Topic -Analysis of Patients specific Quality Assurance of IMRT/VMAT
G If Mi2010 No Animations
1. Assuring safety in radiation treatments of cancer by use of quantitative MRI. Jan Vandecasteeleand Yves De Deene Ghent Institute for Functional and Metabolic Imaging (GIfMI) Symposium, October 1st 2010
10. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY Linear accelerator Multileave collimator 6-25MV photon beam tailored to the shape of the tumour
11. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY Complex Treatment chain Machine QA Machine modeling CT/MRI/PET image merging Target and OAR delineation Treatment optimization Dose calculation Data transfer Clinical diagnosis Treatment planning PET CT MRI acquisition Machine QA Machine QA Treatment Simulation
12. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY Things seems to go wrong… Routine survey of radiation therapy centers in the US shows that 1/3 of the centers fail the target criteria OAR PTV Spinal cord PLAN Measurement Radiologic Physics Center study 2008
13. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY 3D dosimetry mimics the patients treatment Patient diagnosis Gel fabrication CT scan Identical steps as patient treatments Treatment planning Irradiation Patientfollow up qMRI scanning Post processing
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15. fitting the intensity of consecutive base images to monoexponential decay using X² minimalisation (based on Levenberg-Marquardt algoritm) 4. QMRI SCAN Dose map in 3 dimensions R2-map 5. POST PROCESSING
16. MSAT Freq. encoding Phase encoding W0 f [Hz] Slice selective spoiler gradients RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY CURRENT PROJECTS : Lung equivalent gel: MT imaging Radiation sensitive foam off-resonance radio-frequency pulses ? D [Gy] Microscopicpicture Micro-CT image Liquid H-pool S saturation rf - pulse MMT + Mdir Water polymer H-pool Magnetization is continuously transferred between H protons of water and H-protons on the polymers Saturation of the polymer using off resonance RF pulses prior to SE read out leads to contrast that is dependent on the absorbed dose Fast relaxating insoluble polymer De Deene et al, Med. Phys. 33: 2586-97, 2006
17. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY CURRENT PROJECTS: Clinicaldoseverifications IMRT treatment plan for an oropharynx cT3cN2aM0 Oropharynx (cT3cN2aM0) PTV_69 -> main plan mandible superior Pharyngeal constrictor TP parotis gland Gel Axial Sagital Coronal PTV_40 -> boost plan spinal cord
18. 150 MU 375 MU RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY 60° CURRENT PROJECTS: Accuracy and precisionstudy -60° 8 180° 525 MU Intra-batch reproducibility Inter-batch reproducibility Positional and dosimetric accuracy
23. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY CURRENT PROJECTS: Alternativeread-outtechniques: Optical CT
24. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY CURRENT PROJECTS: Alternativeread-outtechniques: Optical CT
25. RESEARCH GROUP QUANTITATIVE MRI IN MEDICINE AND BIOLOGY Work in progress: Non-toxic gel dosimeters Improve user friendliness Improve accuracy and precision Comparison MRI versus Optical CT Large-scale multicenter clinical validation study of 3D dosimetry 4D gel dosimtery
26. Assuring safety in radiation treatments of cancer by use of quantitative MRI. Jan Vandecasteeleand Yves De Deene Ghent Institute for Functional and Metabolic Imaging (GIfMI) Symposium, October 1st 2010
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