Detector technologies: from particle physics to radiotherapy

1. Detector technologies: from particle physics to radiotherapy B. Camanzi STFC – RAL & University of Oxford

2. Outline • Why cancer • The detector challenges: dosimetry and imaging • Positron Emission Tomography (PET) • Time-Of-Flight PET • Future activities • Conclusions SEPnet RDI Kick-off Meeting 19/04/10

3. The challenge of cancer in UK • Cancer is the leading cause of mortality in people under the age of 75. 1 in 4 people die of cancer overall. • 293k people/year diagnosed with cancer, 155k people/year die from cancer. • Incidence of cancer is rising due to: • Population ageing • Rise in obesity levels • Change in lifestyle • Cancer 3rd largest NHS disease programme. SEPnet RDI Kick-off Meeting 19/04/10

4. Radiotherapy and cancer in UK • Radiotherapygiven to 1/3 of cancer patients (10-15% of all population). • Overall cure rate = 40%. In some instances 90-95% (for ex. breast and stage 1 larynx cancers). • Radiotherapy often combined with other cancer treatments: • Surgery • Chemotherapy • Hormone treatments SEPnet RDI Kick-off Meeting 19/04/10

5. Radiotherapy treatments • External beam radiotherapy: • X-ray beam • Electron beam • Proton/light ion beam • Internal radiotherapy: • Sealed sources (brachytherapy) • Radiopharmaceuticals • Binary radiotherapy: • Boron Neutron Capture Therapy (BNCT) • Photon Capture Therapy (PCT) SEPnet RDI Kick-off Meeting 19/04/10

6. The technological challenges • The challenge of radiotherapy from the patient end Make sure that the right dose is delivered at the right place = improved dosimetry + improved imaging • The challenge of early diagnosis “See” smaller tumours = improved imaging • New advanced technologies desperately needed for dosimetry and imaging SEPnet RDI Kick-off Meeting 19/04/10

7. How particle physics can help "The significant advances achieved during the last decades in material properties, detector characteristics and high-quality electronic system played an ever-expanding role in different areas of science, such as high energy, nuclear physics and astrophysics. And had a reflective impact on the development and rapid progress of radiation detector technologies used in medical imaging." “The requirements imposed by basic research in particle physics are pushing the limits of detector performance in many regards, the new challenging concepts born out in detector physics are outstanding and the technological advances driven by microelectronics and Moore's law promise an even more complex and sophisticated future.” D. G. Darambara "State-of-the-art radiation detectors for medical imaging: demands and trends" Nucl. Inst. And Meth. A 569 (2006) 153-158 SEPnet RDI Kick-off Meeting 19/04/10

8. In-vivo dosimetry • Radiation sensitive MOSFET transistors (RadFETs) used in particle physics experiments (BaBar, LHC, etc.) for real-time, online radiation monitoring. • Development of RadFET based miniaturised wireless dosimetry systems to be implanted in patient body at tumour site for real-time, online, in-vivo dosimetry. SEPnet RDI Kick-off Meeting 19/04/10

9. Gamma camera (SPECT) CT scanner Scintillator Diode Collimator Courtesy Mike Partridge (RMH/ICR) Imaging • Most medical imaging systems, CT, gamma cameras, SPECT, PET, use particle physics technologies: scintillating materials, photon detectors, CCDs, etc. SEPnet RDI Kick-off Meeting 19/04/10

10. 511 keV g 511 keV g Courtesy Mike Partridge (RMH/ICR) Positron Emission Tomography • 18F labelled glucose given to patients: e+ annihilates in two back-to-back 511 keV g. • A ring of scintillating crystals and PMTs detects the g. SEPnet RDI Kick-off Meeting 19/04/10

11. Courtesy Mike Partridge (RMH/ICR) PET CT PET + CT Conventional PET Conventional PET scanner: • Coincidences formed within a very short time window • Straight line-of-response reconstructed • Position of annihilation calculated probabilistically SEPnet RDI Kick-off Meeting 19/04/10

