TINY glass beads placed inside the body could reduce the side-effects that cancer patients experience from radiotherapy.
Dozens of the beads, each less than a millimetre wide, are fed onto a thin cotton thread and inserted into the body through a tube and positioned to sit as close as possible to the tumour.
During each radiotherapy session, the beads soak up radiation.
At the end of each treatment, they are removed and fed through a scanner which measures how much radiation they were exposed to.
This informs doctors whether they're directing the right amount of radiotherapy at the cancer.
If radiation stored in the beads is lower than planned and too weak to wipe out cancerous cells, then the patient's next radiotherapy dose can be increased.
But if the beads show the dose was too high - and in danger of damaging surrounding healthy tissue - it can be lowered.
Around 40 per cent of all cancer patients undergo radiotherapy, which works by killing malignant cells, or by slowing their growth through damage to their DNA.
Typically, a machine beams energy through the skin towards the tumour site. The dose used is altered according to the type of tumour, where it is and its size. Doctors also need to consider how far into the body the energy needs to travel.
But while a machine can be programmed to deliver a specified dose, a difficulty with radiotherapy is determining how much radiation reaches the tumour.
Too little may not get the job done, while too much can worsen side-effects, such as inflammation. Doctors only know if the dose is right when the tumour starts to shrink, or there are obvious signs of harmful side-effects - both of which can take weeks to become evident.
The glass beads could refine the treatment right from the start.
Scientists behind the invention, called DOSEmapper, chose glass because it is able to store electrons, the particles which make up radiotherapy beams.
Once the beads on a string have been fed through the body to the tumour site, they are left in place during the first bout of radiotherapy.
They're then removed and passed through a scanning device, which heats them up to 300C. At that temperature, the beads release the stored electrons in the form of light.
The scanner measures the light to determine how much radiation is in the beads and whether that corresponds to the dose that doctors intended for the tumour.
The results are then fed back to the cancer team, who can adjust the next dose if needs be.
DOSEmapper, which is being trialled at the NHS Clatterbridge Cancer Centre in Liverpool, was developed by Afghan physicist Dr Shakardokht Jafari, after she saw her father die from cancer and developed breast cancer herself.
The researchers say it is most suitable for tumours which can be relatively easily reached with a tube (catheter), feeding it through the mouth, genitals or rectum. But a bead mesh that can be used externally, for example draped over a breast during radiotherapy, is also being developed.
Dr Nicky Thorp, medical director of professional practice and clinical oncology at the Royal College of Radiologists, said: "Radiotherapy is one of the most important tools we have to treat cancer, and it's encouraging to see efforts to make it safer and more effective. We look forward to seeing the results of clinical trials using this technology."
SCIENTISTS in the United States are developing a form of radiotherapy that delivers its dose in less than a second, compared with minutes for conventional radiotherapy.
The technique has been shown to destroy tumours in animals, while significantly reducing the 'collateral damage' to healthy surrounding tissue.
Researchers are fine-tuning the technique at the University of Pennsylvania and plan human trials in the next few years.
© Daily Mail
