Smart capsule monitors dose for radiotherapy
“The researchers found that the dosimeter was approximately five times more accurate than standard methods for dose determination,” according to the Chinese Academy of Sciences, whose Shenzhen Institute of Advanced Technology (SIAT) worked with the National University of Singapore and Tsinghua University.
The 18mm long 7mm diameter capsule has an optical fibre encapsulated with X-ray persistent lanthanide-doped nano-scintillators whose glow can be used to estimate radiation dose, and a colour-changing pH-sensitive polyaniline film connected to the gastric fluid by channels in the capsule wall.
Photoelectric signals from the two sensors are processed by a microcontroller circuit board, which sends information via Bluetooth and an antenna to a mobile phone app.
Using a neural network-based regression model, the mobile app processes raw data to display radiotherapy dose, temperature and pH.
“In the future, this capsule could be placed in the rectum for prostate cancer brachytherapy or in the upper nasal cavity for real-time measurement of the absorbed dose in nasopharyngeal carcinoma,” said professor Sheng Zonghai, one of the authors.
The work is described in ‘A swallowable X-ray dosimeter for the real-time monitoring of radiotherapy‘, published in Nature Biomedical engineering.
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