Alan Pollack, M.D., Ph.D.
MR Simulation
University Of Miami
Sylvester Comprehensive Cancer Center
Prostate Anatomy
MR Simulation For
Prostate Cancer
MRMR-CT Fusion
Functional Imaging
Therapeutic Implications
1
2
Prostate Anatomy
The Benefit Of MRI
McLaughlin et al, IJROBP 2005
Prostate Apex
ProstateProstate-rectal interface
Penile Bulb
Tumor Location/Extent
BladderBladder-Prostate Interface
Seminal vesicles
Pelvic vessels
Lymph nodes
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4
Page
Case 3 High Risk CTCT-Sag
Apex Not WellWell-Visualized
Prostate Anatomy
McLaughlin et al,
IJROBP 2005
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6
Case 3 High Risk MRIMRI-Sag
Apex Better Visualized
Case 3 High Risk Coronal
CT
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8
Page
Case 3 High Risk Coronal
MRI
CT Overestimates Prostate
Volume
Roach et al, IJROBP 1996:
“The mean prostate volume was 32% larger…”
larger…”
by CT
Rasch et al, IJROBP 1999:
The “average ratio between the CT and MR
volumes was 1.4”
1.4”
“CTCT-derived prostate volumes are larger than MR
derived volumes, especially toward the seminal
vesicles and the apex of the prostate.”
prostate.”
9
10
Retrograde Urethrogram vs MRI
For Defining The Prostate Apex
MRI vs CT: GTV Delineation
MR
Rasch et al, IJROBP 1999
Milosevic et al 1998 Radioth Oncol: ∼80% agreement between CT
urethrogram and MR.
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CT
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Page
Penile Bulb/Cavernosal
Bulb/Cavernosal Bodies
Case 3 High Risk: Slice 89
Tumor
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14
MRI vs. CT: Hip Replacement
MR Simulation
Prostate Anatomy
MRMR-CT Fusion
Functional Imaging
Therapeutic Implications
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16
Page
MR-CT fusion based on boney anatomy
MR Simulation
Mismatch arises from
time of scan differences
Contoured on CT
1.5 T, 60 cm bore
No fiducials or Gold fiducials :
CT Sim First
Calypso Beacons
MR Sim first
Fusion based on bone and
soft tissue.
MR-based prostaterectum interface
Contoured on MR
Courtesy of Bob Price
• Retrograde urethrograms are not
Courtesy of Bob Price
performed.
MR And CT With Gold Fiducials
Overlap (not including PTV)
MRI
CT
CT-based prostaterectum interface
Courtesy of Bob Price
Courtesy of Bob Price
Page
Note that the
prostate is in a
different position
relative to the
femoral heads
CT With Calypso Beacons
MRI
CT
Courtesy of Bob Price
Note that the
prostate is in a
different position
relative to the
femoral heads
22
MRMR-CT Fusion
MR Simulation
Don’
Don’t outline from MR for soft tissue if there
is discrepancy in the soft tissue
Prostate Anatomy
Fusion should be based on both soft tissue and
bony anatomy
MRMR-CT Fusion
Gold markers on MR and CT can aid in soft
tissue fusion
Calypso beacons are on CT only and MR
should only be used as a reference (all
outlining from CT)
Functional Imaging
Therapeutic Implications
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Page
Imaging To Identify Bulky
Tumor Regions
How Can BulkyBulky-HypoxicHypoxic-Microvessel Dense
Areas Be Identified And Better Targeted?
Testa et al, Radiology 2007
Pretreatment
MR
Target with EBRT boost, EBRT+Brachy boost,
EBRT+Cryosurgery boost, EBRT+FUS boost
MRMR-Guided FUS
Reduce incidence of Bx+
Bx+ at 22-3 yr
MRS, Bold, DCE, DW
PET
11C11C-Choline, 11C11C-Acetate
Spect
PostPost-treatment
PSMA
Biopsy at 22-3 years
Decision to Bx based on imaging?
Target residual tumor before PSA rise
Treatment of residual tumor cells only
25
Is Failure Related To High
Volume Areas?
Left
Target with
imaging
PostPost-Treatment Biopsy Results
Right
0/1
3+4
1/1
5%
4+3
1/1
20%
Base
4+3
1/1
30%
4+3
1/1
70%
0/1
0/1
Mid
4+3
1/1
50%
3+4
1/1
50%
3+4
1/1
<5%
TZTZ- Left: 0/0
TZTZ-Right: 0/0
0/1
0/1
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Left
Target with
imaging
Right
0/1
0/1
0/1
Apex
0/1
0/1
0/1
Base
4+3
1/1
15%
0/1
0/1
Mid
3+4
1/1
5%
TZTZ- Left: 0/0
TZTZ-Right: 0/0
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Page
0/1
0/1
Apex
28
Pucar et al, IJROBP 2007
9 Patients
PrePre-RT and PostPost-RT MRI
Salvage Prostatectomy
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30
31
32
Page
Prostate
Boost
S
Prostate
Boost
Target
Boost
Target
I
10 Gy, 9, 8, 7, 6, 5
76 Gy, 68, 61, 53, 46, 38
10 Gy, 9, 8, 7, 6, 5
EQD2 = D[(d + ( / ))/(2 + ( / ))] = 30 Gy { /
Price & Pollack
76 Gy, 68, 61, 53, 46, 38
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30 Gy, 27, 24, 21, 18, 15
prostate
30 Gy, 27, 24, 21, 18, 15
= 2.0 Gy}
Gy}
34
Price & Pollack
Pickett et al, MRSI In FollowFollow-up
After EBRT
Pretreatment
Post-treatment
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36
Page
Pre-contrast
Pre-contrast
Benign : Post-contrast
Malignant : Post-contrast
Lymphotropic Superparamagnetic
Nanoparticle lymph node imaging
agents (Combidex)
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MR Imaging For Prostate Cancer
There are gains in the use of MR
imaging in RT planning and delivery,
and in followfollow-up.
Need to test and incorporate better
imaging methods for identifying
bulkybulky-hypoxichypoxic-microvessel dense
disease
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