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Session: Therapy General ePoster Viewing [Return to Session]

A Lung Motion Phantom for Free Breathing and DIBH (Deep Inspiration Breathing Hold)

J Kwag1*, (1) North Mississippi Health Services, Tupelo, MS


PO-GePV-T-200 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: To evaluate the functionality of gating QA (Quality Assurance) for free breathing and DIBH (Deep inspiration breath-hold). This is related to a lung motion phantom to track free breathing and DIBH (Deep Inspiratory Breathing Hold) of treating lung cancer patients and left breast patients.

Methods: A phantom is devised from the mechanism of the energy transformation between the rotation and linear motion and combined with the motion of asymmetric rotation to resemble a human lung motion.The free breathing and DIBH pattern were produced by one DC motor with saw-toothed wheels and an application of Scotch York mechanism. A switch bar was used to change the motion patterns. A free breathing pattern was produced from the asymmetric dick connecting a DC motor. A DIBH pattern was created from the application of Scotch Yoke mechanism. The composite breathing pattern of free and DIBH was demonstrated.The deep inspiration was created by rising rotation and the holding pattern was maintained after rising rotation till going down motion. In order to reduce the length of linear motion to the lower direction, a semicircle shape was devised so that the rotation motion was transferred to linear movement connecting the interface device.

Results: The composite breathing patterns of free and DIBH was demonstrated. The radiation on a Varian TrueBeam was controlled by the phantom motion and RPM (Real-Time Positioning Management) gating system. I checked the functionality of RPM gating system in terms of free and DIBH on a daily QA.

Conclusion: From the phantom study, I noticed that the rising and going down motion was not sharper than the real DIBH pattern. To resolve this difficulty, I am working on utilizing a stepper motor to control the different speed of rising, holding, and going down.


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