Abstract：Objective To study the application of self-made motion simulation phantom in dynamic dose verification of
hypofractionated radiation therapy. Methods Motion Simulation Phantom Motion parameter was set as tumor diameter φ 2 cm,
3 cm and 4 cm, Respiratory rate was 0, 12 bpm, 16 bpm and 20 bpm, and Respiratory amplitude λ was 0.25 cm, 0.5 cm, 0.75 cm
and 1 cm. The scanning layer thickness was 3mm with 4D-CT technology. Four-dimensional reconstruction was transferred to TPS.
Clinical target volume, internal target volume and planning target volume (PTV) in the target area were mapped, intensity modulated
radiotherapy plans were designed and transmitted to the accelerator. The Phantom motion parameters were set in accordance with
the planned parameters, and the corresponding plan was executed. The dynamic dose distribution was measured using the film
measurement technique, and static plan validation was performed using a two-dimensional matrix. The dose validation results were
analyzed using gamma analysis method. Results The γ pass rate of the dynamic simulation body model was more than 88% in
the static mode, and was consistent with the results of the two-dimensional matrix, which proves the reliability of the simulation
body model and accelerator system. The dynamic dose validation rate was affected by the ratio of respiratory amplitude, respiratory
frequency, tumor diameter and cross-sectional area under partial exercise conditions, and the γ pass rate was less than 88% and
decreased with the increase of respiratory amplitude. By comparing the dose distribution range with the profile it was found that the
γ passing rate was less than 88% of the test cases. When the range of measured dose value of profile curve covered the planned dose
range, it could indicate whether the PTV was in the prescribed dose irradiation range under the exercise state, indicating that the γ
pass rate combined with profile curve analysis could indicate whether the thoracic and abdominal plan design met the requirements.
