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Treatment planning in hadrontherapy. Faiza Bourhaleb TERA Fondation Dipartimento di Fisica sperimentale University Med 1er-Morocco (Faculté des Sciences). Radiotherapy Optimization techniques Hadrontherapy Treatment planning ANCOD++ Perspectives. Oujda -11- May 2002. Acknowledgment.
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Treatment planning in hadrontherapy Faiza BourhalebTERA Fondation Dipartimento di Fisica sperimentaleUniversity Med 1er-Morocco(Faculté des Sciences) • Radiotherapy • Optimization techniques • Hadrontherapy • Treatment planning • ANCOD++ • Perspectives Oujda -11- May 2002
Acknowledgment Mohamed Belmostafa Alberto Boriano Faiza Bourhaleb Roberto Cirio Jamal Derkaoui Marco Donetti Flavio Marchetto Cristiana Peroni Camilo Sanz Freire
Radiotherapy, the history: • RT as an inter-disciplinary technique. • Conventional RT !!??No: Too many error sources due to • a large rectangularly shaped fields • bad definition of target volume to irradiate. • Since 1973, conformational RT=>definition. • The Intensity Modulated RT => MLC What is a treatment plan and what is to plan a treatment?
Optimization and treatment planning • Patient steps before treatment • CT and 3D definition of the global volume for treatment. • Doctors prescription. • Planning of the treatment. • Optimizing a TP • Forward planning (experience!?) • Monte Carlo simulation (Time!?) • Inverse planning and 3D optimization • ANCOD++ !??
Why we should think of new technique!!! (random attempts,waste of time) • The solution is an inverse planning, and what about optimization of beam parameters? • The beam intensity is the most important free parameter.
Help from mathematics and numerical calculation • Big variety of algorithm already exiting: • Inverse planning: • Conjugate Gradient minimization. • Quasi Newton minimization. • Simulated annealing minimization. to resolve a ‘simple’ linear system:
Particularities of hadrontherapy. • Physical properties of protons and carbon ions • Macroscopic feature: Protons and light ions allow truly conformal radiotherapy with millimetric precision.
Biological properties • Double strand break • Lethal events Alpha particles Carbon ions
Relative Biological Efficiency: It shows that to obtain the same biological effect mush less physical dose is required.
Treatment planning in hadrontherapy. • Patient information: • Anatomy • CT images for treatment • Doctors prescriptions considering devices limitations for the treatment. • Optimization technique: • Mathematic algorithm • 2D or 3D optimization! • Display of final 3D dose distribution and notion of DVH =>Evaluation of the 3D optimization!
ANCOD++(Analytical CODe) description VOXEL CT Target Accelerator Field Energy Optimize Dose
ANCOD++, results Dose 100 40 X
DVH inside target • DVH outside target • What about the comparison with IMRT? Volume% Dose%
Comparison: IMRT Protons Between eyes Abdomen Brain
ANCOD++ and GEANT3 simulation • ANCOD++ • GEANT 3
The future !!?? Hadrontherapy has a big chance to be the therapy of the future since it has minimum possible side effects, sparing as no other technique can do the organs at risk. It adopts the newest techniques of treatment planning, optimizing time and in that way money also. It is now a technique a bit expensive comparing with therapies with photon or electrons but like all the new technologies at the beginning they are too expensive but then the expenses decrease quickly with time.
Revolution and era of Conformational RT: (fitting and modeling the irradiating field to the target form) • Blocks • Filters • Wedges • Compensators • Collimators….. scatterer Ridge filter Filter degrader Ridge filter Bolus First collimator Bolus Final collimator Final collimator Body Cancer
The IMRT birth => MLC. • Gantry with an DMLC • The Multivane Intensity modulating Collimator (MIMIC).
Iterative method used in our software. Dose required in a specific voxel is changed at each iteration for the new one with correction. We start consideringonly the weight due to the beamsteered in such a way to have the Bragg peak on the actual voxelthus corresponding to the maximum of energy deposition. At the next iteration the dose is then readjusted to account forthe dose deposited in a given voxel when the irradiation ofthe other voxels occur.