IGRT – Just a Buzz
Transcription
IGRT – Just a Buzz
IGRT – Just a Buzz-Word ? 5th Langendorff – Symposium, 26‐27 April, Freiburg Fridtjof Nüsslin Klinik für Strahlentherapie und Radiologische Onkologie Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Scope • Introduction • History & Definition of IGRT • Rationale of IGRT • • Quality of Treatment Delivery Reduction of Treatment Toxicity • Technologies • EPID, CBCT, MR-Linac • Critiques • • • • Clinical relevance Radiation Risk Assessment Costs: investment versus outcome Global view: impact on cancer care • Conclusion Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Introduction History and Definition of IGRT Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie The more than 10 year history of IGRT a c Canada Post Corporation (1988) Cobalt Therapy, 1951, Johns , Cunningham, Holloway b a) 60Co treatment head, (b) a small 120kV diagnostic X‐ray unit, (c) an image intensifier coupled to a vidicon camera, and (d) a counterweight, that also acts as a protection shield. Ionisation chambers are built‐in the counterweight, allowing transit dosimetry. Dr. H. Lokkerbol, NKI in the Netherlands, implemented clinically in 1961. A (short) history of image‐guided radiotherapy, Verellen et al, RTO 86 (2008) Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Imaging in Clinical Oncology Localisation/ Treatment Planning Diagnosis Treatment Delivery Treatment Response, Follow‐up Portal Film Ultrasound Convent. X‐ray CT MR, fMR, MRS PET‐CT, MR‐PET Radioisotopes/ SPECT, PET Image Guided Radiotherapy EPID Helical CBCT IGRT: imaging in the treatment room prior or during treatment delivery • to allow for proper adjustment based on acquired images, • to decrease PTV to CTV margin Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie “I can´t hit what I can´t see, I can´t cure what I can´t hit“ Harold Johns 1915-1998 For a long time RT Technology Development was following the inverse Path: Guidance by intuition instead imaging Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Rationale of IGRT • Quality of treatment delivery – To deliver the treatment as prescribed – To measure the radiotherapy delivery performance • Biological relevant dose optimization – Reduction of toxicity – Dose escalation approach – Hypofractionation – Adaption of treatment (multi‐modality therapy) Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie IGRT: Quality of Treatment Delivery • To deliver the treatment as prescribed • • • • • Reducing geometric uncertainties Eliminating systematic errors Verifying / correcting patient set-up & beam positioning Intra-fraction motion management (4D-Image acquisition, gating, tracking) Adapting margins and treatment plan during the course of treatment • To measure the radiotherapy delivery performance • • • • Analysis of image data Exit dose evaluation Model based dose calculation algorithms TCP & NTCP assessment Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Patient positioning - set up errors & CBCT frequency none First five days daily CBCT – cone beam CT ML – medio‐lateral (L‐R) Image guidance in lung cancer radiotherapy Higgins et al 2011 Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie IGRT: Reduction of Treatment Toxicity • To reduce the PTV margin around the CTV • To allow for high conformal treatment techniques with steep dose gradients (3D-CRT, SRT, IMRT, pRT) • To prevent exceeding critical organ dose threshold Clinical Impact ‐ Examples: 50% reduction in genitourinary toxicity and improved biochemical control in high‐risk patients when applying IGRT. Zelefsky et al, 3.5 cm PTV Ø 4 cm IROBP 84 (2012) 22.5 cm3 V 33.5 cm3 • Superiority of IG‐CRT (equivalent to BRT and Reducing the margin from 10 mm Surgery) over standard RT of prostate ca. to 5 mm saves 50% of the PTV Kupelian et al. IROBP 58 (2004) (CTV diameter 3cm) • At 24 months, no significant differences were seen between randomised groups in non‐xerostomia late toxicities, locoregional control, or overall survival. 47 patients were assigned to each treatment arm. Median follow‐up was 44∙0 months (IQR 30∙0–59∙7). At 12 months xerostomia side‐ effects were reported in 73 of 82 alive patients; grade 2 or worse xerostomia at 12 months was significantly lower in the IMRT group than in the conventional radiotherapy group. Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Technologies EPID, CBCT, MR-Linac, Innovations Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie IGRT Solutions: Radiographic imaging • Planar Systems (Portal film • Digital Systems (EPID) • kV‐/ MV‐Systems (CBCT, Helical) • Ultrasound • new horizons Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie MRI-guided RT ELEKTA/PHILIPS: The MRI‐linac Rotating gantry with 3 Cobalt‐60 teletherapy heads and 3 combines a 1.5 T MRI scanner and a MLCs. Split‐magnet MRI system for volumetric and multi‐ 6 MV linear accelerator. planar soft‐tissue imaging. (VIEWRAY) Cross Cancer Institute, Edmonton, B.G.Fallone (2012) The Cross Cancer Institute is investigating two linac‐MR designs: a longitudinal configuration (left) and a transverse configuration (right). The team is installing both configurations to confirm the dosimetric differences between the two. Image courtesy of the Cross Cancer Institute. 