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
Outline 1. In-room imaging: state of the art 2. Particle beams: Nuclear methods 3. Magnetic resonance imaging and radiotherapy
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"
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
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"
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 "
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, www.tomotherapy.com
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
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"
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
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"
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
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 ) " - 40 60 BGO crystals" - Crystal size: 2 2 20 mm 3" Mainly random coincidences from γ-ray background " during beam extraction: rejected from reconstruction"
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 "
2. Particle beams: Nuclear methods In-room PET (OncoRay Dresden) Jan. 20, 2012"
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"
2. Particle beams: Nuclear methods In-beam SPECT: Physical conditions Emission of γ-rays " 4 10 9 photons / fraction (2 Gy)" photon energy: 0 >10 MeV" J! L! Photons / (MeV p) -1 " E p = 82... 135 MeV" 99m Tc: 140 kev, Anger-camera " Energy / MeV" A. Müller, Diploma thesis, TU Dresden, 2011" Photo: Siemens AG" Compton-" camera"
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)"
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)
3. Magnetic resonance imaging and RT Real-time MRI Courtesy: N. Abolmaali, OncoRay Dresden
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
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
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, www.viewray.com C. Fox et al.: Phys. Med. Biol. 53 (2008) 3175
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"
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 " " www.tomotherapy.com" Challenge: precise positioning over ~ 30 daily fractions"
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 = 10-50 mgy/image" " 30 fractions: daily AP, lateral EPID: D total = 0.6 3 Gy" " CT: D = 30-50 mgy/scan" " 30 fractions: daily scan: D total = 0.9 1.5 Gy" " M.J. Murphy et al.: Report of the AAPM Task Group 75Med. Phys. 34 (2007) 4041"
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
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