M. Wissmeyer Department of Nuclear Medicine, University of Berne (Inselspital) PET/CT in Radiation Oncology: Current Evidence and Future Perspectives

Where is the Target?

PET-CT: Technical Changes  New Detector Technology  Improved spatial resolution  Reduced time for acquisition of PET scans  Implication of CT  Improved correction for attenuation and scatter  Correlation of morphology and metabolism  Reduced time of acquisition

„Conventional“ Planning in Radiotherapy  Diagnostic Tools: CT, PET, MRI…  Dedicated Planning CT-scan  Definition of Target Volumes => Radiotherapy Plan  Simulation  Radiotherapy

„Modified“ Planning in Radiotherapy  Diagnostic Tools: CT, PET/CT, MRI…  Dedicated Planning CT scan + 3D-Fusion with PET/CT scan  Definition of Target Volumes on Fused Scans => Radiotherapy Plan  Simulation  Radiotherapy

Technical Requirements I  Dedicated Radiotherapy Table and PET/CT Unit  Intrinsic Laser for Patient PET/CT  DICOM Data Transfer to Radiation Oncology

 Image-Fusion-Tool in RT Planning-Software  Transfer of Table Position Data to Planning-Software  If dedicated 3D PET/CT:  PET/CT Scan and Dedicated Planning CT as „One-Stop-Shop“  Virtual Simulation on PET/CT Data feasible Technical Requirements II

Pitfalls in Target Volume Definition based on PET/CT Nestle et al.; J Nucl Med (Aug.)

Impact of PET/CT on Target Volume Definition  Avoidance of ‚Geographic Miss‘  Enlargement of Target Volume  Requirement: High Sensitivity and Specificity  Protection of non involved Tissue  Decrease of Target Volumes  Requirement: High Sensitivity

 PubMed: 1200 Entries for „PET Radiotherapy“  PET/CT: Impact on Target Volume Definition since early 2000‘s  Large number of studies but small collectives  Up to now no relevant prospective stuedies and long term outcomes Current Evidence

A. van Baardwijk et al.; Cancer treatment reviews 2006 Metaanalysis

 Studies until August 2005  Only one Study (Daines et al. 2004) providing Correlation with Histologic Findings  Variable Impact of PET/CT on Target Volume Definition A. van Baardwijk et al.; Cancer treatment reviews 2006 Metaanalysis

 Improved Target Volume Definition  Avoidance of Organs at Risk (OAR)  Potential Dose Escalation in Target Volume  PET/CT During Radiotherapy:  Therapy Monitoring  Predictor for Outcome A. van Baardwijk et al.; Cancer treatment reviews 2006 Metaanalysis

 Van Baardwijk et al. 2006:  6 Studies (n=139; 4-40/Study)  Comparison of GTV CT and GTV PET/CT  2 Studies: No relevant Difference in Target Volumes  4 Studies: GTV PET/CT < GTV CT Head and Neck Cancer

G.P., m, 46y; LN-Metastasis of Hypopharynxcarcinoma Head and Neck Cancer: Example

 Van Baardwijk et al. 2006:  4 Studies (n=51; 6-25/Study)  Comparison GTV CT and GTV PET/CT  1 Study: No Difference in Target Volume Definition  2 Studies: GTV PET/CT < GTV CT  1 Study: Average Change of Target Volume 26%  Messa et al. 2005: Improved Detection and Delineation of Atelectases Lung Cancer

Senan et al. (2005), Crit Rev Oncol Hematol NSCLC: Avoidance of Geographic Miss

C. Messa et al.; Q J Nucl Med Mol Imaging 2006 NSCLC: PET/CT During Radiotherapy

Moureau et al. IJROBP 2005 Increased Target Volume in Oesophageal Carcinoma

 Van Baardwijk et al. 2006:  2 Studies (n=41)  Lee et al. 2004: In 6/10 Cases Decrease of Target Volume  Dizendorf et al. 2003: in 8% additional Lymphnodes, Change of Target Volume in 4% PET/CT in Lymphoma

