Room: Exhibit Hall | Forum 6
Purpose: Three-dimensional motion phantoms are used to simulate and validate internal organ motion in radiation therapy. There are currently no satisfactory motion phantoms that can simulate a high frequency cardiac motion alongside low frequency respirations. The purpose of this work is to develop a low cost phantom capable of producing complex motions useful for both imaging and dosimetric validation studies.
Methods: A dual frequency-oscillating platform capable of simulating 3-dimentional axis motion was developed. It is comprised of two platforms, independently controlled by stepper motors, moving in perpendicular directions. The platforms are made out of acrylic while the wheels are made with delrin. High-frequency platform can move up to 120 fpm on top of a low-frequency platform oscillating up to 25 fpm. Both platforms move on wheels and ride on a curved path to create up/down motion. Both motors are controlled by an Arduino Tian micro-controller board and coded using Arduino software. The platform can be controlled remotely from outside the room utilizing the micro-controllerâ€™s wireless capabilities.
Results: This in-house designed moving platform can support a wide variety of phantoms. A prototype built to the designed specifications showed promise in preliminary studies. Our phantom can mimic simultaneous motion of heart and lungs,. The motion phantom has a limit on maximum range of frequency beyond which the phantom is unable to properly simulate. However, the platform can oscillate a 11 Kg phantom at the stated high-frequency. Major limitation of this platform is it moves the entire phantom, not the internal parts.
Conclusion: The in-house built motion device can be economically built for small-scale operation at standalone clinics. However, due to low cost, the device (< US $1000) requires quality assurance on a regular basis. Commercial phantoms would cost at least 20 times more.
Phantoms, Quality Assurance, Gating
TH- Radiation dose measurement devices: Phantoms for dosimetric measurement