Ultrasonic Sensor-based Water Leveling for Three-dimensional Water Phantom: Prototype Development.

Objectives: The purpose of this study was to develop a prototype for controlling the water level of a three-dimensional (3D) water phantom using ultrasound sensors and Arduino technology and evaluate its performance in setting up the 3D water phantom for radiation beam measurements.

Materials and methods: A prototype consisted of an Arduino Nano board and two types of ultrasound sensors (US015 and SR04). The accuracy of both sensors was tested at various distances and the performance was evaluated through statistical analysis. The distance measurement test was performed rigorously at intervals of 2 cm from 5 cm to 21 cm, measuring an average error and a maximum deviation for each sensor.

Results: Both sensors demonstrated the measurement accuracy within 2 mm. When using the traditional and prototype-based setup methods, the measured photon and electron beam profiles did not show any significant difference. This result suggests the equivalent setup capability when using these two different 3D water phantom setup methods.

Conclusion: The ultrasound sensor-based prototype is demonstrated as a more effective device in maintaining the 3D water phantom setup consistently compared to the traditional method, which is prone to human error, and it will aid in facilitating precise phantom setup during the commissioning and routine quality assurance (QA) of linear accelerators in radiotherapy clinics.