8/15/2011
OUTLINE
 Imaging for treatment prognosis (pre-tx) or
treatment monitoring (pre- vs. post-tx)
 Head-and-neck treatment monitoring study at
Shiva Das, Ph.D.
Radiation Oncology
Duke University
FDG-PET HETEROGENEITY:
ESOPHAGEAL CANCER
Textural nature of FDG-PET can significantly identify responder,
non-responder and partial responders (esophageal cancer,
chemo-radiotherapy).
Tixier et al., Journal of Nuclear Medicine.
2011;52(3):369-78
Duke.
 Treatment planning guidance with imaging.
DCE-MRI ENHANCEMENT: CERVICAL CANCER
DCE-MRI subtraction between pre-contrast and enhancement
at 18s, 78s, 138s is inversely correlated (very significant) to
chemoradiotherapy response(tumor volume regression) in
patients with cervical cancer
Mannelli et al. American Journal of
Roentgenology. 2010;195(2):524-7
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PERFUSION CT: LUNG CANCER
Higher perfusion (measured using perfusion CT) in non-small cell
lung cancer prior to therapy correlated to early tumor response
and better overall survival.
Wang et al, American Journal of
Roentgenology. 2009;193(4):1090-6.
HYPERPOLARIZED HELIUM
MR ADC (VENTILATION): LUNG
Pre-RT: Strong correlation between extent of CT-defined emphysema
and whole lung ventilation (r = 0.9)
Post-RT: Reduction in ventilation correlated to pneumonitis in 3/5
cases.
Ireland et al. Radiotherapy and Oncology
97(2): 244-248.
HYPERPOLARIZED XENON MR ADC (VENTILATION/GASEXCHANGE): LUNG
diffusion
alveolus
gas
exchange
 Diffusion (ventilation): MR ADC with helium/xenon
 Blood flow: SPECT
 Gas exchange: MR with xenon
 Strongly correlated to FEV1.
 Strongly correlated to DLCO.
 Significant differences between healthy and COPD.
Kaushik et al. Magnetic Resonance in
Medicine 65(4): 1155-1165.
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SINGLE PHOTON EMISSION COMPUTED
TOMOGRAPHY (PERFUSION): LUNG
DCE-MRI, DW-MRI: BRAIN GLIOMAS
 Recurrent gliomas < 5 cm size.
 Treated with 1 – 5 fraction SRS + bevacizumab.
 DCE-MRI and DW-MRI imaging prior to therapy,1 wk
post therapy and 2 month post therapy.
DCE-MRI
KTRANS
Pre-RT:
 Mean regional dose correlated to RP in all regions except anterior,
cranial, and contralateral regions.
 Mean perfusion-weighted regional dose correlated to RP in all
regions except anterior
Seppenwoolde et al. International Journal of
Radiation Oncology Biology Physics 60(3): 748-758
DCE-MRI, DW-MRI: BRAIN GLIOMAS
Courtesy Alvin Cabrera
HEAD-AND-NECK CANCER
 18 patients
ADC MAP
 Underwent FDG-PET, DCE-MRI and DW-MRI at
o baseline (2 scans separated 1 week prior
to CRT),
o ~1 week after start of CRT, follow-up PET
after CRT.
 Structures: GTV, Nodes, Parotids
Can intra-CRT imaging predict for
 tumor response (CR, PR, SD, PD)?
 salivary flow decrease?
Courtesy Alvin Cabrera
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PET BASELINE VARIATION
DCE-MRI EVF BASELINE VARIATION
DCE-MRI KTRANS BASELINE VARIATION
DCE-MRI AUC BASELINE VARIATION
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DW-MRI ADC BASELINE VARIATION
DCE-MRI KTRANS BASELINE SIGNIFICANCE
PET BASELINE SIGNIFICANCE
DCE-MRI EVF BASELINE SIGNIFICANCE
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DCE-MRI AUC BASELINE SIGNIFICANCE
DW-MRI ADC BASELINE SIGNIFICANCE
NODAL DOSE RESPONSE
FDG-PET
DCE-MR EVF
GTV DOSE RESPONSE
DW-MR ADC
DCE-MR AUC
DCE-MR KTRANS
FDG-PET
DCE-MR EVF
DW-MR ADC
DCE-MR AUC
DCE-MR KTRANS
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COMPARISON OF IMAGE MODALITIES
PAROTID DOSE RESPONSE
FDG-PET
DW-MR ADC
Parotids (FDG-PET vs MRI AUC):
Correlation = -0.29 (weak negative)
DCE-MR EVF
DCE-MR AUC
DCE-MR KTRANS
Greater parotid leakiness → less washout → higher
area under curve?
COMPARISON OF IMAGE MODALITIES
Pre-RT
PET
ADC
Intra-RT
Parotids (FDG-PET vs MR ADC):
Correlation = -0.23 (weak negative)
Radiation damage → increase in extracellular space
ADC
ADC, PET after a
few treatments.
PET
VelocityAI software
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TREATMENT PLANNING
Imaging modalities generally have low correlation.
Good – since they are then capable of providing
complementary information.
Tailor treatment planning to image information:
 Using pre-treatment imaging information.
 Change in imaging parameters between pre-tx
and intra-tx.
Awaiting completion of patients …….
Can intra-CRT imaging predict for
 tumor response (CR, PR, SD, PD)?
 salivary flow decrease?
 Increase dose to hyperactive/resistant tumor
regions.
 Decrease dose to highly functional regions of
normal organs.
Serial imaging of 62Cu-ATSM
followed by 62Cu-PTSM
trapping rate
oxygen availability  PTSM - ATSM
PTSM-ATSM TRAPPING RATE
(OXYGEN AVAILABILITY)
ATSM TRAPPING RATE
The low oxygen concentration region “A”
corresponds to high ATSM uptake (as
expected).
However, the low oxygen
concentration region “B” corresponds to
low ATSM uptake.
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DECREASE DOSE TO FUNCTIONAL REGIONS OF NORMAL ORGANS
STRATEGY: INCREASE DOSE TO MORE HYPOXIC REGIONS
Hyperpolarized Helium to identify regions of functional
lung.
 How much more dose do hypoxic regions
require to achieve spatially uniform local control?
 How does cycling hypoxia affect map?
V20 for well ventilated lung was significantly reduced.
Ireland et al. International Journal of Radiation
Oncology Biology Physics 68(1): 273-281.
DECREASE DOSE TO FUNCTIONAL REGIONS OF NORMAL ORGANS
SPECT to identify functional lung for dose avoidance
SPECT-guided vs. Conventional Plan: mean dose in SPECT
regions
Overall mean lung dose reduction: 3.2 vs. 3.7 Gy (13% )
1st Highest SPECT region: 1.2 Gy vs. 2.4 Gy (49%)
2nd Highest SPECT region: 4.6 Gy vs. 6.7 Gy (32% )
3rd Highest SPECT region: 3.4 Gy vs. 4.1 Gy (17% )
4th Highest SPECT region: 2.1 Gy vs. 2.4 Gy (13% )
Remaining “non-perfused”: 3.45 Gy vs. 3.42 Gy (1%)
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CONCLUSIONS
 Imaging (PET/MR/SPECT) shows great promise in
predicting treatment outcome:
o Pre-tx imaging
o Pre- and intra-tx imaging
 Predictive abilities may be used to guide tx planning:
o Avoid highly functional regions
o Escalate dose to more active tumor regions (how
much?)
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