR weight bearing studies

Demand for MDCT increasing

Ease of access

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Applications

Potential to replace DXR and MDCT

More diagnostic confidence - Rreduction in repeat examinations

Occult and non-displaced fractures

Scaphoid fracture detection and healing evaluation

Non-unions and growth plate fractures in children, follow-up / fusion healing

Impingement (under load)

Evaluation of disease progression, for RA , OA and Gout

Post operative and follow up joint replacement

Design joint replacement

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Initial Experience – Hand & Wrist

• 3D weight-bearing

• Accurate determination of the relative placement and

orientation of the bones while under realistic load

conditions

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Investigational: Not Available for Commercial Sale

• Fracture Trapezium and

distal radius

Hand and Wrist

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Initial Experience – Foot and Ankle

3D weight-bearing

Accurate determination of the relative placement and

orientation of the bones while under realistic load

conditions

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Investigational: Not Available for Commercial Sale

Large Field of View Image the Tripod of the foot

Weight–Bearing 3D Exams - Ankle

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Sc

Weight–Bearing 3D Exams - Ankle

Non weight-bearing Weight-bearing Non weight-bearing Weight-bearing

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Investigational: Not Available for Commercial Sale

? Impingement MRI vs CBCT & DXR

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Investigational: Not Available for Commercial Sale

Impingement

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Investigational: Not Available for Commercial Sale

Ankle MRI vs. CBCT & DXR – Posterior impingement

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Investigational: Not Available for Commercial Sale

Ankle – post surgery ? union

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Investigational: Not Available for Commercial Sale

Trauma – Metal Artifact Reduction

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Initial Experience – Knee

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Investigational: Not Available for Commercial Sale

Knee - OA

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Investigational: Not Available for Commercial Sale

Knee post KR fracture or loose component

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Investigational: Not Available for Commercial Sale

3D surface rendering

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Effective Dose

References:

Assessment of Effective Radiation Dose od An Extremity CBCT, MDCT and Conventional X-Ray for Knee

Using Mosfet Dosimeters – Juha Kivisto et al Department of Physics, University of Helsinki, Finland., 2013

Imaging of the knee

Modality Effective Dose

MDCT 27 - 48µSv.

CBCT 12.6µSv.

DXR (4 view) 6.0µSv.

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Effective Dose

Modality Effective Dose

Chest MDCT ~7000 µSv (1,2)

Head MDCT ~2000 µSv (1)

Extremity MDCT ~30 to 160 µSv depending on anatomy and study details (4)

Chest radiograph ~20 to 100 µSv depending on study details (3)

OnSight CBCT Extremity scan ~5 to 40 µSv depending on anatomy and study details

2D Radiographic study of an extremity ~0.2 to 3 µSv depending on anatomy and study details (3)

1 day natural background exposure ~17 µSv (1)

1 trans-continental flight from NY to LA ~25 µSv (5)

References:

(1) www.epa.gov/radiation/radiation-sources-and-doses

(2) McCollough et.al. “Answers to common questions about the use and safety of

CT scans.” Mayo Clin Proc. (2015) 90(10):1380-92

(3) Huda W. et.al. “Radiation Dosimetry for Extremity Radiographs” Health Physics

(1998) 75(5):492-499

(4) Biswas et.al. “Radiation Exposure from Musculoskeletal Computerized

Tomographic Scans” J. Bone Joint Surg. Am. (2009) 91:1882-9

(5) http://jag.cami.jccbi.gov/cariprofile.asp

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Conclusion

Initial experience positive

User friendly

Adoption rate typical

Higher resolution images than MDCT and DXR*

Lower dose than MDCT

Quicker than MDCT and DXR*

Good patient acceptance - Weight bearing

Metal Artefact Reduction – Works well

Competes with MDCT – Compliments DXR.

*Using Cone Beam CT as a low-does 3D imaging technique for extremities: initial experience in 50 subjects

Skeletal Radiology June 2015 Huang AJ, Chang CY Thomas BJ;

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Future – Research Project

CBCT with MAR - Assessment of total knee replacement

Potential to deliver high image data with quantifiable

measurement of 3D position, fixation and bone density

Replacing 2D radiographs

Post surgery – assess position , exclude any bone damage

Early years – loosening, infection

End of life- loosening, bone loss, fractures in bone or metal

work

Results – better pre-op assessment, possible personalised

prediction of implant survival.

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