what is dose painting?

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