PhD student develops radiotherapy monitor using glass jewellery beads
Medical physics PhD student Shakardokht Jafari has developed a way of monitoring radiotherapy doses using inexpensive glass jewellery beads, opening up new possibilities for cancer treatment around the world.
Source: Surrey University
In Shakardokht’s home country of Afghanistan there has been no radiotherapy treatment available since before the war, meaning that cancer patients face a poor prognosis if they cannot afford to travel to neighbouring countries and pay for treatment.
Seeing her own father die prematurely from cancer prompted medical physicist Shakardokht to specialise in the area of dosimetry – the monitoring of radiotherapy exposure – in order to do something about cancer care in Afghanistan. Currently studying for a PhD in radiation dosimetry at the University of Surrey, Shakardokht has also become a member of the Afghanistan Atomic Energy Commission and an advisor on radiation in her country.
Based in the University’s Center for Nuclear and Radiation Physics, Shakardokht’s research project has been to find an alternative to commonly-used dosimeters, overcoming both their high cost and many other limitations. Using Professor David Bradley’s research into optical fibres in dosimetry as a starting point, she began to consider other forms of glass that are robust and offer good spatial resolution in three dimensions, rather than using glass fibres, which are too fragile for practical use and can only be used to measure radiation in one dimension.
“When I was a child, I used to make necklaces using glass beads to earn a little money,” she says. “This gave me the initial idea of using these cheap beads as TL (thermoluminescent) dosimeters.” Putting her theory to the test, Shakardokht found that not only are glass beads far less expensive than traditional dosimeters – costing mere pennies instead of £30 – they also offered a far better performance across a range of parameters.
Radiotherapy aims to achieve optimal tumour control with minimal damage of normal tissue. Recent developments in radiotherapy demand radiation detectors of very small sizes with high accuracy and precision, but most detectors fall short of this because they are unable to pinpoint the tumour area accurately, or because their measurement is affected by a number of factors such as low dose rate or radiation direction. Shakardokht found that the glass beads enabled a higher level of accuracy, with less variation of results caused by external factors, and a better linear response over a wide dynamic range.
She also found that the light sensitivity of beads – which could potentially cause the radiation dosage to be overestimated – was drastically reduced by storing them in the dark following an initial baking process. Measured by a TLD reader commonly used in most hospitals, the glass beads also have a “fading rate” (whereby the measurement information is lost) of only 10% compared to between 25% and 60% for other materials.
While Shakardokht’s radiotherapy solution has many potential uses, such as measuring radiation following a nuclear accident or in industry, healthcare is the area where she believes it could change lives most significantly. She presented her research paper on 22nd June at the First International Conference on Dosimetry and its Applications in Prague.
“It went very well and many people were interested in my work and some of them said they were inspired. I was the first scientist from Afghanistan participating in this type of conference and showing the other face of Afghanistan to people rather than just war”, said Jafari.