1. Medical Imaging Workshop Molecular Imaging
Marcelo Tatit Sapienza
INFIERI Summer School
Intelligent signal processing for FrontIER Research and Industry 

2. Molecular Imaging Overview Imaging Modalities
Clinical Applications – e.g. breast cancer

3. Molecular Imaging In vivo Imaging MOLECULAR BIOLOGY
visualisation, characterization and quantification of
normal / pathological biological processes at the
cellular and molecular level
Molecular Imaging emerged as a discipline at the intersection of molecular biology and in vivo imaging

4.  MOLECULAR BIOLOGY Molecular paradigm of diseases Abnormal cells with
pathological phenotypes
Molecular expression

5. Hallmarks of cancer – Cell 2000
Hanahan & Weinberg

6. Probes / ligands may be detected and allow
Abnormal cells with
pathological phenotypes
Molecular expression
Probes / ligands may be detected and allow
Therapy
with labeled compounds
Diagnosis
Identification of targets
for drugs
Therapy response
Therapy planning

7. BASIC / PRECLINICAL RESEARCH CLINICAL APPLICATIONS
Molecular Imaging
BASIC / PRECLINICAL RESEARCH
Study of mechanisms of disease development and progression
Detection and activity of receptors and pathways
Pharmacokinetics / pharmacodynamics of target drugs
CLINICAL APPLICATIONS
Understanding pathophysiological mechanisms
Diagnosis / Staging
Response to target drugs / individualized therapies

8. Translational research
Preclinical
Molecular Target Identification
Development of ligands
Experimental / preclinical evaluation
Clinical
Image in humans  validation
Approval by regulatory agencies
Clinical application

9. Translational research
from BENCH to BEDSIDE to public health
 In a medical research context, it aims to "translate" findings in fundamental research into medical practice and meaningful health outcomes

10. Molecular Imaging Overview Imaging Modalities
Clinical Applications – e.g. breast cancer

11. Imaging Modalities Optical systems Nuclear Medicine: PET / SPECT
MRI
Ultrasonography
Computed tomography
Differences in
Spatial resolution
Depth of evaluation
Ionizing / non-ionizing radiation
Available molecular markers or probes
Detection threshold

12. Imaging modalities
Willmann
Nature Reviews 2008

13. Imaging modalities
Optical Imaging: lower cost  high-throughput screening for targets
low depth penetration  limited clinical translation
Nuclear Medicine: higher cost than optical
unlimited depth penetration  clinical translation
MRI: high resolution and soft tissue contrast / cost and imaging time
US: high spatial and temporal resolution / low cost / limited targets
CT: high spatial resolution / no target specific imaging
Willmann Nature Reviews 2008

14. Spectrum of wavelenghts
Eletromagnetic radiation
MRI
Optical
CT / NM
High energy
Low energy
Infra red
Ultra violet

15. Optical Imaging fluorescence and bioluminescence Reporter gene
Green fluorescent protein
Near Infrared fluorphores (NIR)
Reporter gene
(luciferase)
Prescher Current Opinion in Chemical Biology 2010

16. NM Radiopharmaceuticals
radiolabeled molecules designed for in vivo application:
PHARMACEUTICAL= molecular structure determining the fate of the compound within the organism
RADIO= radioactive nuclide responsible for a signal detectable outside of the organism
e.g. technetium-99m half life 6 hours
gamma-ray photon 140 keV

17. Scintillation camara
Sorenson and Phelps, W.B.Saunders

18. SPECT Single Photon Emission Computed Tomography

19. Positron emitters Nuclides half life Positron: F-18 110 min
C min
N min
O min
Ga min
Rb min
Positron:
Same mass as electron
opposite electrical charge
annihilation generates a pair of gamma-ray photons – 180º

20. PET
Zanzonico Semin Nucl Med 2004

21. SPECT
PET
511 keV
140 keV
SPECT / CT
PET / CT

22. PET SPECT PET > SPECT Spatial resolution (human studies)
Temporal resolution
Sensitivity
Cost

23. Molecular Imaging Requirements
Imaging equipment
Target selection
Development of imaging probe / tracer

24. Development of in vivo probes
< 5% of in vitro targets allow development of an in vivo tracer
High TARGET concentration
Affinity and specificity
Absence of biological barriers (i.e. endothelium, blood brain barrier, ...)
Stable labeling of compound

25. Development of in vivo probes
< 5% of in vitro targets allow development of an in vivo tracer
High TARGET activity / concentration
Affinity and specificity
Absence of biological barriers (i.e. endothelium, blood brain barrier, ...)
Stable labeling of compound
Low BACKGROUND activity
Non-specific accumulation,
Circulating or interstitial activity
Renal or hepatic elimination

