IT SYSTEMS, MEDICINE
Smart dosing system for refined cancer treatment
Traditional radiation treatment against cancer, some say, is like using a hammer to fix fine china. Radiation kills the cancer cells, but it knocks out a good deal more than the bad ones. A new sensor system being developed by the EU-backed INVORAD project will help refine this process by boosting radiation dosage accuracy and reliability.
Every year, hundreds of thousands of people are diagnosed with cancer in Europe. Common treatments for this disease are radiotherapy, chemotherapy and surgery. In the UK, for example, of the 200 000 people diagnosed with cancer each year, about half are given radiotherapy to wipe out the disease or alleviate suffering.
|Radiotherapy unit in action.|
© National Physics Laboratory (c/- Philips)
Through intensity-modulated radiotherapy (IMRT), the chances of knocking out cancer are improved because it more accurately targets tumours. It also minimises the amount of potentially harmful radiation absorbed by healthy tissue. But health specialists complain that it is hard to assess the exact dose a patient is receiving. The EU-funded INVORAD project is developing systems that provide real-time monitoring of radiation dosage during cancer treatment.
INVORAD’s project coordinator Aleksandar Jaksic of Ireland’s Tyndall National Institute says that IMRT prescriptions are based on very complex computer simulations. And these simulations must be validated to know exactly how much radiation is reaching the patient and what areas it targets. To do this, INVORAD developed two sensors – a silicon diode and a p-channel metal-oxide semiconductor field-effect transistor (MOSFET).
The diode sensor system is arranged in a series of modules containing 1 069 individual diodes for picking up incoming radiation. These semiconductor sensors are well suited to this job for several reasons, Jaksic notes. They are tiny and respond to different types of radiotherapy. They are also compatible with microprocessors, giving real-time read-outs and cutting costs.
The sensors are extremely accurate and can track radiation at micro-Gray resolution – a very fine reading – over millimetres of spatial resolution. The recorded data is linked to a read-out unit and a PC with specially tailored software. The PC and software provide system control, connectivity to other parts of the total radiotherapy system, and patient-specific data storage.
INVORAD also developed what it calls a cylindrical ‘body phantom’ which works with the diode sensors to control the dose actually delivered. If the ‘phantom’ treatment matches the prescription taken up in the simulator, the dose gets the green light to be delivered to the patient. If not, the treatment plan can be corrected.
“We created modifications on the diodes and diode arrays, improving their specifications for this project. In fact, every element of the project we worked on received some sort of improvement on current systems,” Jaksic told IST Results.
The project’s MOSFET-based device can be mounted on medical catheters which enter the patient through a cavity. This system is being tested on cancer patients in the UK. Of the two devices, the diode system is more commercially viable, once a few modifications are sorted out. But the MOSFET system is working and the results of patient trials will be available in coming months, Jaksic says.
INVORAD is keen to take its devices to market and has lined up ScandiDos, a Swedish start-up, to do just that some time next year, according to IST Results.
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