Transcript Instrumentation for radiotherapy Barbara Camanzi

Instrumentation for medical
physics applications
Barbara Camanzi, PPD/RAL
Instrumentation for radiotherapy
 Imaging: 1. Fast Time Of Flight PET
2. Electron Portal Imaging Devices
 In-vivo dosimetry
 Other non medical activities
 Conclusions

Instrumentation for radiotherapy

UK government is supporting expansion of radiotherapy for cancer treatment.

New advanced instrumentation is needed => plenty of possibilities to apply
particle physics techniques in the field of radiotherapy. Many thanks to RM/ICR
colleagues.

Instrumentation => Looking at the treatment from the patient end = to make sure
that the right dose is delivered at the right side (tumour location).

Right location = imaging
P: Better and faster imaging of tumours (organs with high degree of movement)
is needed to precisely located them in respect to the therapeutic beam.
S: Development of a fast Time Of Flight PET.
Development of fast Electron Portal Imaging Devices (EPIDs) with higher
quantum efficiency than ones currently available (few %).

Right dose = dosimetry
P: EU directive for performing online dosimetry measurements for every patient
and every treatment fraction.
S: Development of an online in-vivo dosimetry system.
[email protected]
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Imaging: Fast Time Of Flight PET

Fast high quality imagines to precisely locate the tumour: fast Time Of Flight
PET that achieves sub-cm position resolution (50 ps timing resolution).

Candidate technologies: fast scintillators coupled to SiPMs.
1. Fast and bright scintillators: new lanthanum halide materials by SaintGobain Crystals
2. SiPMs: fast and insensitive to magnetic fields => PET/MRI combined

R&D required:
1. Preparation of scintillating material samples and coupling to SiPM.
2. Measurement of system performance: response time, light yield, energy
resolution.
3. Design and optimisation of a simple demonstrator system: 2 channels.
4. Measurement of performance of demonstrator system: time of flight.

Funds:
1. Just received some CLIK funds (£82.5k) for R&D stages 1. and 2.
2. Another application in with NHS (New and Emerging Applications of
Technology call), outcome by end of May.
[email protected]
3/7
Imaging: Electron Portal Imaging Devices
(EPIDs)

High quality radiography images taken during treatment using therapeutic beam
to centre beam on tumour: fast and high quantum efficiency EPIDs placed
behind patient.
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Candidate technologies: fast scintillators coupled to SiPMs.
1. fast scintillators: lanthanum halides, CsI, etc.
2. SiPMs: multipixels = high spatial resolution

R&D required:
1. Design of an EPID based on scintillators coupled to SiPMs: dimensions,
number of channels, etc.
2. Preparation of the scintillators and SiPMs matrixes and coupling of the
two matrixes.
3. Measurement of the system performance: quantum efficiency, images.

Funds: None yet. Planning to find a suitable funding scheme and apply during
this year.
[email protected]
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In-vivo dosimetry
(See also Giulio Villani presentation)
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In-vivo dosimetry at the tumour site: implantable + intracavitary applications.

Candidate dosimeters: SiO2 devices sensitive to radiation = shift in threshold
voltage following irradiation when biased with constant current.
1. Floating gate devices (see Giulio Villani talk)
2. RadFETs (Radiation sensitive MOSFETs; already used in particle
physics experiments, for ex. BaBar and LHC)

R&D required:
1. Characterisation of dosimeters under irradiation of “therapeutic” beams.
2. Implanted: development of a wireless miniaturised sensor combined with
position sensor.
3. Intracavitary: development of a miniaturised sensor to fit in catheters.
4. Clinical trials.

Funds: some CLIK funds to test floating gate devices (see Giulio Villani talk) and
collaborations with Brunel (Akram Khan + PhD student) and possibly R.E.M.
(Andrew Holmes-Siedle). Possibly look for other funds during this year.
[email protected]
5/7
Other non medical activities

Following invited talk at RADECS 2006, paper on dosimetry for particle
accelerators and nuclear fusion reactors published in May 2008 issue of
Nature Materials. http://www.nature.com/nmat/journal/v7/n5/full/nmat2159.html
[email protected]
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Conclusions

Wealth of exciting projects to further take technologies developed for particle
physics into the medical physics (radiotherapy) world.
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My plans: get for the moment three projects going.
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Potentials in other fields: nuclear fusion.
[email protected]
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