In-room imaging. ICTR PHE 2012 Geneva, Switzerland, Feb. 29, 2012

Transcription

1 In-room imaging ICTR PHE 2012 Geneva, Switzerland, Feb. 29, 2012 Wolfgang Enghardt OncoRay National Center for Radiation Research in Oncology Technische Universität Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany Institute of Radiation Physics

2 Outline 1. In-room imaging: state of the art 2. Particle beams: Nuclear methods 3. Magnetic resonance imaging and radiotherapy

3 1. In-room imaging: state of the art Patient positioning: steep dose gradients, selective RBE Challenge: precise positioning over ~ 30 daily fractions" The problem of daily patient positioning is multiplied by target movement" intrafractional interfractional" Reduce the errors means:" Imaging, imaging, imaging, but how?" F. Pönisch et al., OncoRay, Dresden, Germany" M. van Herk et al., Netherlands Cancer Institute, Amsterdam, NL"

4 1. In-room imaging: state of the art Requirements to in-room imaging Obtain exact knowledge on" - patient position" - anatomy" in real time during dose delivery for" - reducing treatment margins" - interactive adaption of treatment on the basis of daily" " assessment of changes in tumour volume" general response to therapy (e.g. loss of weight)" PET" PET" Tumour volume " reduction: 49.2 %" " Potential for " tumour dose " escalation" Before treatment" After dose delivery of 50 Gy" D. Verellen et al.: Nature Reviews Cancer 7 (2007) 949 C. Gillham et al. Radiother. Oncol. 88 (2008) 335

5 1. In-room imaging: state of the art Electron linacs state of the art (I) IR movement tracking In-room CT on rails e - -linac MV cone beam CT kv X-ray position control, flouroscopy Radiotherapy department," University hospital Dresden" D.A. Jaffray et al.: IJROBP 53 (2002) 1337"

6 1. In-room imaging: state of the art Electron linacs state of the art (II) Projection radiography Projection radiography Calculation of " displacement vector" Patient position correction Robotic patient couch advantageous Application of fiducial markers " Digitally reconstructed radiographs from treatment planning CT "

7 1. In-room imaging: state of the art Electron linacs: Integration of CT, helical tomotherapy Treatment planning kv CT" Daily position verification MV CT" T.R. Mackie et al.: IJROBP 56 (2003) 89,

8 1. In-room imaging: state of the art Error sensitivity of particle therapy: the finite range Bronchial-carcinoma, 1 H, MGH Boston" Planning CT" Chordoma, 12 C, GSI Darmstadt" Planning CT" Underdosage in the tumour" CT after 5 w. RT" Overdosage in normal tissue" CT after 2 w. RT" T. Bortfeld, MGH, AAPM 2009 W. Enghardt et al.: Radiother. Oncol 73 (2004) S96

9 1. In-room imaging: state of the art Particle facilities MV cone beam CT kv cone beam CT kv X-ray planar imaging IR movement tracking Stereoscopic movement tracking In-room CT on rails Orthogonal planar X-ray imaging"

10 2. Particle beams: Nuclear methods PT-PET: Overview Projectile Projectile fragment Fireball Nucleons and clusters Radioactive nuclides Target Target fragment In-beam: GSI Darmstadt" Off-line: MGH Boston, HIT Heidelberg" " " Prompt γ-rays More:" Univ. of Florida" HIMAC, Chiba, J" NCC, Kashiwa, J " HIBMC, Hyogo, J" MDACC, Houston" Technology: solved" Research: " Clinical application" Moving targets" J. Pawelke et al.: PMB 41 (1996) 279, W. Enghardt et al.: NIM A525 (2004) 284, K. Parodi et al.: IJROBP 68 (2007) 920

11 2. Particle beams: Nuclear methods PT-PET: Workflow and potential Monte Carlo" Dose" Irradiation and PET" β + -activity" Evaluation and reaction" β + -activity" J! In-vivo range measurement" Dose" L! In-vivo dosimetry" Real time image guidance" W. Enghardt et al.: Radiother. Oncol. 73 (2004) S96"

