What is dose painting?
Barbara Vanderstraeten
Ghent University Hospital
19 January 2008
Outline
I. Introduction
II. Technical solution
III. Planning studies
IV. Conclusions
I. Introduction
Imaging for RT
From V Grégoire
Anatomical imaging
• CT• MRI
Biological imaging
• PET• SPECT• fMRI• MRSI
Brain
Tumor
Tumor biology characterization
Radiotracer Characterization
18F-FDG Glucose metabolism
18F-FLT DNA synthesis
11C-MET Protein synthesis
60Cu-ATSM, 18F-FMISO Hypoxia
Radiolabeled Annexin V Apoptosis
Radiolabeled V3 integrin antagonists
Angiogenesis
S Apisarnthanarax and KSC Chao. Radiat Res 2005;163:1-25.
• Improvement of diagnostic and staging accuracy
• Guidance of target volume definition and dose prescription
• Evaluation of therapeutic response
Biological imaging for RT
Target volume definition
• Gross tumor volume (GTV)
• Clinical target volume (CTV)
• Planning target volume (PTV)
Biological target volume (BTV)
CC Ling, J Humm, S Larson et al. Int J Radiat Oncol Biol Phys 2000;47:551-60.
Dose painting
Dose painting by contours
Dose painting by contours
KSC Chao, WR Bosch, S Mutic et al. Int J Radiat Oncol Biol Phys 2001;49:1171-82.
Dose painting by contours
KSC Chao, WR Bosch, S Mutic et al. Int J Radiat Oncol Biol Phys 2001;49:1171-82.
Dose painting by contours
18F-FDG-PET-guided dose painting in head and neck cancer: phase I clinical trial (41 patients)
I Madani, W Duthoy, C Derie et al. Int J Radiat Oncol Biol Phys 2007;68:126-35.
Dose painting by numbers
Dose painting by numbers
Biologically Conformal Radiation Therapy
II. Technical solution
Relationship between signal intensity and radiation dose
Dose
Ilow Ihigh
Dlow
Dhigh
Signal intensity
highlow
lowhighlowhigh
lowlow
IIIfor
)D(DII
IIDD
Treatment plan optimization
B Vanderstraeten et al. Phys Med Biol 2006;51:N277-86
Treatment plan evaluation
0
20
40
60
80
100
0 0.5 1 1.5
Q
Re
lativ
e v
olu
me
(%
)
p
p 1Qn
1QF
presc
pp D
DQ
QVH
Example: 18F-FDG-PET-guided BCRT for oropharyngeal cancer
Example: 18F-FDG-PET-guided BCRT for oropharyngeal cancer
0
20
40
60
80
100
0.85 0.9 0.95 1 1.05 1.1 1.15Q
Vo
lum
e (
%)
2.5 Gy/fx
3 Gy/fx
III. Planning studies
• Feasibility of BCRT
• 18F-FDG-PET-guided BCRT for head and neck cancerB Vanderstraeten et al. Radiother Oncol 2006;79:249-58
• 18F-FMISO-guided BCRT for head and neck cancerD Thorwarth et al. Int J Radiat Oncol Biol Phys 2007;68:291-300
Feasibility of BCRT
• 18F-FMISO-PET-guided BCRT for a base-of-tongue cancer caseM Alber et al. Phys Med Biol 2003;48:N31-5
• 18F-FDG-PET- and 99mTc-MAA-SPECT-guided BCRT for 2 lung cancer cases
DK Das et al. Med Phys 2004;31:1452-61
• 18F-FDG-PET- guided BCRT for an oropharyngeal cancer caseB Vanderstraeten et al. Phys Med Biol 2006;51:N277-86
18F-FDG-PET-guided BCRT for head and neck cancer
Set-up
• 15 head and neck cancer patients• 18F-FDG-PET imaging of tumor metabolism• Dose painting by contours (“contour-based IMRT”)
versus dose painting by numbers (“voxel intensity-based IMRT”)
• Comparison of clinically relevant dose-volume characteristics– Between “cb250” and “vib216-250”– Between “vib216-250” and “vib216-300”
• DVHs
Target dose prescription
“cb250”
(cGy/fx)
“vib216-250”
(cGy/fx)
“vib216-300”
(cGy/fx)
PTVPET 250
PTV69+PET 216 - 250 216 - 300
PTV69 216
PTV66 206 206 206
PTV62 194 194 194
PTV56 175 175 175
“cb250” (blue) versus “vib216-250” (green)
0 30 60 90 120 150 180 210 240 270 300 3300
20
40
60
80
100
Fraction dose (cGy)
Vo
lum
e(%
)
Surr
PTV56
Spared parotid
PTV69+PET
Spinal cordPTV
PET
PTV66
PTV69
MandiblePTV
62
“vib216-250” (green) versus “vib216-300” (orange)
0 30 60 90 120 150 180 210 240 270 300 3300
20
40
60
80
100
Fraction dose (cGy)
Vo
lum
e (%
)
MandiblePTV
62
PTVPET
PTV69+PET
PTV66
PTV69
PTV56
Spinalcord
Sparedparotid
Surr
Example
2.11.2
2.5
2.16
2.22.4
1.6 1.4
2.3
2.11.2
2.5
2.16
2.22.4
1.6 1.4
2.3
2.1
2.5
2.162.2
2.4
1.61.4
2.32.1
2.5
2.162.2
2.4
1.61.4
2.3
2.1
2.5
2.2
2.4
1.62.3
2.1
2.5
2.2
2.4
1.62.3
Treatment plan evaluation
"cb250"
PTV69
"cb250"
PTVPET
"vib216-250"
PTV69+PET
"vib216-300"
PTV69+PET
0
0.5
1
1.5
2
2.5
3
3.5
QF (%)
18F-FMISO-guided BCRT for head and neck cancer
• 13 head and neck cancer patients• 18F-FMISO-PET hypoxia imaging• Comparison of
– Conventional IMRT– 18F-FDG-PET-guided dose painting by
contours– 18F-FMISO-PET-guided dose painting by
numbers
• DVHs, TCP
18F-FMISO-guided BCRT for head and neck cancer
D Thorwarth, SM Eschmann, F Paulsen and M Alber Int J Radiat Oncol Biol Phys 2007;68:291-300.
IV. Conclusions
• The rationale for dose painting is clear
• Dose painting is technically feasible– By contours– By numbers
• Current issues?
See Discussion at 12:30
Treatment planning and delivery
•Biological optimisation
•Adaptive RT
Biological imaging
•Tracers
•Acquisition, reconstruction, quantification
Clinical investigations
Fundamental research in vitro, animal studies
Treatment outcome
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