12. Time-Of-Flight PET (TOF-PET) • TOF-PET scanner: • Time difference between signals from two crystals measured • Annihilation point along line-of-response directly calculated • Goal: 100 ps timing resolution (ideally 30 ps and below) = 3 cm spatial resolution (ideally sub-cm) • Advantages: higher sensitivity and specificity, improved S/N • Technology needed: fast scintillating materials and fast photon detectors SEPnet RDI Kick-off Meeting 19/04/10

13. Fast scintillating materials BrilLanCeTM380 and PreLudeTM420 produced by Saint-Gobain Cristaux et Detecteurs SEPnet RDI Kick-off Meeting 19/04/10

14. 1x1 mm2 3x3 mm2 Hamamatsu Inc. Photon detectors: SiPMs • Array of Silicon Photodiodes on common substrate each operating in Geiger mode • SiPMs have speed (sub ns) and high gain (106), small size and work in high magnetic fields (7T) SEPnet RDI Kick-off Meeting 19/04/10

15. Tests on TOF-PET prototypes • LaBr3(Ce) and LYSO scintillating crystals from Saint-Gobain • SiPMs from Hamamatsu, SensL and Photonique • Various two-channel demonstrator systems tested at RAL and RMH • Timing resolution analysis still ongoing SEPnet RDI Kick-off Meeting 19/04/10

16. Preliminary results • Best SiPMs: Hamamatsu (electrical problem with 11-25) and SensL. • Best timing resolutions measured: • 20 ps for single SiPM • 40 ps for pairs of SiPMs • Hamamatsu performance as function of pitch still under investigation. • Prototypes with Hamamatsu 3x3 mm2 best of all. SensL blind to LaBr3. • Best timing resolutions measured: • 430 ps with 3x3x10 mm3 LYSO • 790 ps with 3x3x30 mm3 LaBr3 • Performance of prototypes with LaBr3 highly dependent from SiPM-crystal coupling. SEPnet RDI Kick-off Meeting 19/04/10

17. Where next • Preliminary results very encouraging. Need to investigate technology further: build a dual-head demonstrator system. Two planar heads with identical number of channels. • Use of fast scintillators can be expanded to other imaging systems (CT, SPECT, etc.). • Use of SiPMs opens up the possibility of designing a compact PET/MRI scanner. SEPnet RDI Kick-off Meeting 19/04/10

18. Future activities • Participation through Oxford to FP7 project ENVISION (European NoVel Imaging Systems for ION therapy). • Development of a technology roadmap for cancer care, to move toward a multi-modality approach to radiotherapy. SEPnet RDI Kick-off Meeting 19/04/10

19. ENVISION • Participation in WP2: development of TOF in-beam PET systems. • Oxford/STFC contributions: • Characterisation of scintillating materials (LYSO and LaBr3) • Characterisation of SiPMs • Construction and test of a TOF-PET dual-head demonstrator system • Simulations of component (crystals and SiPMs) and system performance SEPnet RDI Kick-off Meeting 19/04/10

20. My vision: toward multi-modality • Multi-modality = bringing together the different forms of radiotherapy treatments: • Select best treatment depending on tumour type • Combine different treatments when appropriate • New advanced imaging and dosimetry systems of paramount importance → Technology roadmap • Roadmap to be developed in consultation with end-user groups, universities, etc. SEPnet RDI Kick-off Meeting 19/04/10

21. Conclusions • Cancer is a leading cause of mortality in UK. Its incidence is rising. • Radiotherapy is and will be given to a large number of patients. • Patients will benefit from a multi-modality approach to radiotherapy. This requires the development of new, advanced technologies. • Particle physics holds the key to the development of these technologies. SEPnet RDI Kick-off Meeting 19/04/10

22. Acknowledgements • Prof Ken Peach (John Adams Institute) • Dr Phil Evans and Dr Mike Partridge (Royal Marsden Hospital / Institute of Cancer Research) • Gareth Derbyshire (STFC Healthcare Futures Programme) • Dr John Matheson and Matt Wilson (STFC-RAL) SEPnet RDI Kick-off Meeting 19/04/10