12 2. Particle beams: Nuclear methods PT-PET: Technical solutions 0.66 Gy 0.37 Gy PET G. Shakirin: et al. Phys. Med. Biol. 56 (2011) 1281 " PET/CT

13 T. Nishio et al.: Med. Phys. 33 (2006) 4190 K. Parodi et al.: NIM A 545 (2005) 446, P. Crespo et al.: IEEE TNS 52 (2005) 980" 2. Particle beams: Nuclear methods In-room PET (National Cancer Center, Kashiwa, Japan) IBA proton therapy unit (cyclotron)" BOLPs (Beam ON-LINE PET system)" Why in-room and not in-beam?" DAQ: 200 s after irradiation" Cyclotron: CW accelerator" In-beam PET at CW accelerators???" Beam on" True coincidences from β + -decay: " used for reconstruction" Beam off" - Double head (12 19 cm 2 ) " BGO crystals" - Crystal size: mm 3" Mainly random coincidences from γ-ray background " during beam extraction: rejected from reconstruction"

14 2. Particle beams: Nuclear methods Off-line PET/CT (HIT Heidelberg) Shuttle compatible with tables from PET/CT and treatment room Workflow Pre-TX control-ct " Irradiation " Post-TX PETCT without changing the patient fixation (beneficial for complex extracranial sites) S. Combs et al.: Nuklearmedizin 2011; K. Parodi et al.: IEEE CR 2011 "

15 2. Particle beams: Nuclear methods In-room PET (OncoRay Dresden) Jan. 20, 2012"

16 2. Particle beams: Nuclear methods Beyond state of the art: In-beam SPECT Projectile Projectile fragment Nucleons and clusters Fireball Radioactive nuclides Prompt γ-rays Target fragment Emission of γ-rays" Monte-Carlo simulation" of irradiation" and measurement Proton treatment plan" Brain tumour" CMS TPS (Elekta)" AKH and Med. Univ. Vienna" Target A. Müller, Diploma thesis, TU Dresden, 2011"

17 2. Particle beams: Nuclear methods In-beam SPECT: Physical conditions Emission of γ-rays " photons / fraction (2 Gy)" photon energy: 0 >10 MeV" J! L! Photons / (MeV p) -1 " E p = MeV" 99m Tc: 140 kev, Anger-camera " Energy / MeV" A. Müller, Diploma thesis, TU Dresden, 2011" Photo: Siemens AG" Compton-" camera"

18 2. Particle beams: Nuclear methods Gamma-ray based range measurements First results with passive slit collimation (10 cm lead or tungsten collimators)" TOF background" discrimination" 75, 95 AMeV 12 C-ions on PMMA" 160 MeV protons on PMMA" ENVISION collaboration: D. Dauvergne et al. (IPN Lyon), D. Prieels et al. (IBA)"

19 3. Magnetic resonance imaging and RT Basics MRI:" does not deposit any additional dose" allows for permanent imaging during an entire treatment fraction" offers superior soft tissue contrast" J! allows for real time image guidance and in-vivo 3D motion tracking " at a 1 s time scale (even at 1.5 T)" influences the primary beam" influences the secondary electrons and thus dose deposition " (esp. at high density gradients, but not for protons) " L! is expensive" Crijns et al.: PMB 56 (2011); St. Aubin et al.: MP 37 (2010); Bielajew: MP 20 (1993); Raaymakers et al.: PMB 53 (2008)

20 3. Magnetic resonance imaging and RT Real-time MRI Courtesy: N. Abolmaali, OncoRay Dresden

21 3. Magnetic resonance imaging and PT MRI combined with an electron linac: The Utrecht * approach Clinical accelerator design" Laboratory setup" *" University Medical Center, Utrecht, NL" Philips Research, Hamburg, GER" Elekta Oncology Systems, Crawley, UK" RaySearch Laboratories, Stockholm, S" B.W.Raaymakers et al.: PMB 56 (2011) N207; B.W.Raaymakers et al.: PMB 54 (2009) N229

