Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Radiation burn wikipedia , lookup
Brachytherapy wikipedia , lookup
Center for Radiological Research wikipedia , lookup
Backscatter X-ray wikipedia , lookup
Radiation therapy wikipedia , lookup
History of radiation therapy wikipedia , lookup
Proton therapy wikipedia , lookup
Radiosurgery wikipedia , lookup
Nuclear medicine wikipedia , lookup
Medical imaging wikipedia , lookup
Cancer Therapy and Imaging Rob Edgecock STFC Rutherford Appleton Laboratory Imaging and Dosimetry • What else do we need to know for radiotherapy? Where the tumour is (exactly) Imaging The structure of the patient Imaging Optimum treatment Treatment planning Correct dose is delivered Dosimetry Imaging • Four main techniques X-rays Imaging • Four main techniques X-rays More absorption by denser objects, e.g. bones - appear lighter Less absorption by less dense objects - appear darker Imaging • Four main techniques CT Scan: Computerised (Axial) Tomography X-rays source and detector rotate Thousands of images taken 3Dish image built by computer Very common technique as very fast Imaging • Four main techniques CT Scan: Computerised (Axial) Tomography Much bigger dose than X-rays! Imaging • Four main techniques Molecular imaging: PET and SPECT Load tumour/organ with radiopharmaceutical. Detect products from decay. Positron Emission Tomography Single Photon Emission Computed Tomography Imaging • Four main techniques PET Scan: Most accurate tumour location Not so good for surroundings Imaging • Four main techniques SPECT: uses a gamma emitter directly Gamma detectors rotate. Make 2D images. 3D reconstructed offline. Resolution not as good as PET. Imaging • Four main techniques MRI Scan: Magnetic Resonance Imaging Magnetic field lines up atoms. Different atoms absorb different RF frequencies. Very good for soft tissues (exploits hydrogen in water). Imaging • Four main techniques are (sort of) complementary • None is ideal • Can lead to incorrectly defined margins Results from 11 student oncologists. Areas inside lines would be treated. Imaging • Situation is improved by combining techniques • E.g. CT + PET • Still significant room for improvement Results from 11 student oncologists. Areas inside lines would be treated. Treatment Planning • Takes images, etc • Uses software to determine best treatment plan • Best position, angle, no. of fields, energies, etc • Depends on image quality, knowledge of tissue, etc • Tumour motion Timescale Effect Possible solution Seconds Breathing Gating; averaging Minutes Patient motion Markers Day Patient position; food & liquid Markers; re-scan Week “ “ “ “ Markers; re-scan • Reduced precision of beam delivery – larger area Dosimetry • Verify correct dose delivered to tumour • ”In-vivo” dosimetry preferred.....but not actually in-vivo! Wireless Catheterdosimeter dosimeter Contributions from Particle Physics • Improved accelerators for radiotherapy hard to improve on linacs for X-rays but.......... Laptop 1MeV electron prototype Big sister being tested Contributions from Particle Physics Fixed Field Alternating Gradient accelerator Synchrotron-like Cyclotron-like • Combines features of cyclotrons and synchrotrons • Interesting for X-ray radiotherapy • But.....particularly interesting for hadron therapy..... • .....plus particle physics, power generation, etc Hadron Therapy • Requirements Proton up to carbon beams; 250 MeV to 400MeV/u Rapid cycling: ~500-1000Hz Rapid energy variation from accelerator Gantries Reliability “Small” cost Small size • Used currently: Cyclotrons: protons; SC understudy for carbon Synchrotrons: protons and carbon Requirements Cyclotron Synchrotron FFAG Yes(ish) Yes Yes Rapid cycling Yes No Yes Variable energy No Yes Yes Cost and size – S/C Yes No Yes Gantries Yes Yes Yes Reliability Yes No(ish) Yes Protons & carbon • FFAGs very interesting • Most interesting type – no machine ever built • So we’ve built one – called EMMA EMMA EMMA = proof-of-principle machine Electrons from 10 to 20MeV Use ALICE as injector 42 magnetic “cells” Built on 7 girders EMMA Works! Full experimental programme started. First results published in Nature Physics. PAMELA PAMELA PAMELA Recondensing cryocooler Insulating vacuum chamber Next step: prototyping of main components: - ring magnets 40k Radiation shield - RF cavities Magnet support structure- extraction magnets Positive funding signs F D F Magnets 40k Inner radiation shield 4k Helium vessel Contributions from Particle Physics • Improved PET imaging: better tumour location verification that treatment in correct place ToF PET • Standard PET: Conventional best tumour locator but essentially 2D Detector software required worse resolution & long time • ToF PET 3D better image & shorter time Tomograph Ring Time-of-Flight ToF PET Phantom (1:2:3 body:liver:tumor) Conventional 1.2 ns 700 ps 500 ps 300 ps • PP techniques being tried • Target ~50ps, but v. difficult Commercially available • Projects to improve other techniques underway Achieved Contributions from Particle Physics • In-vivo dosimetry smaller device - possible to leave in? lower power consumption additional functionality at later date Concept of in-vivo dosimetry Radiation Source PWR UNIT RF UNIT RAD UNIT RF receiver Implantable micro unit Contributions from Particle Physics • In-vivo dosimetry smaller device - possible to leave in? lower power consumption additional functionality at later date Radiation Sensor Antenna Silicon chip Low power electronic Thin film battery on the back side 1000μm Contributions from Particle Physics • Data storage and analysis: creating framework for clinical data including long term follow-up help strengthen case provide info for improvements • Patient modelling no two patients the same treatment planning includes modelling of beam PP techniques and codes being tried PP measurements of interactions for models Conclusions • Knowledge from PP being applied in various areas • Strong priority in the UK • One discussed here • Cancer therapy data storage and analysis modelling detector development accelerator design