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National Institute of Standards and Technology

(NIST) Quantitative Imaging Initiatives Stephen Russek

Project Leader: Biomagnetic Imaging Standards, NIST, Boulder, CO

NIST Boulder

NIST Gaithersburg

F2 time standard

Josephson junction

voltage standard

AAPM MO-C-12A-6 July 21, 2014

Outline

1. Role of NIST

2. NIST Medical Imaging Standards: what's new • Ionizing radiation standards (Radiation Physics Division)

CT / PET phantoms

• Optical imaging standards

• Computational standards (Information Technology Lab)

Virtual/ numerical phantoms

3. MRI standards/ phantoms (Electromagnetics Division) • NIST/ISMRM MRI system phantom

• NIST/USCF breast phantom

• NIST/RSNA QIBA isotropic diffusion phantom (Mike Boss

TU-C-12A-8 Tuesday 10:15AM)

NIST’s Role in Quantitative Medical Imaging

Professional

Societies

Universities

Clinical Sites

Pharma

Venders

NIH

FDA

NIST

• Standard reference materials (SRMs)

• Standard reference artifacts (phantoms)

• Enabling traceability

• Establishment of “ground truth”

• Long term monitoring

• Measurement development/ basic

metrology research

• Setting standards, most standards are

consensus

• Phantom mass production

• Moving very fast

We are good at:

Not good at:

NIST is a National Metrology Institute: measurement & standards

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Safety based standards

Evolution of NIST medical imaging standards

1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

NIST radiation

dose standards

Mammography

Quality Standards Act

NIST Metrology

PET/CT & MRI

Imaging as a Biomarker: Standards for

Change Measurements in Therapy

Workshop Summary

September 14-16, 2006,Laurence Clarke

Ram D. Sriram NISTIR 7434

Congressionally

funded NIST

imaging initiatives

Imaging as quantitative

measurement of biomarkers

Patient Protection and

Affordable Care Act

Metrology for Computed Tomography (CT)

• Calorimetry-based dosimetry (MO-E-17A-12)

• SRMs with calibrated attenuation coefficients

• Simple dimensional phantoms

SRM 2088 Density

Standard for Medical

Computed Tomography Heather Chen-Mayer at the

PET/CT scanner with HDPE

phantoms.

Foam lung

mimics

SRM 2087 Dimensional

Standard for Medical

Computed Tomography

Z.H. Levine

Brian Zimmerman

sta

ndard

s

sta

ndard

s

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Brian Zimmerman

PET Phantoms Brian Zimmerman

• Monitor scanner performance during clinical trials

• Comparison across scanners and clinical sites

• Accuracy of reconstruction and

scatter/attenuation corrections

Standard uncertainty on activity ~ 1 % Compatible with Jaczszak or ACR IQ phantoms

68Ge in epoxy cylinders

Optical coherence tomography: Near-IR 3d

imaging technique that collects scattered light that

reveals sub-surface features, 1mm resolution

Optical Medical Imaging Program at NIST

*instrument is currently in demo mode

Fast

tunable white

light laser source

Calibrated Hyperspectral imaging: imaging with a palette of 100s of contiguous spectral

bands. Each pixel has a full spectrum and can reveal

chemical information about a region.

Tissue Oximetric

Imaging ( surgery, combat and

diabetic wounds)

[Hb

O2]/

[Hb

]

Jeeseong Hwang, David Allen, Toni Litorja (PML) Antonio Possolo (ITL)

Emerging Application Areas:

NIST Workshop on “Standards for the Advancement of Optical Medical

Imaging,” August 26-27, 2014 NIST Gaithersburg, Maryland

“Wet” and digital

phantoms

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Virtual/ numerical phantom for modeling clinical tumors

Adele Peskin, Alden Dima, Charles Fenimore, James Filliben, Joseph Chen, Richard Rivello (Information Technology Laboratory)

Realistic CT lung tumor data (virtual phantom) with known tumor volumes based on clinical tumors

Embed synthetic tumors in DICOM data sets from NCI RIDER at two time points to determine accuracy of volume change measurements

Clinical tumor

Synthetic tumor

Tumor +

blood vessels

vascular/

partial volume

NV lung tissue

Pixel value (Hounsfield units) Peskin Lecture Notes in Computer Science

(LNCS) series pp. 736 - 746 2010

NIST/ISMRM MRI System Phantom

Measures: • Geometric distortion, B1 uniformity, B0 uniformity, T1, T2,

Proton density, resolution, slice thickness, SNR

Purpose: Scanner QC and inter-scanner comparison, verify T1

T2 mapping protocols, off-the-shelf validation for some clinical trials

First MRI phantom

with NIST traceability,

temperature and field

corrections, stability

monitoring

MRI Phantoms: must cover large parameter space

T1 Array

T2 Array

PD Array

100 100010

100

1000

Connective

CSF

Fat

Glial Matter

Kidney

LiverMuscle

Skin

White Matter

Liver Skeletal muscle Heart

Kidney

Cartilage 0°

Cartilage 55°

White matter

Gray matter

Optic nerve Spinal cord

Blood

10%

25%

40%

Olive oil

Heavy mineral oil

Fat mimic

Fibroglandular mimic

Fiducial Array

NiCl2 array

T2

(m

s)

