Nanotechnology for enhancing cancer therapy

Charged particle beams can deliver most of their energy to the tumour site

Alumina based detector materials

energy in the range 1000eV to 2000eV "mini e-beams" into the Alumina :e-h production which feeds the detection process

A team based in EEE in collaboration with the School of Materials and the prestigious local Cancer Therapy Centre at the Christie Hospital are using nanotechnology to help solve this problem by exploiting the fact that high atomic number elements can interact strongly with the radiation and hence help the detection process.

This team has developed new alumina based detector materials which contains ultra-small gold clusters. The radiation interaction with the cluster generates energetic electrons which (for small clusters) can escape and transfer the interaction energy to the detector.

Increases in detection sensitivity

Ensemble of 30 electrons produced by X-ray absorption

Large increases in detection sensitivity can be achieved by this method.

The work of this multidisciplinary team is now aimed at optimising such materials and detectors made from them. Such optimisation is being delivered with the help of sophisticated materials modelling based on Mont Carlo modelling of the energy and particle transfer out of the metal clusters. These calculations help us to predict the trajectories and energy loss processes of the fast electrons produced in the detection process.

An example is given here, which (for small clusters) can escape and transfer the interaction energy to the detector.

Radiotherapy treatment

Around 50% of all cancer patients receive radiotherapy as their primary treatment and 50% of patients undergoing surgery receive post-operative radiotherapy as follow up treatment. Radiotherapy is then immensely important in the treatment of this disease.

Probably the most common view of radiotherapy is that it involves irradiation with high energy x ray beams to which malignant tissue is more susceptible: DNA in cancer cells gets broken more frequently than in healthy cells. This is true, but over the last two decades the technology for delivering radiation has improved immensely.

Now x-rays are delivered using multiple beams, varying spatially and temporally in a way which ensures that the exposure at the tumour site is much higher than at surrounding healthy tissue.

New forms of therapy

In the past several years new forms have therapy have emerged which rely not on x-rays (which are photon beams) but on hadrons with ionised protons and also carbon ions being the key examples. These charged particle beams carry to great advantages: they can be electrostatically scanned over then target and they can also be organised to deliver most of their energy to the tumour site.

These technology developments have all led to the delivery of very intense and highly targeted beams and this is true for both photon and hadron technologies. In turn this has led to a pressing need for in vivo sensing technologies which can measure and even image the beam footprint at the tumour site or (equally importantly) at the site of nearby sensitive tissue which needs protection.

There is though a major technological headache in realising such a technology. High energy particles are not easy to detect; after all they do tend to travel long distances in matter without interacting.

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