Transcript 18F-Choline: Is shine-through effect an issue for prostate SUV

18F-Choline: Is shine-through effect an issue
for prostate SUV quantification?
J E S Ú S S I LVA - R O D R Í G U E Z , PA B L O AG U I A R ,
I N É S D O M Í N G U E Z - P R A D O, M I C H E L H E R R A N Z , Á LVA RO
RU I B A L
Introduction: Imaging on prostate cancer
Imaging techniques such as CT, MRI and TRUS are useful, but have
demonstrated limited sensitivity
PET and PET/CT could potentially increase accuracy for the diagnosis of
prostate cancer
FDG showed limited sensitivity for the detection of prostate carcinomas
and local recurrence
NEED: New radiotracers
Farsad et al: “PET/CT and choline: diagnosis and staging.”. Q J Nucl Med Mol Imaging. 2012
Introduction: Choline
Introduction: Choline in prostate cancer
11C-choline and 18F-choline are increasingly prescribed for:
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•
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Biochemical recurrence.
Clinically suspected prostate cancer, with multiple negative biopsies.
Patient stratification with respect to surgery or radiotherapy.
Lymph node and bone metastasis.
Schwarzenböck et al: “Choline PET and PET/CT in Primary Diagnosis and Staging of Prostate Cancer”. Theranostics. 2012
Introduction: Choline in prostate cancer
NEXT STEP: Diagnosis of primary prostate cancer.
First clinical studies presented partially controversial results.
Detection sensitivity (73%-100%) and specificity (67-98%).
Introduction: SUV in prostate cancer
Attempts to use quantitative parameters such as SUV has
also delivered mixed and contradictory results
Tissue
18F-Choline SUV
Normal prostate tissue.
1.4-3.1
Prostate cancer.
1.7-6.2
Local Recurrence
2.7-12.42
QUESTION: Is F18-choline suitable for the use of
these quantification values?
Introduction: Shine-Through
Liu et al: ”Invalidity of SUV Measurements of Lesions in Close Proximity to Hot
Sources due to “Shine-Through” Effect on FDG PET-CT Interpretation” Radiology
Research and Practice 2012
Introduction: 11C vs 18F choline
The main difference is the early appearance of 18 F-Choline in the
urinary tract due to an incomplete tubular re-absorption
Introduction: Shine-Through
QUESTION: Is shine-through a problem for the use of SUV
measurements in 18F-choline scans?
Methods: Experiment Workflow
Our Workflow:
18F Choline
Phantom
Scatter & att
correction
Reconstruction
Sinograms
MonteCarlo
simulation
(SIMSET)
Tomographic
reconstruction
(STIR)
Theo. Prostate SUV
Theo. Bladder SUV
Estimated
prostate SUVs
Comparison
Silva-Rodriguez et al: “Simulated FDG-PET studies for the assessment of SUV quantification methods”. Rev Esp Med Nucl Ima Mol 2014
Methods: Experiment Workflow
Methods: Phantom
A single patient representing the average Spanish man (172
cm, 76 Kg) was generated using the XCAT phantom*.
The bio-distribution of choline was derived from literature
A hot spot was added in the prostatic left lobe to emulate a
primary prostate tumor or local recurrence (24 cm3).
(*) Seagars et al: “4D XCAT phantom for multimodality imaging research.” Med. Phys. 2010
Methods: Scanner
The simulated scanner geometry was based on the GE Advance Nxi.
Attenuation, scatter correction and reconstruction were also based
on the protocols performed by this scanner.
Silva-Rodriguez et al: “Correction for FDG PET dose extravasations: Monte Carlo validation and quantitative evaluation of real patient studies” Med Phys 2014
Methods: Simulation and Reconstruction
 Total injected dose was 370 MBq for all the
studies.
 Studies were simulated for
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
Lesion SUVs of 3.03 and 6.06
Bladder SUVs of 1.1, 3.03, 7.58, 13.64, 15.92
 SIMSET package was used to perform the
simulation. (5 repetitions/point)
 Sinograms were reconstructed using the
STIR library OSEM. (stir.sourceforge.net)
 SUVmax was measured on the simulated
lesion for all the lesions.
Thielemans et al: “STIR: Software for Tomographic Image Reconstruction Release 2” , PMB 2012
Results
Measured Tumor SUV (g/l)
4.6
+41.3%
4.4
+27.4%
4.2
+24.1%
4
+19.8%
3.8
3.6
3.4
3.2
+5.6%
+1.7%
Theoretical SUV = 3.03
3
2.8
0
5
10
Bladder SUV (g/l)
15
20
Results
+23.4%
Measured Tumor SUV (g/l)
7.7
7.5
+16.2%
7.3
7.1
+7.9%
6.9
6.7
6.5
6.3
6.1
+0.1%
+0.7%
-2.3%
Theoretical SUV = 6.06
5.9
5.7
0
5
10
Bladder SUV (g/l)
15
20
Results
60
SUV Increase (%)
50
40
30
20
10
0
-10
R² = 0.8529
-20
0
1
2
3
4
Bladder/Tumor SUV Ratio
5
6
Discussion
Urinary excretion and high accumulation in the bladder can
compromise not only detectability, but also quantification
results when using 18F-choline (up to 40%).
The effect becomes specially relevant when bladder SUV is
higher than the lesion SUV, showing a strong dependency on
tumor/bladder ratio.
Avoiding bladder accumulation is essential for an accurate
quantification of lesions on the prostatic region
Conclusions
Bladder accumulation of 18F-choline significantly biased the
measurements of prostatic lesions SUV
11C-choline might be more reliable for quantitative evaluation
of the prostatic region
If 18F-choline is used, a correction method will be mandatory
for the quantitative evaluation of prostate cancer
Molecular Imaging Reseach Group
INVESTIGADOR PRINCIPAL:
Álvaro Ruibal Morell
Professor of Radiology and Medical Physics, University of Santiago de Compostela
Head of the Nuclear Medicine Department, Santiago University Hospital
MIEMBROS DEL EQUIPO
Michel Herranz
Sonia Argibay
Miguel Garrido
Pablo Aguiar
Virginia Pubul
María Pombo
Jesús Silva
Patricia Fierro
Jesús López
Julia Cortés
Inés Domínguez
Alejandro Bejarano
The end