56 lines
No EOL
5.5 KiB
Markdown
56 lines
No EOL
5.5 KiB
Markdown
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- vorher = Status quo
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- RT important
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- promising FLASH
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- not yet in clinical settings ((659b0870-2609-4ae6-ad6f-f179225fb80d))
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- just now first clinical standard?
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- not easy as accelerator based and most clinical linacs not sufficient
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- still much work to be done in metrology(dosimetry and quality control), required for reliability in deposited dose,
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:LOGBOOK:
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CLOCK: [2024-01-07 Sun 21:40:02]
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:END:
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- normal primary standards not directly applicable for short pulses -> UHDpulse project ((659b0cb3-7710-4992-85c4-a42d38baa74f))
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- deviation between measured dose and simulated, ((659b077e-8b51-4d4b-b5f1-35d08f4f33f5))
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- one reason is due to non-linearities in the detector at these ultra-high dose rates (e.g. ion re-combination) in detector) ((659b1b51-bca4-40f3-aa05-fd34eb2af1ba))
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- another reason could be in the simulations of the expected dose, as in nearly all cases one beam-matter interaction is considered but no interaction between the electrons (e.g. BDSIM) ((659b1d67-80a1-4d62-8fa3-99e36c4eb11d))
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- main diagnostic at the moment focuses on does measurements?? very limited beam based diagnostic in medical accelerators used ((659b0db6-1445-4527-b359-a6a6fefc121a))
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- not yet clear what exactly are the optimal parameters when it comes to pulse shortness and high dose ((659b083d-a051-48cf-a962-ad08737f1311)) (see what is possible when considering limitations due to collective effects)
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- current medical accelerators limited to below 20MeV, only allow superficial or shallow tumors, ((659b0b80-3beb-4b61-9f5e-12965650cedb)) -> either got to dedicated linacs or maybe laser driven accelerators? ((659b0bce-2a9f-4f58-9fc3-274297d5c510))
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- and microbeam, mainly with x-ray, as electron beams diverge fast, or with GRID therapy, but similar potential as flash to spare healthy tissue 
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- spatially structured/modulated beams (non-Gaussian) also relevant to accommodate irregular/uneven patient surfaces , very recent patent on passive intensity modulation for electron beams ((659b28fe-16bb-4b12-97e6-eb219198a681)) , 
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- little to no mentioning of consideration of collective effects in the source accelerators, which (from accelerator physics point of view) is expected play an ever increasing role with decreasing pulse length and increasing pulse intensity, as well as with spatial structuring of the beam
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- "OPAL (Object Oriented Particle Accelerator Library) is an open source
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C++ framework for general particle accelerator simulations including 3D
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space charge, short range wake fields and particle matter interaction." (https://gitlab.psi.ch/OPAL)
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- did not find any publication using OPAL for FLASH therapy, found mainly for proton therapy
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- first starting point?
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- --------------
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- I want to investigate how different collective effects known in the accelerator beam dynamics affect the beam transport and beam-matter interaction in novel electron radiotherapy methods, such as FLASH RT, microbeam RT and electron conformal therapy (ECT)
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- to have experimental test bed, use FLUTE for short pulses and spatial light modulator to structure beam, e.g. micro beams, or non-gaussian distribution.....
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- measure dose for different sets, and cross check with improved simulations containing collective effects,
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- also include accelerator diagnostics more into modelling ...
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- how: MC (opal?), covariance matrizes (statistic particle ensemble), phase space density with wake fields, Particle tracking...
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- -----------------------------------
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- result is improved modelling, now including collective effects and that not only in accelerator but also in beam transport trough matter
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- but also knowledge which effects relevant
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- more knowledge about which beam conditions for flash possible to generate with which accelerator parameters/requirements and what diagnostic in accelerator necessary, input for next generation medical accelerators
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- ideally start to end simulation for RT with (temporal and/or spatial) structured beam including collective effects
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- prediction of phase space in target
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- And as a second step, it might allow to consider effects of the beam transport already during the generation of the beam.
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- Aiming towards the generation of a spatial distribution which preemptively compensates for the expected changes, possibly allowing arbitrary user-definable final distributions.
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- --------------------------
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- ???what about some kind of CSR impedance caused by photons emitted when scattered which then hit again other electrons and change energy? does this make sense, as then photon also hit matter, and not very directed so also not very probable to hit other beam electrons, but maybe from transition radiation between dirfferent materials, how is the emission angle from transition radiation? forwards? backwards? both could interact with electrons close by /behind...especially in ultra high density beams... |