  Purpose: Anthropomorphic phantoms can be used in radiotherapy to confirm dose
distributions. In this work, a prototype phantom with a deformable chest wall
was created based on real human. Methods: A technique similar to 3-dimensional
printing was utilized, which involved collecting computed tomography (CT)
images of a patient as a reference, contouring the organs, projecting them onto
polystyrene panels, and pouring appropriate material into them. Balloons
attached to a ventilator and an air compressor were used to periodically
generate a breathing cycle. A silicone tumor was also implanted in the lower
lobe of the right balloon to investigate its displacement during respiration.
During silent and deep breathing, qualitative and quantitative tests were
conducted, and the results were compared to research conducted on real humans.
Results: The CT images and the shape of the phantom matches those of the real
patient. However, few organs densities can be optimized. The air pressure in
the ventilator was so weak that it could only create quiet breathing phantom
motion on its own. However, deep breathing phantom motion was obtained manually
by only using the air compressor. As a consequence, reproducibility and
repeatability studies were done only for quiet breathing and results were
acceptable. When compared to the real scenario, the phantom's motion amplitudes
were appropriate, except in the lateral direction and abdomen section, near the
diaphragm, they were negligible. In addition, the tumor displacement was
predominant in the Anterior-Posterior direction rather than the
Superior-Inferior direction as it should be. Conclusions: As a prototype, the
work was successful, nevertheless, several improvements are required, such as
optimization of the shape of the mediastinum and developing a mechanical
diaphragm movement system synced with a high-pressure air pump.