T1(ms)

T2-T1 plot @ 1.5T for:

NiCl2 & MnCl

2 array @ 20C

and selection of tissues @ 37 C

MnCl2 array

contrast enhanced

PVP

• Phantoms contain

materials with well

defined parameters!

• Many other dimensions

required to mimic tissue:

diffusion, conductivity,

susceptibility!

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T1-Inversion Recovery gold standard:

Need to understand variability

17 18 19 20 21 22 23 24 25 26 27 280.57

0.58

0.59

0.60

0.61

0.62

0.63

0.64

0.65

r1 (

1/s

)

Temperature (C)

NiCl2 @ 1.5 T

5%

• Need in-situ thermometry for

accurate phantom measurement

comparisons.

• Arrays have large ranges with

short and long T1s, T2s that can

be challenging to measure

Katy Keenan

10 100 1000-20

-15

-10

-5

0

5

10

15

20

Err

or

(%)

Target T1 relaxation time (ms)

NIST 1.5 T 20.12 C 11TI

MDACC 1.5T-11TI

MGH 1.5T-12TI

Cin 1.5T-6TI

MGH 3TB6-11TI

MGH 3TB4-10TI

CUINC3T-9TI

UCD BIC 3T-10TI

Error = 100*(T1measured

-T1)/T1

272.9 4.1 ms

CoV=1.5%

T1 Variable Flip Angle: Large variations in

practical mapping sequences

NIST/ISMRM

system phantom

T1 array

Katy Keenan

Standard protocol:

7 flip angles

NIST/UCSF Universal Breast Phantom

Katy Keenan NIST, Nola Hilton UCSF

• For ACRIN 6698/ISPY 2 DWI Biomarkers

for Assessment of Breast Cancer

Response to Neoadjuvant Treatment

• T1, diffusion, geometric distortion, and

tissue mimics

normal

benign

malignant

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Do precise measurements of NMR parameters

make sense in tissue?

MRI measures apparent T1,

apparent T2 and apparent

diffusion coefficient!

T2 of olive oil used in

breast phantom

Need pragmatic but

rigorous definitions?

TE (s)

sig

nal

Many peaks each

with its own T1, T2

Mike Boss

CPMG (NMR)

SE (NMR/MRI)

FSE (MRI)

Breast Phantom: T2 ground truth?

Material

1.5 T 3.0 T

MRI Multi-Echo Spin

Echo

NMR CPMG*

t = 1.0ms

NMR Multi-Echo Spin

Echo* TE=15ms

NMR CPMG*

2.26 mM NiCl2 & 0.25 mM MnCl2 in water

55 ms 57.8 ms 39.0 ms 38.8 ms

35% w/w Corn Syrup in water

261 ms 266 ms 47.3 ms 84.7 ms

Grapeseed Oil

40 ms 160 ms 32.5 ms 171.8 ms

MRI measurements at 16.5 deg C. NMR measurements at ~20 deg C. * Integrated over all peaks

Spin echo includes chemical exchange r2 Dw2 B02

Mike Boss/ Katy Keenan

SI traceability for MRI?

•Traceability in MRI not established

(exception dimensional traceability through

optical interferometry)

•composition traceability for Ni and Mn

concentrations NIST Nickel SRM 3136 and

Manganese SRM 3132 Standard Solutions using

inductively coupled plasma optical emission

spectroscopy (ICPOES).

• NIST can offer traceable measurements of T1,

T2, ADC, susceptibility … using calibrated

variable field, variable temperature NMR ,

magnetometry if we can agree on suitable

definitions!

directly traceability to NIST

PET dose calibrator

System phantom reference

libraries

phantom reference libraries

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NIST Perspective/ Goals

• NIST is ramping up biomedical imaging standards for

quantitative biomarkers

• Goal: extend precise traceable measurements inside the

human

• Assist developing/ validation MR phantoms: anisotropic

diffusion, active flow/perfusion

• NIST will help facilitate a roadmap for standards for

quantitative MR

• NIST will investigate a study of economic impact of

standards-based quantitative MR

Workshop on Standards for Quantitative MR

NIST Boulder July, 2014

NIST MRI standards team: Mike Boss, Katy Keenan, Karl Stupic