What is dose painting Barbara Vanderstraeten Ghent University

What is dose painting? Barbara Vanderstraeten Ghent University Hospital 19 January 2008

Outline I. III. IV. Introduction Technical solution Planning studies Conclusions

I. Introduction

Imaging for RT From V Grégoire

Anatomical imaging • CT • MRI

Biological imaging • • PET SPECT f. MRI MRSI Brain Tumor

Tumor biology characterization Radiotracer Characterization 18 F-FDG Glucose metabolism 18 F-FLT DNA synthesis 11 C-MET Protein synthesis 60 Cu-ATSM, 18 F-FMISO Hypoxia Radiolabeled Annexin V Apoptosis Radiolabeled a. Vb 3 integrin antagonists Angiogenesis S Apisarnthanarax and KSC Chao. Radiat Res 2005; 163: 1 -25.

Biological imaging for RT • Improvement of diagnostic and staging accuracy • Guidance of target volume definition and dose prescription • Evaluation of therapeutic response

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. J Radiat Oncol Biol Phys 2000; 47: 551 -60. Int

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 18 F-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 Dhigh Dlow Ihigh Signal intensity

Treatment plan optimization B Vanderstraeten et al. Phys Med Biol 2006; 51: N 277 -86

Treatment plan evaluation QVH

Example: 18 F-FDG-PET-guided BCRT for oropharyngeal cancer

III. Planning studies • Feasibility of BCRT • 18 F-FDG-PET-guided BCRT for head and neck cancer B Vanderstraeten et al. Radiother Oncol 2006; 79: 249 -58 • 18 F-FMISO-guided BCRT for head and neck cancer D Thorwarth et al. Int J Radiat Oncol Biol Phys 2007; 68: 291 -300

Feasibility of BCRT • 18 F-FMISO-PET-guided BCRT for a base-of-tongue cancer case M Alber et al. Phys Med Biol 2003; 48: N 31 -5 • 18 F-FDG-PET- and 99 m. Tc-MAA-SPECT-guided BCRT for 2 lung cancer cases DK Das et al. Med Phys 2004; 31: 1452 -61 • 18 F-FDG-PET- guided BCRT for an oropharyngeal cancer case B Vanderstraeten et al. Phys Med Biol 2006; 51: N 277 -86

18 F-FDG-PET-guided BCRT for head and neck cancer

Set-up • 15 head and neck cancer patients • 18 F-FDG-PET imaging of tumor metabolism • Dose painting by contours (“contour-based IMRT”) versus dose painting by numbers (“voxel intensitybased IMRT”) • Comparison of clinically relevant dose-volume characteristics – Between “cb 250” and “vib 216 -250” – Between “vib 216 -250” and “vib 216 -300” • DVHs

Target dose prescription “cb 250” “vib 216 -250” (c. Gy/fx) PTVPET “vib 216 -300” (c. Gy/fx) 250 PTV 69+PET 216 - 250 216 - 300 PTV 69 216 PTV 66 206 206 PTV 62 194 194 PTV 56 175 175

“cb 250” (blue) versus “vib 216 -250” (green)

“vib 216 -250” (green) versus “vib 216 -300” (orange)

Example

Treatment plan evaluation

18 F-FMISO-guided BCRT for head and neck cancer • 13 head and neck cancer patients • 18 F-FMISO-PET hypoxia imaging • Comparison of – Conventional IMRT – 18 F-FDG-PET-guided dose painting by contours – 18 F-FMISO-PET-guided dose painting by numbers • DVHs, TCP

18 F-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

Fundamental research in vitro, animal studies Biological imaging • Tracers • Acquisition, reconstruction, quantification Treatment planning and delivery • Biological optimisation • Adaptive RT Clinical investigations Treatment outcome