22 3. Magnetic resonance imaging and PT MRI combined with an electron linac: The Edmonton * approach *" Department of Physics, " University of Alberta," Edmonton, Canada" " Department of Oncology, " Medical Physics Division, " University of Alberta" Edmonton, Canada" " Department of Medical Physics, " Cross Cancer Institute, " Edmonton, Canada" Linac on," beam off," SNR = 80" Linac on," beam on," outs. acqu." window," SNR = 61" Linac on" beam on," inss. acqu." window," SNR = 16" B. G. Fallone et al.: Med. Phys. 36 (2009) 2084

23 3. Magnetic resonance imaging and RT MRI combined with an 60 Co source: The ViewRay* approach Prostate: 71 beams, dose distributions" 6 MV " 60 Co" Relative dose" Prostate, DVH: " 7 equidistant beams, " PTV1" PTV2" Rectum/Anus" Urinary bladder" Skin" 6 MV" 60 Co" Lateral distance / mm " ViewRay, Inc. Gainsville. FL, C. Fox et al.: Phys. Med. Biol. 53 (2008) 3175

24 Conclusions 1. In-room imaging is at high level at conventional photon beams" " integrated technology up to real time imaging" " peripheral technology of high image quality" 2. In-room imaging at particle therapy units has to be brought " above this level" 3. Nuclear methods offer additional potential for particle therapy" (e.g. in-vivo range measurements)" 4. MRI may have the potential to become the base for a " real-time adaptive radiotherapy"

25 1. In-room imaging: state of the art The radiotherapeutic window H. Holthusen, 1936:" Chose D( r ) such that" the tumour will be destroyed" the surrounding normal tissue " will be saved" CFSP = TCP (1 - NTCP)" CFSP: "Complication free survival probability" TCP: "Tumour control " probability" NTCP: "Normal tissue " complication probability" TCP! NTCP 1! NTCP 2! Tumour:" Dose"! RBE " " - Steep dose gradients (IMRT, protons, ions)" - Selective RBE (ions)" - Reduced treatment margins" Normal tissue:" Dose"! RBE " " Challenge: precise positioning over ~ 30 daily fractions"

26 3. Magnetic resonance imaging and RT X-ray imaging for IGRT: a radioprotection problem? Considering X-ray IGRT dose:" " " - Leakage and Scatter from an e-linac:" " NCRP 102 (1989): The absorbed dose rate due to leakage radiation " " " " excluding neutrons at any point outside the maximum " " " sized useful beam at the normal treatment distance shall " " " not exceed 0.2 % of the absorbed dose rate on the " " " " central axis at the treatment distance. " " D =60 Gy, D leakage < 120 mgy" - Therapy supporting X-ray imaging (aggresive):" " EPID: D = mgy/image" " 30 fractions: daily AP, lateral EPID: D total = Gy" " CT: D = mgy/scan" " 30 fractions: daily scan: D total = Gy" " M.J. Murphy et al.: Report of the AAPM Task Group 75Med. Phys. 34 (2007) 4041"

27 4. Magnetic resonance imaging and PT MRI combined with an electron linac: The Edmonton * approach *" Department of Physics, " University of Alberta," Edmonton, Canada" " Department of Oncology, " Medical Physics Division, " University of Alberta" Edmonton, Canada" " Department of Medical Physics, " Cross Cancer Institute, " Edmonton, Canada" J. St. Aubin et al.: Med. Phys. 37 (2010) 4916

28 3. Particle radiography Transmission ion imaging prior to or in-between RT Proof-of-principle of 12 C Heavy Ion Radiography and Tomography 12 C ions Radiography X-rays 12 C ions Water equivalent thickness Tomography X-rays Water equivalent pathlength D ion << D X-ray E ion >> E ion (R = 30 cm)! I. Rinaldi: Ph.D. Thesis, Univ. Heidelberg, 2011; I. Rinaldi, et al.: 3 Ländertagung der ÖGMP, DGMP und SGSM, Wien, Sept. 2011