26. Development of in vivo probes
< 5% of in vitro targets allow development of an in vivo tracer
High TARGET activity / concentration
Affinity and specificity
Absence of biological barriers (i.e. endothelium, blood brain barrier, ...)
Stable labeling of compound
Low BACKGROUND activity
Non-specific accumulation,
Circulating or interstitial activity
Renal or hepatic elimination
Signal amplification
Cell trapping
Enzymatic conversion
"Reporter" molecules: fluorescence, radiation, magnetic

27. 18FDG fluorodeoxyglucose = glucose analogue
EXAMPLE:
18FDG fluorodeoxyglucose = glucose analogue
Transport (Glut)
Phosphorylation (hexokinase)
Metabolism

28. MOST TUMORS: Increased Aerobic glycolysis (Warburg effect )
Phenotype common to most tumors
Lower production of energy / mol X
NADPH Production - Synthesis
Hypoxia and acidosis select cells resistant to apoptosis
Acid pH associated with invasion
Vander Heiden Understanding the Warburg Effect Science 2009

30. Hanahan & Weinberg Cell 2011
The same authors revisited the main molecular factors related to cancer, increased glycolisis is part of deregulated cellular energetics

31. Molecular Imaging Overview Imaging Modalities
Clinical Applications – e.g. breast cancer

32. Breast cancer Brazil Most incident in women ~ 50 /100,000
new cases ( 2014 – INCA )
deaths:  ( 2011 – SIM )
5 y survival ~ 60 %
LOBULAR
DUCTAL

33. Breast cancer Staging PROGNOSIS and CONDUCT
- T 1 < 2 cm T cm T3 > 5 cm T4 thoracic wall / skin
- N0, 1 axillary I-II mobile, N2 axillary fixed or int.thoracic, N3 infra (III) / supraclavicular /
axillary+int. thoracic
- Metastases M0, M1
AJCC Cancer Staging Manual. 7th ed. 2010,
PROGNOSIS and CONDUCT
Therapy choices considers also :
Clinical conditions, Age , Menopause, Histology of the tumor
Hormone Receptors and HER2

34. Hormone and Growth Factor Receptors expression variation
PREDICTIVE biomarker = susceptibility of the tumor before indicating the therapy

35. personalized cancer therapy
BIOPSY:
TU hormone receptor ++
 susceptible to treatment with drugs that blocks either the estrogen receptors or hormonal synthesis
Biomarker-driven
personalized cancer therapy
Precision
medicine 
It is well known that gene expression may vary in different areas of the same tumor in a single patient. This publication from 2012 shows a primary renal cell tumor with differences in tumor grade from well differentiated to undifferentiated tumor – the metastases may also present marked heterogeneity. This heterogeneity results from the interaction of the tumor cells with its surrounding, acting in a Darwinian selection of clones, form which some are capable of dissemination and metastatic progpagation, others may be quiescent but resistant to a specific therapy, others may act as tumor stem cells.
BUT…

36. Establishing genetic and molecular profile by biopsy may not be sufficient:
Tumor heterogeneity
Gerlinger, Intratumor heterogeneity NEJM 2012

37.  target = hormone receptor
18FES – FLUOROESTRADIOL
 target = hormone receptor
FDG
FES
FDG post-therapy
PREDICTIVE biomarker in breast cancer
( indicates susceptibility to treatment )
Linden JCO 2006

38. 18FES – FLUORO ESTRADIOL
FDG
FES
FDG post-therapy
Linden JCO 2006

39. PET- FDG in the metabolic evaluation after lymphoma chemotherapy
EARLY RESPONSE biomarker
= post-therapy prognosis
PET- FDG in the metabolic evaluation after lymphoma chemotherapy
Reduce or increase # chemotherapy cycles
Change / add therapy
Kasamon JNM 2007

40. 18F-FES – FLUOROTHYMIDINE  target = DNA synthesis
uptake after 1st cycle identifies responders ( p ) - ( n= 15 )
EARLY RESPONSE biomarker in breast cancer
Crippa F Eur J Nucl Med Mol Imaging 2015

41. 18F-FES – FLUORO THYMIDINE
EARLY RESPONSE biomarker in breast cancer
uptake after 1st cycle identifies responders ( p ) - ( n= 15 )
Crippa F Eur J Nucl Med Mol Imaging 2015

42. Conclusion
Molecular imaging is a multidiciplinary field in the intersection of molecular biology and in vivo imaging
Main pillars of MI are :
Use of imaging modalities with different performances
Development of probes/ligands detectable in vivo
MI is part of translational research and may be applied for biomarker-driven personalized therapy
( precision medicine )

43. Thank you !