One of the most prevalent malignancies worldwide is gastric cancer and by increasing the accuracy of radiotherapy, which is frequently combined with treatment choices like surgery, chemotherapy, or immunotherapy, researchers from the National University of Singapore (NUS) have developed a novel invention that could aid in the improvement of the treatment of this malignancy.
Precision in targeting tumour tissue while minimising damage to healthy tissue is essential in the practice of contemporary radiotherapy. However, due to patient diversity, treatment ambiguity, and variations in delivery forms, low efficacy and varied outcomes continue to be a problem.
Real-time dosage monitoring, particularly in the gastrointestinal system, could improve the accuracy of radiotherapy and increase its efficacy, but it is challenging to implement. Additionally, the current techniques for tracking biochemical parameters like pH and temperature are insufficient for a thorough assessment of radiation.
The research team has created an ingestible X-ray dosimeter that measures radiation exposure in real-time to overcome this difficulty. To determine the amount of radiation absorbed in the target area, clinical dosimeters such as metal-oxide-semiconductor field-effect transistors, thermoluminescence sensors, and optically stimulated films are frequently applied directly to or close to the patient’s skin.
While such dosimetry with electronic portal imaging devices has been considered for treatment verification, these devices can be costly and absorb radiation, reducing the patient’s intended dose. Thus, there is a need for a low-cost swallowable sensor that can measure biochemical markers and X-ray dosage absorption simultaneously during gastrointestinal radiotherapy because ingestible sensors are only capable of measuring pH and pressure.
To overcome these limitations, the research team devised a novel ingestible X-ray dosimeter capsule capable of measuring the radiation dose and physiological changes in pH and temperature in real-time during gastrointestinal radiotherapy.
A flexible optical fibre encapsulated with nano-scintillators that light up in the presence of radiation, a pH-responsive film, a fluidic module with multiple inlets for dynamic gastric fluid sampling, two sensors for dose and pH measurements, a microcontroller circuit board that processes photoelectric signals to be transmitted to a mobile application, and a button-sized silver oxide battery power the capsule.
When the capsule is ingested and reaches the gastrointestinal tract, the nano-scintillators will glow brighter in the presence of increased X-ray radiation; and to determine the amount of radiation given to the targeted area, a sensor within the capsule analyses the brightness of the nano-scintillators.
Additionally, the fluidic module permits the collection of gastric fluid for pH detection using a colour-changing film. Within the capsule, a second sensor detects this change in hue. In addition, the two sensors can detect temperature, which may indicate adverse reactions to radiotherapy, such as allergies.
The photoelectric signals from the two sensors are processed by a microcontroller circuit board, which transmits data to a mobile phone application via Bluetooth technology and an antenna. The mobile app analyses the raw data using a neural network-based regression model to display information such as the radiotherapy dose, temperature, and pH of the tissues undergoing radiotherapy.
Currently designed to monitor radiotherapy doses for gastric cancer, the capsule could also be used to monitor treatment for other malignancies if its dimensions were modified.
The research team is working towards the clinical deployment of their innovation. Classifying the capsule’s position and posture after ingestion, emerging a robust positioning system to anchor the capsule at the intended target site, and further calibrating the accuracy of ingestible dosimeters for safe and effective clinical use are among the next steps in the research process.
