Scanner Validation via the SNM Clinical Trials Network Phantom

Program

Paul E. ChristianMolecular Imaging ProgramHuntsman Cancer Institute

University of Utah

Purpose:

Ensure scanner meets certain performance criterion needed for multi-center clinical trials via a clinical simulation phantom exercise.

Scanner Validation Sub-Committee

• PET lesion detectability not consistent across vendors.

• Imaging/processing protocols not consistent between sites.

• SUV measurements not consistent across vendors nor sites.

• PET data submitted to FDA for multi-center drug studies not deemed reliable.

• Goal: Generate measurement tool to validate reliable multi-center PET data

Validate scanner performance

Quality Control

• Dose Calibrator• CT Scanner

– CT checks– Calibration– Inspection

• PET Scanner– Blank scan– Constancy– PET and CT alignment– Record of PMs and calibrations

Scanner Constancy

Courtesy: Paul E. Christian

Commonly Used PET Phantoms

Commercial phantomsIECNEMA NU-2ACRINACRAAPMQIBACROs

NEMA-IEC NU-2 Phantom

68Ge resin filled phantom 270.8 day T1/2

4.6 mCi Bkgd 0.44 Ci/ml

Spheres 1.75 Ci/ml4:1 sphere/background ratioAtten Coeff 0.103 mm2/g at 511keV59+-7 HU

Ten Sites, Three vendors(GE 4-PET/CT, 2-PET; Philips 1-PET/CT; Siemens 3-PET/CT)

Maximum Absolute RC for 3D OSEM Clinic Scans

0

1

5 10 15 20 25 30 35 40

Sphere Diameter (mm)

Ab

solu

te R

eco

very

Co

effi

cie

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(un

itle

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Kinahan, Doot, U Wash.

CTN Oncology Chest Phantom

• Clinical simulator to measure:– Lesion detectability– Lesion quantitation– Image noise / texture

• Fill with F-18 FDG• Precision Filling Technique• Clinical Concentration• Fixed Lesion/Background

Ratio

CTN Oncology Chest Phantom

Repeat studies usinga precision filling

technique with F-18

Paul E. Christian, Keith Bigham, unpublished data 2008

Precision 18F Fillable Phantom

Biograph HiREZ SUVs

0.0

1.0

2.0

3.0

4.0

5 10 15 20 25 30 35 40

Sphere Diameter (mm)

SU

Vb

w g

/ml Biog 1

Biog 2

Biog 3

Biog 4

Biog 5

Biog Average

Imaging Process

• Fill phantom (precise technique)• Performing imaging according

to prescribed protocol • Image after specific time delay• Reconstruction parameters• MD to identify lesions• Submit images for review

• Quantitative measurements (SUVmax and SUVave)• At site• At core lab

Evaluation Criterion:

Clinical Simulation Phantoms

Evaluate: Image performance-Accuracy of dose-Acquisition-Reconstruction/filter-Interpretation

# Lesions detectedLocation of detected lesionsSUV measurements (site)

-Verify SUVs at core lab-Evaluate DICOM images (core lab)

Image quality of PET/CT scanner-Uniformity-Resolution -Contrast-Noise-PET/CT alignment-Lesion detectability-Attenuation correction-Quantitative accuracy

Scanner Quantitative Validation

Assessment:

SUV background accuracyLesion SUV accuracyDICOM transfer validValidation of SUV DICOM

Scanner Validation Progress

- 17 scanners validated to date- 13 sites- 11 more sites have phantoms- 20+ additional sites scheduled

(worldwide expansion)

Scanner Validation

Site Problems

- DICOM image compatibility- Ability to provide quantitative images- Ability to provide accurate SUVs- Scanner operation/calibration- Dose calibrator

2010 Goals:

Testing brain imaging phantom

Scanner Validation Sub-Committee

2010 Goals:

Testing myocardial perfusion imaging phantom

(3 clinical scenarios)

Scanner Validation Sub-Committee

Accomplishments:

1. Development of scanner validation process

2. Implement review and quality assurance testing

3. Provide on-line phantom instructional video

4. Administration of oncology demonstration project

5. Oncology phantom imaging at 40+ sites

6. Development of myocardial perfusion phantom

7. Development of brain phantom

Scanner Validation Sub-Committee

2010 Goals:

1. Streamline phantom qualification program

2. Develop central archive for images

3. Develop process for long term maintenance and administration of phantom site qualification

4. Implement multi-site testing of brain and cardiac phantoms

Scanner Validation Sub-Committee