 Van Baardwijk et al. 2006:  2 Studies (n=46)  Ciernik et al. 2003: In 3/6 (!) Cases Increased Target Volume (Additional Lymph Node Metastases)  Lammering et al. 2004:  Good Correlation between CT- and PET/CT-based Target Volumes  Significant Increase of Target Volume in 6/40 Patients Colorectal Carcinoma

 Van Baardwijk et al. 2006:  2 Studies 1998, 2005: Different Tracers (FDG, 11 C-Methionine)  GTV PET/CT << GTV MRI Brain Tumours

 Poor Amount of Data for:  Breast Cancer and other Gynecologic Tumours  Bladder Cancer  Prostate Cancer Other Tumours

 21 consecutive patients  9 male, 12 female  Age range years Own Experience: Patient Data

Own Experience: Tumours I  NSCLC:n=6  Lymphoma: n=4  Gastrointestinal Tumours: n=5  Head and neck cancer:n=2

 Prostate cancer: n=1  Medullary thyroid cancer: n=1  Cancer of Meibom gland:n=1  Cancer of uterine cervix:n=1 Own Experience: Tumours II

 PET alone:n=9  Integrated PET/CT:n=12  PET-Tracers:  18 F-FDG:n=19  18 F-DOPA:n=1  18 F-Choline:n=1 Own Experience: Devices / Tracers

 Omission of EBRT: n=3  Extent of presumed volume: n=2  Distant metastases:n=1  EBRT (LINAC):n=18  3D conformal RT:n=11  IMRT:n=6  Stereotactic RT:n=1 Own Experience: Impact of PET on Indication for EBRT

H.A., f, 68y; NSCLC; Additional Bone Metastases Example: Omission of EBRT

 Target volume delineation by PET/CT:2/18  Increased target volume:6/18  Decreased target volume:3/18  Unchanged target volume:7/18 Own Experience: Impact on Target Volumes

VN.C., f, 34y; Cancer of Cervix Uteri; Additional Retroperitoneal Metastases Example: Increased Target Volume

W.L., f, 61y; NSCLC; No Contralateral Involvement Example: Decreased Target Volume

 Dedicated 3D-RT PET/CT Unit  Virtual Simulation  4D-PET/CT:  Respiratory Gating  Heart Gating  Use of SPECT/CT? New Horizons: Nuclear Medicine

C. Messa et al.; Q J Nucl Med Mol Imaging 2006 New Horizons: Nuclear Medicine

 Extended Use of PET/CT in GI-Tumours  Soft Tissue Sarcomas New Horizons: Nuclear Medicine

V.K., f, 55y; Recurrence of Cholangiocarcinoma

 Markers of Hypoxia and Proliferation => „Dose-Painting“ in IMRT  Acetate / Choline;  Aminoacids: e.g. Brain Tumours  Prostate Cancer:  68 Ga-DOTA-BOM  Neuroendocrine Tumours: 68 Ga-Peptides New Horizons: Nuclear Medicine

G.N., 8y, f; Recidive of anaplastic Oligodendroglioma WHO Grade III Brain Tumours: 18 F-FET-PET/CT

S.W., m, 64y; Bone Metastasis of Atlas Prostate Carcinoma: 18 F-Choline PET/CT

68 Ga-DOTABOM PET in Prostate Carcinoma Prostata-Ca rechts Prostata-Ca links New Horizons: Nuclear Medicine

 Virtual Simulation  On-Board Imaging  Extended Use of IMRT New Horizons: Radiation Oncology

On-Board Imaging

 Tomotherapy?  Gamma-Knife?  Stereotaxia?  Brachytherapy? New Horizons: Radiation Oncology

C. Messa et al.; Q J Nucl Med Mol Imaging 2006 New Horizons: Radiation Oncology

 Need for Provision of Technical Requirements  Feasibility Proven Using FDG-PET/CT  Currently available Data insufficient Conclusions I

 Need for Prospective Studies  New Horizons in Nuclear Medicine and Radiation Oncology  Interdisciplinary Team Work Indispensable Conclusions II