6 MV Linac 0.6T & SC‐MRI Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Innovative Solution from SALK: Robotic Positioning & Imaging System PAIR = Patient Alignment Imaging Ring PAIR = treatment unit + positioning/imaging unit Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Some critical remarks …. Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Yes, IGRT is more than just a buzz word, but ……. Risk ‐ Benefit Quality Assurance Health Care Costs Global Perspective Technology Obsession Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie IGRT – what is the real benefit? • How translates improving treatment deliver quality into better outcome? • Outcome assessment by clinical trials; • • • Short term: set-up uncertainties & reduction of motion artifacts Appropriate time pattern Influence of tumor site and IGRT method • Conventional fractionation and PTV concept adequate? • Re-visiting the conventional target volume concept (GTV-CTV-ITV-PTV): IGTV or PTVIG (C.Ling,2006) • IGRT&IMRT: Re-visiting 2Gy-fractionation RT, hypo- or single fraction RT Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie D95% GTV Fractionation D95% PTV Does IGRT ensure target dose coverage of head and neck IMRT patients? (P.Graff et al., RTO 2012) Comparisons of MVCBCT‐generated dosimetric data (patient 1 as an example). Dosimetric index variations (DVH data); top: GTV; center: hPTV; bottom: spinal cord. Fractionation D95% Spine Fractionation Conclusion: The dosimetric impact of anatomic changes during RT is of lesser importance than the effects of IGRT repositioning. Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie IGRT in Brachytherapy (Interventional RT) „Brachytherapy well acknowledged for all its inherent physical & biological advantages, carrying the paradigm of basic physical superiority to external beam photon radiotherapy: High tumour dose with normal tissue sparing at the same time“ R.Pötter, RTO 2009 Technological Progress Advanced imaging, computer, application & delivery technology • • • • • Transrectal ultrasonography (Holm et al, 1983) Imaging before, during and after BT (CT, MRI) Image based on-line treatment planning Afterloading developments Cost efficiency Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Radiation dose associated with radiological IGRT techniques Orthogonal kV-imaging: Helical kV-CT Helical MV-CT kV-CBCT MV-CBCT < 1 mGy 10-15 mGy/Scan 10-20 mGy 10-30 mGy 80-100 mGy Additional radiation exposure of PTV may be neglected, however, peripheral dose has to be considered (depending on the acquisition protocol). SSK Empfehlungen, 2010 Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Data Handling & Storage Typical responses to IGRT data storage requirements: • • • • „that is a lot more than we are used to“ „where do I put this data? „how can one move large data volumes to where it is needed? „what is it going to cost?“ Problems: • Storage Requirement • Archive • Communication • Workflow • Hardware Infrastructure • Staff, Maintenance Rough Estimate: Facility treating 2000 pts with 30 fx & daily IGRT require 1TB/y SJ Swerdloff (2007) Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie Total costs of Cancer Care • Cancer Care Costs per total health costs (2004‐2010) – Europe: 4.1% (NL) to 7% (S) – USA: 5% – Japan: 9.3% • Rate of increase in health care spending (USA): – 5% of GDP in 1965 to 20% in 2020 • Cost of imaging for cancer: 5.1% to 10.3% /year during 1999‐2006 in USA 05.06.2013 Fusszeile 23 Commission, 2011 The Lancet Oncology Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie BCSoMD Medical Equipment Results: Radiotherapy Availability 30%of cancers could be prevented Approximately 70% of cancer deaths occur in low‐ and middle‐ income countries 36% of the world do not have at least 1 Radiotherapy unit per 2 million population, 81% of them from low and lower‐middle income countries Adapted from WHO, 2012 Future • Smarter Systems • Software tools for image analysis • Balanced Technology Development • Outcome Assessment (clinical trials) • Cost efficiency Conclusion • The new frontier is individualized medicine, IGRT which aims to tailor the treatment to the patient is the response of radiotherapy to this approach. • IGRT is expected to provide a more successful, less toxic and more cost‐effective treatment. • IGRT challenges for clinical evaluation and technical innovation Thank you